EARTH SCIENCES CENTRE GÖTEBORG UNIVERSITY B157 1998

THE SPATIAL RELATIONSHIP BETWEEN PHYSICAL FEATURES AND THE UTILIZATION OF LAND -A Land Capability Classification within the Regencies of Sleman & Gunung Kidul, Special Province ,

Marie-Charlotte Enryd

Department of Physical Geography GÖTEBORG 1998

2 3 GÖTEBORGS UNIVERSITET Institutionen för geovetenskaper Naturgeografi Geovetarcentrum

THE SPATIAL RELATIONSHIP BETWEEN PHYSICAL FEATURES AND THE UTILIZATION OF LAND -A Land Capability Classification within the Regencies of Sleman & Gunung Kidul, Special Province Yogyakarta, Indonesia

Marie-Charlotte Enryd

ISSN 1400-3821 B157 D-geografi Göteborg 1998

Postadress Besöksadress Telefo Telfax Earth Sciences Centre Geovetarcentrum Geovetarcentrum 031-773 19 51 031-773 19 86 Göteborg University Box 46 Guldhedsgatan 5A Box 460 413 81 Göteborg S-413 81 Göteborg SWEDEN 4 5 1. SUMMARY The physical features within the study area, embracing parts of the regencies Sleman and Gunung Kidul, Special Province Yogyakarta, are distinct. The southern slope of the Merapi volcano in the Northeastern part of the Sleman consists of a more uniform composition of material with volcanic origin together with a thick soil, which makes the land suitable for cultivation. The opposite situation occurs in the karstic areas of Gunung Kidul. Marl and limestone dominate the more heterogeneous lithologic compositions and the soil layer are usually very thin, with exception for some parts receiving deposits from upslope. The topography is hilly and sometimes very steep. Soil profiles located along the volcanic slope contain pyroclastics from the last eruption in November 1994, and the layers between the horizons were diffuse and therefore difficult to separate. Profiles taken further down the slope have according to the normal processes in a catena coarser texture and therefore also higher drainage and lower shear strength. The very thin and clayey soil profiles within the limestone areas of Gunung Kidul have moderate to low infiltration rates in most of the cases and accumulation of calcium carbonate is also common. Even though the soil profiles along the Merapi slope indicates very advantageous conditions, further laboratory analysis of the soil characteristics showed that the amount of exchangeable cations along the Merapi is low, especially potassium. This may be a result of leaching losses that usually occurs within coarse-textured soils along slopes and can in a long- term result in degradation of land. Soils in Gunung Kidul have more exchangeable cations because of its calcic parent material and clayey texture, although extremely severe sodic conditions were also noted for most of the sites. Sodium soils have deleterious effects on soil structure, and therefore also on the infiltration. This together with the accumulation of calcium carbonate is therefore an important factor that together with the hilly topography increases the erodibility of land. Soil erosion within the regency of Sleman is hardly existing except in the steep cone area of the volcano were slides occur. Estimations with Universal Soil Loss Equation (USLE) although point out some of the drylands along the upper slope to be highly subjected for erosion. This may be the case if degradation of the land will continue, but present land utilization so far seem to have a good effect promoting soil loss to occur in larger quantities. The soils in the regency of Gunung Kidul are in contrast very exposed for soil erosion. Erosion hazard mapping carried out during fieldwork indicates severe to extremely severe hazards in a dominant part of Gunung Kidul, especially the coastal region together with sites located along river Oyo positioned in the centre of the regency. Vegetation is an important factor to offset the effects of erosion, and several revegetation programmes therefore occur within the study area. Since the whole study area is under intensive cultivation, the human impact has the most significant influence on soil erosion including land utilization as well as the management of land. The very different physical conditions existing within the study area is in response to that deciding the distribution of the economical profits for the farmers. Farmers in Gunung Kidul for that reason have a very low income, and poor villages have been priority for community forests. However, the very high population pressure and economical situation has in big extension already resulted in an exceeded land capability in Gunung Kidul with the results that the productivity together with the thickness of the soil layer according to the farmers is decreasing for every year.

1 2. INTISARI Daerah penelitian meliputi kabupaten Sleman dan Kabupaten Gunung Kidul, DIY mempunyai karakteristik phisik yang berbeda. Lereng sebelah utara gunung Merapi pada Kabupaten Sleman sebelah Norheastern mengandung banyak material Volcanic origin dan lapisan tanah yang tebal. Sehingga lahan tersebut cocok untuk pertanian. Situasi berlawanan di Gunung Kidul yang merupakan kartic. Marl dan Limestone medominasi komposisi litholosi lebih heterogen dan lapisan tanah biasanya sangat tipis, dan beberapa tempat menerima endapan dari atas lereng (upslope). Topograpi berbukit dan kadang sangat curam. Profil tanah di lereng Merapi tampak sangat menguntungkan, berdasarkan analisa karakteristik tanah memperlihatkan bahwa jumlah pertukaran kation di daerah Merapi adalah rendah terutama potasium. Keadaan ini mungkin hasil dari leaching loss yang biasa disebabkan pada tanah bertekstur coarse di daerah lereng. Dan pada jangka panjang bisa menyebabkan degradasi pada tanah. Tanah di Gunung Kidul mempunyai banyak pertukaran kation sebab daerah tersebut mempunyai material calcic dan tektur clayey meskipun beberapa daerah berkondisi sodic sangat ekstrim.Tanah Sodium mempunyai efek merusak pada struktur tanah dan peresapan . Sodium bersama dengan akumulasi kalsium karbonat faktor yang penting bersama dengan topografi yang berbukit meningkatkan erodibility lahan. Erosi tanah di Kabupaten Sleman rendah kecuali pada daerah cone vulkanik terdapat longsoran tanah. Perhitungan erosi dengan USLE (Universal Soil Loss Equation) memperlihatkan dryland sepanjang lereng bagian atas potensial terjadi erosi. Hal ini akan menjadi masalah apabila degradasi tanah terus berlangsung, tetapi penggunaan lahan di daerah tersebut kelihatan mempunyai pengaruh baik untuk menanggulangi erosi tanah dalam jumlah yang besar. Tanah di Kabupaten Gunung Kidul sangat kontras memperlihatkan erosi tanah. Pemetaan bahaya erosi dilaksanakan selama fieldwork menunjukkan tingkat parah ke tingkat ektrim sangat parah pada sebagian besar daerah Gunung Kidul, khususnya pada daerah pantai bersama lokasi sepanjang sungai Oyo yang terletak di pusat kabupaten Gunung Kidul. Vegetasi merupakan faktor penting untuk penanggulangan erosi dan beberapa program penghijauan dilaksanakan di daerah penelitian. Kondisi daerah penelitian adalah lahan pengolahan intensif maka faktor manusia sangat berpengaruh terhadap erosi termasuk pemanfaatan lahan dan juga manajemen lahan. Kondisi phisik yang sangat berbeda terdapat di daerah penelitian menghasilkan keputusan distribusi keuntungan secara ekonomi bagi petani. Petani di Gunung Kidul mempunyai pendapatan rendah dan miskin telah menjadi prioritas community forests. Bagaimanapun tekanan penduduk dan situasi ekonomi menyebabkan melebihi kemampuan lahan di Gunung Kidul dimana produktifitas dan lapisan ketebalan tanah berkurang setiap tahunnya. Profil tanah yang terletak di sepanjang lereng vulkanik mengandung pyroclastics dari letusan merapi pada bulan November 1994, dan lapisan antar horison sangat dalam sehingga sulit dibedakan. Profile sepanjang bawah lereng menunjukkan proses normal mempunyai tekstur coarser catena dan juga karena dranasi yang tinggi dan kekuatan shear yang rendah. Profile tanah sangat tipis dan clayey di daerah limstone Gunung Kidul mempunyai peresaman (infiltrasi) moderat sampai rendah dan akumulasi kalsium karbonat sangat umum.

2 3. ACKNOWLEDGEMENT During the preparation, practical performance and the final compile of this thesis a great deal of people has been involved. They have all in some way with great concern contributed to innumerable solutions of practical, theoretical and emotional problems that appeared in the sometimes most unexpected moments. At home, Göteborg University, Department of Earth Sciences/Physical Geography, I would like to express my very big appreciation and respect to my supervisor Dr. Margit Werner, lecturer in Geography. Her enthusiasm and concern has by far extended outside the usual supervision procedures. During my intensive 4-month period in Indonesia I was stationed at the Faculty of Forestry, Gadjah Mada University in Yogyakarta, Java. Many people have during that time been involved in my research in a sometimes overwhelming way. I would therefore now like to pay them some attention. Firstly I would like to thank the Dean at the faculty of Forestry, Dr. Ir. Sambas Sabarnurdin. MSc., for giving me the very pleasant opportunity to study at the faculty. My practical training there was under the supervision of Dr. Ir. Agus Setyarso MSc. This admirable and unselfish man simply did everything to facilitate my visit down there and I am very grateful for that. I would further like to thank all other people that has contributed to this thesis. In Sweden; At Department of Human Geography, Umeå University, Umeå: · Margit Söderberg & Fred Hedkvist for their contribution to the received grant by Sida. At Department of Earth Sciences/Physical Geography, Göteborg University, Göteborg: · Dr. Mats Olvmo, Vice Chancellor and lecturer in Physical Geography for the lending of Field Equipment In Indonesia; At the Head Office for Foreign Affairs, Gadjah Mada University, Yogyakarta · Dr. Hurdoyo, head responsible for foreign matters, for the approval and extension of my practical training at the university · Mrs Suhartini, assistant of foreign academic matters, for the facilitating help concerning my practical training At Faculty of Forestry, Gadjah Mada University, Yogyakarta · Dra. Ninik Supriyantini, head of academic affairs, as well as other assistants at the Dean's office for helping me with all administrative matters. · Dr. Ir. Fanani & assistant Sarifudin for matters concerning GIS. · Agus Cahyono, assistant in Soil Science for theoretical material · Djoko Supriadi S.Hut for assistants of several matters within the research · Ari Susanti & Wijonarko Suhari (my left and right hand) for 24-hours assistance, including practical, theoretical and emotional matters. · The very friendly students and other people concerned, at the Biometrics Laboratory of Forest Management, for support within all kinds of matter. At Faculty of Geography, Gadjah Mada University, Yogyakarta · The Dean Dr. Ir. Sutikno MSc Geography for the approval of GIS application at the faculty's GIS laboratory · Dr. Ir. Hartono, head responsible for the GIS laboratory who in the first place suggested me to stay at the faculty for the GIS application · Ir. Heru, lecturer in geography at the faculty who with great concern guided me through the sometimes confusing moments of the GIS application · Junun Sartohadi M.Sc. Geography for lending me the Soil Profile Description sheet · The very helpful students within the GIS laboratory for practical help At Department of Soil Science, Faculty of Agriculture, Gadjah Mada University, Yogyakarta · Dr. Ir. Dja´far Shidiq for the generous lending of field equipment together with other data concerning the research · All people concerned at the soil laboratory, for help with the analysis of my samples To all other People Concerned · Jozsef Micski, Deputy Director at Forest Liaison Bureau, who in the first helped me to established contacts in Indonesia · All people concerned at the Office for Province Development Planning (BAPPEDA), Yogyakarta for help with permissions concerning the performance of the research · All people concerned at the Offices for the Gunung Kidul respective Development Planning (BAPPEDA), Yogyakarta for help with permissions concerning the performance of the research · All people concerned at the Offices for social and politics in Yogyakarta, Sleman respective Gunung Kidul, Yogyakarta for the help to get permissions for samplings and Interviews within the Study Area · All people concerned at the Province office (Kantor Wilayah), Department of Forestry in Yogyakarta for giving the approval to study satellite images, maps and other data · Ir. Sukasno, Ir. Suparto, Ir. Suharsono & Ir. Sutamto and all other people at the Rehabilitation and Land Conservation Bureau (RLKT), Department of Forestry, Yogyakarta for their kindly cooperativeness concerning maps, literature, statistics and interviews. · All people concerned at the Forestry office (Dinas Kehutanan), Department of Forestry, Yogyakarta for help with the collection of maps and statistics · All people concerned at the Province office (Kantor Wilayah), Department of Agriculture in Yogyakarta for help with the collection of maps and statistics · Reidar Persson, Project Leader at CIFOR (Centre for International Forestry Research), for recommending of literature

3 I would also like to pay my respect to the very courteous farmers within the study area, and all other people not earlier mentioned that all in some way have been involved during the process.

4

LIST OF CONTENTS

1. SUMMARY 2. INTISARI 3. ACKNOWLEDGEMENT LIST OF FIGURES AND TABLES p.3 I. INTRODUCTION p.4 1. Statement of the problems p.6 1.1 Historical Influences p.6 1.2 Contemporary Situation p.6 2. Research Objectives p.8 II. GEOGRAPHICAL OVERVIEW p. 9 1. Indonesia p.9 2. Java p.9 3. Daerah Istimewa Yogyakarta (Special Province) p.10 III. THEORETICAL FRAMEWORK p.12 1. Land Degradation p.12 2. Land Evaluation System p.12 2.1. Land Capability Classification p.13

2.2. Erosion Hazard Assessment p.13 3. Factors Influencing Erosion p.14 3.1. Relationships between Land Use and Erosion p.15 3.2. Land Management and Soil Conservation p.15 IV. RESEARCH PROCEDURES p.17 1. Delineation of Scope of Work p.17 2. Methods p.17 2.1. Data Collection Phase p.17 2.2. Fieldwork Phase p.17 2.3. Compile Phase p.18 2.4. The Application of GIS p.20 V. RESULTS p.23 1. The Study Area p.23 1.1 Physical Features p.24 1.2. Population Status p.29 1.3. Summary of Results p.31

1 2. The Area of Focus p.33 2.1. Sampling Sites p.34 Soil Profile Description p.40 2.2. Soil Characteristics p.42 3. Land System Analysis p.44 3.1. Erosion Hazard Assessment p.44 Soil Loss p.44 3.2. Land Capability Classification p.47 4. Local Knowledge in Land Management p. 47 VI. DISCUSSION p.50 VII. CONCLUDING REMARKS p.54 VIII. REFERENCES p.56 IX. APPENDIX p.59 1. Geographical Description p.59 1. Indonesia p.59 2. Java p.60 3. Daerah Istimewa Yogyakarta (Special Province) p.61 3.1. Physiographic Conditions p.61 Geomorphology p. 61 Topography p.61 Climate p.62 Vegetation & Land Use p.62 Soils p.64 Hydrology p.64 3.2. Population Status p.65 Demography p.65 Socio-Economic & Cultural Parameters p.66 2. TP-formula p.67 3. Universal Soil Loss Equation (USLE) - Calculations p.67 4. Questionnaires p.68 5. Common Crops and Vegetation Types within the Study Area p.70 6. Soil Survey p.71

2 3 List of Figures & Tables Fig.1 The Plain Field of Daerah Istimewa Yogyakarta (Special Province) with in the Background. Fig.2. Republic of Indonesia, and Java's geographical location in Indonesia. Fig.3. Erosion risks across , and D.I. Yogyakarta. 1990. Fig.4. Wet Paddy Rice Cultivation on the Coastal Plain, Sempor, Central Java. Fig.5. Administrative Map of Daerah Istimewa Yogyakarta (Special Province) Fig.6. Land Evaluation System Fig.7. Dryland with Multiple Cropping of a great various of species in the hilly areas, terraced wet paddy rice fields in lower altitudes, Gunung Kidul Fig.8. Flowchart over the Operational Steps within the Research. Fig.9. Flowchart over the Operational Steps for Creation of the Land Capability Map Fig.10. Flowchart over the Operational Steps for Creation of the Recommended Land Use Map Fig.11a,b,c.Geographical Overview of the Study Area. a) Special Province Yogyakarta with Limitations for the Study Area b) The Study Area c) The Area of Focus Fig.12. Geomorphology Map of the study area Fig.13. Slope Map of the Study Area Fig.14. Rainfall Map of the Study Area. Fig.15. Land Use within the Study Area Fig.16. Soil Map of the Study Area Fig.17. Orange coloured Soil Deposits dominates the Landscape in Patuk, Gunung Kidul. Fig.18. Groundwater Map Fig.19. The distribution of Land Utilisation Types in the Sleman Regency (1996). Fig.20. The distribution of Land Utilisation Types in the (1996). Fig.21. Map of Sampling Sites Fig.22. Land Mapping Units within the Study Area. Fig.23. Landslides along the Volcanic Cone. Fig.24. Wet Paddy Rice Field in Turi, Sleman (Not a Sampling Site) Fig.25. Mud Cracking in Patuk Fig.26. Eroded Kayu Putih Cultivation Fig.27. Calcic ground in Baron Fig.28. Soil Profiles within the Study Area. Fig.29. Erosion Hazard Map Fig.30. Soil Loss Map of the Study Area. Fig.31. Land Capability Map Fig.32. Map of Recommended Land Use Fig.33. Monthly averages precipitation for each of the regencies with average monthly temperature and relative monthly humidity given for the whole area (D.I.Yogyakarta) Fig.34. River Oyo running through in Playen, Gunung Kidul. ------Tab.1. Physical Features within the study Area Tab.2. Population Status within the Study Area Tab.3. ESP- Value for the Different Sites. Tab.4. Description of the Physical Features within the Sampling Sites. Tab.5. Soil Characteristics. Tab.6. Original and Present Forest Cover in Java. Tab.7a,b. a) Distribution of Land Area Based on Altitude in Special Province Yogyakarta. b) Distribution of Land Area Based on Slope Degree for Each Regency/Municipality. Tab.8. Number of rainy days (1996), in each regency. Tab.9. The spatial distribution and quantity of forest for each regency Tab.10. Area of wetland and dryland by utilisation in D.I.Yogyakarta (1996), and its distribution for each regency/municipality in percent. Tab.11. Population distribution, density and growth for each regency/municipality in D.I.Yogyakarta, 1996, and its total land area and administrative sub-divisions. Tab.12. TP-Calculations based on Agroforestry within each of the Regencies. Tab.13. Soil Loss Estimations within the Study Area. Tab.14. Plant Species within the Study Area, and their Main Use. 4 I. INTRODUCTION In comparison to many other developing countries, Indonesia appears to be relatively rich in land, population and natural resources. With an estimated population of 201.5 million people (Microsoft Corporation, 1998), this archipelago ranks fourth among the world's most populous countries. Indonesia is also the world's largest island nation, and although most of the islands are sparsely populated the distribution of people is exceedingly uneven. Census data from 1990 show that approximately 60% of the Indonesian people live on the island of Java (Fig.2), an area amounting to a mere 7 % of the total land area of the country (Marcoux, 1996). This situation is causing several environmental problems and therefore also social and economical problems, and vice versa, within the country. One of the most urgent problems that occurs is concerning the high population pressure in relation to the capability of land, including land degradation, such as soil erosion and decreasing productivity. My personal interest in Indonesia, and to get working experiences with Land Evaluation Systems, therefore led to this M.Sc. thesis in Geography, combined with a Minor Field Study (MFS). The study was financed through a grant from Sida (Swedish International Development Agency) via the Department of Human Geography at Umeå University. This thesis is concerning a so called specific purposed land evaluation that is a complex subject field suitable for people with a multidisciplinary background of which geography is included to a great extent. These specific purpose processes in this case comprise interpretation and comparison for two areas with different physiographic features. Since studies within Land Evaluation Systems include several problem areas, I decided to concentrate on physiographic features of the land in relation to human impact. The overarching aim within this study is therefore to indicate how these physiographic features affects the people and people's respond to the characteristics of the land system. For that reason I chose to focus on an area in the most overpopulated and fertile part of Java, where the historical influences has been of great importance for the situation occurring today (Fig.1).

Fig.1 The Plain Field of Daerah Istimewa Yogyakarta (Special Province) with Mount Merapi in the Background (Photo M. Enryd 1998).

5 Fig.2. Republic of Indonesia, and Java's geographical location in Indonesia.

6 1. Statement of the problems Problems occurring today, concerning land degradation on Java are mainly considered to be of historical influences. A short historical resume, taken from Witten et al. pp.328-331, will therefore first be presented below.

1.1. Historical Influences People have lived on Java and Bali for about one million years, and human impact on the forest and the flora began as soon as cutting tools and fire were available. The first major loss of natural forest probably occurred after teak was introduced (200-400 AD). By the time the Hindu-Buddhist temples of Central Java were being built, appreciable areas of forest had probably been cleared. Irrigated rice culture was introduced over 1,000 years ago, probably confined to the lower slopes. Major change began in 1830 during the Dutch control, when farmers were forced to grow export crops among the food crops, usually on forested grounds. The people had to grow cash crops at the expense of food to satisfy the desires from Europe. The human population grew rapidly and the land became crowded, forcing farmers to use more intensive forms of agriculture. In 1870, more than 300.000 ha of Java were used for coffee plantations, especially in the east and central regions. The northern half of the island, with malaria-infested alluvial coastal plains, remained uncultivated until between 1850 and World War I, when these land was brought under cultivation. Between 1898 and 1937, some 22.000 km2 of natural forest were lost, because of the building of the railway network. During World War II, there was widespread and uncontrolled deforestation, and during the difficult years of the 1940s and 1950s. In the 1980s all Javanese and European farmers were required to protect the soil on sloping fields with the result that large areas were terraced. The area under cultivation although increased so rapidly, and on to more and more marginal land by poorer and poorer farmers, that it was impossible to control land management.

1.2 Contemporary Situation Agriculture is the most important sector in Indonesia and is characterised by family based, small farm holdings. The average farm size in Java is about 0.20 ha while on the outer islands it is approximately 0.80 ha (Martaamidjaja 1996). Java has fertile volcanic soils but even so there are limits to its human carrying capacity and a voluntary resettlement scheme, now called the Transmigration Program, has been operating ever since 1905 as an attempt to reduce the tremendous pressure (Marcoux, 1996). As a consequence of population pressure and intense development activities, the industrial and housing sector's need for land is rapidly increasing. More and more, agricultural and forest areas are being encroached to meet this need. In 1991, the remaining forest area in Java comprised only 4.6 percent of the total land (Martaamidjaja 1996). Central Java is Indonesia's least-forested province, with an average population density of 833/km2 (Microsoft Corporation 1998). About 50% of the rural Javanese farmers, whose income is solely from agriculture, do not have enough land for farming (Muhamud 1996, p. 6). Such a condition combined with the increasing demand for food and other products from the land has forced the farmers to use land, which is not suitable for agriculture. When demand for land is not matching the land capability this will result in an increasing pressure, finally forcing the land to its carrying capacity.

7 This has resulted in degradation of land through the process of soil erosion, especially occurring in steep hilly areas. The degradation of land is strongly connected with the high population pressure of the island, and its physical environment. Java experiences some of the highest rates of erosion in the world and the soil loss is enormous. It is beneficial to consider that 15% or 1.9 million ha of Java is regarded as 'critical' or subject to serious erosion (Fig.3), and that this area are inhabited by some 12 million people (Whitten et al. 1996, pp. 45-46).

Fig.3. Erosion risks across Central Java, and D.I. Yogyakarta. 1990. (Simplified after Whitten et al).

8 2. Research Objectives Scope of work The overarching aim of this study is to indicate how the physiographic features of land affects the people and people's respond to the characteristics of the land system, and can be split into several significant objectives as follows:

One purpose is to estimate and classify the land capability, with special focus on erosion hazards, for two areas with different physiographic conditions. This is carried out to assess the physical limitations of the land. In order to get this assessments transformed to a statement or indication of how fast the rate of soil loss is the Universal Soil Loss Equation (USLE), based on field data, will be used as a further purpose. The use of USLE also requires more knowledge about crop management and erosion control practices in the area of concern. Therefore, another purpose was to study the effect of human impact on the land, especially with focus on existing land use and land management, and its relationship and influence on physical and chemical soil properties in terms of degradation, erosion and fertility. Since the requirements and quality of land not always match it is also of great importance to understand the socio-economic and cultural situation in the area. For that reason an important purpose, as a step towards more knowledge, is an attempt to understand how the physical features of the land affects the people, and people's respond to the characteristic of the physical land system.

Objectives I. Elaborate land utilisation type. II. Classify terrain stability with focus on erosion risk and slope stability. III. Indicate land capability with respect to erosion hazards and soil characteristics. IV. Estimate land capability with GIS by the use of erosion mapping and other data. V. Identify the influence of socio-economic & cultural factors as well as land management and conservation practices on land degradation.

As a further important purpose in this research a recommendation map concerning land use within the area was made. The aim with this map was to indicate how balanced conditions, or matching between the physical features and utilization of land within the study area can be achieved. A combine of my own field data together with some local knowledge about the study area was used. That achieved a creation of a more realistic situation.

9 II. GEOGRAPHICAL OVERVIEW This thesis concerns a study area positioned in the regencies of Sleman respective Gunung Kidul within Daerah Istimewa Yogyakarta (special province), which is located in the central parts of Java Island, Indonesia. A short overview of Indonesia, Java and Daerah Istimewa Yogyakarta will firstly be introduced for a better understanding of the actually study area in relation to the local, regional and national environment For further details see app.1 pp. 59-66).

Indonesia, an archipelago with a population density of 103 people/km2, is stretching from 94°45' to 141°05' E, and 6°08' N to 11°15' S, crossed by the line of Equator (Fig.2). It is the world’s largest archipelago with a total of about 13 600 islands occupying a total area of about 1 .919.400 km2. The South China Sea borders in the west and the south by the Indian Ocean and in the west by the Pacific Ocean and in the north the country A chain of volcanic mountains, many of them still active, is rising to heights of more than 3568 m extends from west to east through the southern islands from Sumatra to Timor. Each of the northern islands has a mountain mass, with plains around the coasts. The most extensive lowland areas are on Sumatra, Java, Kalimantan, and Irian Jaya (Diercke Weltatlas 1992). The climate is tropical, with a wet season from November to March and a dry season from June to October. Humidity and temperature is relative high and the precipitation varies from low in the lowlands to very high in the mountain areas (Microsoft Corporation 1998). About two-thirds of Indonesia is covered with forests and woodland, mostly concentrated on Kalimantan, Sumatra, and eastern Indonesia. About 12% of Indonesia is under cultivation and about 55% of the country's approximately 70.4 million workers are engaged in agriculture, either as owners of small farms or as labourers on estates (BPS, Kantor Statistik Jawa Tengah 1996). Java is located between 114°04' E, and 104°48' S to 7°12' S longitude, with a size of about 130.000 km2, split into different regions (Fig.2), is the economic, social, political and cultural hub of Indonesia, with one of the densest concentrations of population anywhere in the world. In 1995, Java had about 114 million inhabitants living at an average density of 862 people/km2, ranging from nearly 40.000 in some parts of Jakarta, the capital of Indonesia, to virtually zero in some of the remaining wild areas (Microsoft Corporation, 1998). The island is the most volcanically active island in the world (Microsoft Corporation 1998). Mountains ranging between 3.000 and 3.800 m.a.s.l can be found (Indonesia-a country study, 1992). A low coastal plane (Fig.4), with an average height of 250 m (FAO-Unesco 1974, p.47), adjoins the mountains on the north, and the southern part of the island is a serie of limestone ridges (Microsoft Corporation, 1998), forming a landscape of tropical karst. Winds are moderate and generally predictable, with monsoons usually blowing in from the south and east in June through September and from the Northwest in December through March (Indonesia-a country study 1992). Dry season in Java normally last from March to August, wet season from September through March (travel-Indonesia 1996). About 90 % of Java and Bali receive at least 1,500 mm in annual precipitation, and the temperature usually ranges between 20°C and 30°C, the humidity between 60% to 90%. (Indonesia-a case study 1992).

The present remaining forested area on Java is less compared with other islands, only covering less than 10% of the land area (Ross 1984, p.10). Dominating utilization types includes wetlands, tree crops, and upland farming which also is specific for this island (World Bank, 1994).

10 Fig.4. Wet Paddy Rice Cultivation on the Coastal Plain, Sempor, Central Java (Photo M. Enryd 1998).

Daerah Istimewa Yogyakarta (special Province, located between 7° 33' until 8° 12' E, and 110 °00' until 110° 50', on the central part of Java is divided into four Kabupaten (Regencies) and one Kota Madya (Municipality), with a total land area of 3.185.80 km2 (0.17% of the total land area of Indonesia), split into several Kecamatan (Sub-districts) and Desa (Villages). Yogyakarta is the municipally of the province, surrounded by the regency of Sleman in the north, Kulon Progo in the west, Bantul in the Southwest, and Gunung Kidul in Southeast (Fig.5). Each of the regencies has a very specific geomorphic location, but the structure of the Yogyakarta area and its surroundings is strongly influenced by plate and tectonic movements, and volcanic deposits from the still active strato volcano. (Sutikno 1996, p.3). The topography within the special district varies from flat to mountainous with about 65% of the total area having an elevation between 100-500 m.a.s.l. Steep areas (>40%) is mostly found in the cone area, west Kulon Progo, and the coastal south. The central of the special province consists of a big plain area. Remaining areas are varying a lot on a local scale between 2-15% in steepness. Special Province Yogyakarta is located in a humid tropical area with average humidity and temperature as described for Java in general. Amount of precipitation is depending on altitude, showing significant higher amounts in the volcanic area. Dryland cultivation's is the dominating land utilization type within all regencies, mostly consisting of dryfields. Forests are more concentrated to the Bantul and Gunung Kidul regency. Irrigated wet paddy rice embraces most of the wetland areas and the majority of the rice fields are concentrated along the volcanic slope in the Sleman regency.

11 Fig.5. Administrative Map of Daerah Istimewa Yogyakarta (Special Province). (Source: Peta Fisiografi. Propinsi D.I.Y., scale1: 250.000, Mitojat dkk (1987)).

Volcanic Regosols (inceptisols & entisols) dominates the slopes of Mt. Merapi, litosols (entisols) is more common in the plain areas, and a great variation of grumosols (vertisols), Litosols (entisols) and Rensina (entisols) is found in remaining areas. There are several rivers within the special district, as well as underwater rivers. Big parts of the special district are non-aquifer or comprise a shallow depth of the groundwater (<7m). This with exemption of the Merapi slope and plateau, having considerable deeper levels. D.I. Yogyakarta, located on the fertile foot plain of Mt. Merapi, is considered as the cradle of the Javanese culture, which makes it one of the most popular tourist destinations in the Indonesian archipelago. The municipality Yogyakarta also has a long established reputation as the educational centre of Indonesia with several privates and government owned universities. Therefore, D.I. Yogyakarta is one of the most densely populated areas in Indonesia, with a density of 999.87 persons per km2 (Tab.6). Most of the people within the Special Province are in some way depending on agriculture for their living. The economical situation varies a lot on a relative local scale, of which the volcanic influenced areas together with the city have higher income. The traditional thinking among farmers within the regencies is strong, and the use of plants for a wide range of medicinal cures is common.

12 III. THEORETICAL FRAMEWORK

1. Soil Degradation Soil degradation is a common problem all over the world and in recent decades the global rate of soil degradation has increased dramatically, and is likely to increase further as we approach the twenty-first century. The term Soil degradation refers to the decline in soil productivity through adverse changes in for example nutrient status, organic matter, structural stability and concentration of toxic chemical. It incorporates a number of environmental problems including erosion, compaction, water excess and deficit, acidification, salinisation and sodifiction, toxic accumulations of agricultural chemical etc. These factors have led to serious decline in soil quality and productivity (Ellis & Mellor 1996, pp. 238-239). Soil degradation in Indonesia is one of the nations most serious degradation problems, and varies a lot between the many islands. Kalimantan, with large quantity of forest suffers from low productive soils due to deforestation and other qualities of the soil characteristics. Areas with more fertile soils such as the areas within the volcanic chain, stretching from Sumatra in north down to The Smaller Sunda Islands, have high amount of soil loss because of the more steep topography together with a lack of dense vegetation cover. Specific for these areas is also the periodic burial of soil profiles together with the burning of existing vegetation caused by volcanic eruptions (Oral Setyarso 1998). This thesis has its focus on soil erosion, which, according to Morgan (1995) is a hazard traditionally associated with agriculture in tropical and semi-arid areas. Defined by Trudgill (1983) it includes the removal and transport of material from its original site by an agency such as water, wind or ice. Various types of erosion can be found and specific for a tropical environment is, according to Morgan (1995) rainsplash erosion; overland flow (sheet), subsurface flow, rill erosion and gully erosion. Soil erosion on Java is mainly a result of inappropriate land management, and much erosion occurs from fields, bare roads, and roadside paths, open villages areas, landslides, incised riverbanks (Witten et al. 1996, p. 142).

2. The land Evaluation System Land systems analysis is used to compile information on the physical environment. The process of identifying a certain land system is by comparing the present land use, or Land Utilization Type with the natural features of the land and its significant influence on the potential land use. A Land Utilization type, including its technical specifications within a given settling of physical, environmental, and social parameters will have certain requirements on the land. This as well as certain limitations that will adversely affect the potential of land for a specific use (Swedforest International AB & PT. Wahanabhakti Persadajaya, 1995, p. 16). To be able to compare land and land use, or evaluate land for specific use, the land has to be classified into areal units or land systems, which are made up of smaller units, or land mapping units (LMU) (Morgan 1995, p.54). Land mapping units refers to a land unit of any size that can be delineated as long as the features it reflects are uniform, and particularly land form, soil and vegetation cover is of great importance (Swedforest International AB & PT. Wahanabhakti Persadajaya 1995, p. 29). In order to evaluate the sustainability of a specific land unit for a certain land utilization type, the land units will be described in quality terms, which in turn can be compared with the requirements of the land utilization type. Land Quality must then be broken down into Land Characteristics e.g., properties of the land that can be measured or estimated and thus make it possible to compare the specific land use requirements. In the comparison, or matching knowledge on land use is combined with the information of the land into Land Use Systems.

13 These are defined as a specific land Use type, including its inputs and outputs, applied on a specific Land Unit (Fig.6) (Swedforest International AB & PT. Wahanabhakti Persadajaya 1995, p.16).

The Land Evaluation System

LAND USE Physical Features Influencing Factors Geomorphology Social Topography Cultural Climate Economical Technical Vegetation/Crops LMU Utilization Type Soils Hydrology

Land Characteristics Requirements & Land Qualities

Matching

Erosion Manageability

Land Capability

Fig.6. Land Evaluation System (Source: Setyarso 1998).

2.1 Land Capability Classification This method is used for assessing the extent to which limitations such as erosion risk, soil depth; wetness and climate hinder the agricultural use that can be made of the land. The aim of developing land capability classification is to use the land in accordance with its capability so that optimal productivity is attained without destruction taking place on the land (Muhamud 1996 p.31). The objectives are to regionalize an area of land into units with similar kinds and degree of limitation (Morgan 1995 p.47). The capability unit is the basic unit. It consists of a group of soil types of sufficiently similar conditions of profile form, slope, soil structure, soil texture, drainage and other physical properties, such as degree of erosion as to make them suitable for similar crops and warrant the use of similar conservation measures (Muhamud 1996, p.31). ''The capability units are then combined into sub-classes according to the nature of the limiting factor and these, in turn, are grouped into classes based on the degree of limitation'' (Morgan 1995, p.47).

2.3 Erosion Hazard Assessments Many of the factors examined in land systems analysis are relevant to the soil erosion system, in terms of erosion risk evaluation. The assessment of erosion hazard is a specialised form of land resource evaluation, the objective of which is to identify those areas of land where the maximum sustained productivity for a given land use is threatened by excessive soil loss. The assessment aims at dividing a land area into regions, or land mapping units, similar in their degree and kind of erosion hazard (Morgan 1996, p.40). The degree of soil erosion hazard will indicate on the intensity of soil degradation in a specific area, and can then be used to determine priority for soil conservation practices. In order to get a better understanding of the dynamics of erosion further

14 mapping of both the erosion features and the factors influencing them is necessary. Another important issue is to find relationships between the two.

3. Factors Influencing Erosion The factors controlling soil erosion are according to Morgan (1995) the erosivity of the eroding agent, the erodibility of the soil, the slope of the land and the nature of the plant cover. Other factors taken under consideration are land management and utilisation of land. "Land utilisation is perhaps the most significant factor influencing soil erosion, for two main reasons. First, many land use practices leave the soil devoid of a protective vegetation cover, or with only a partial cover, for significant periods of time and second, they involve mechanical disturbance of the soil" (Ellis & Mellor 1996, p.243). Thus, it is likely that the balance of the different degradation factors in different areas will vary (Yanda 1995, p.35). Erosivity is a measure of the potential of the eroding agent to erode and is commonly expressed in terms of kinetic energy (Ellis & Mellor 1996 p. 242). High erosivity of tropical rains is attributed to its intensity, big drop size, and to wind velocity that increases the energy load (Boodt & Gabriels 1980, p.143). The rain also contributes to soil loss through surface runoff. Erodibility of the soil is a measure of its resistance to detachment and transport, and depends on many factors, which fall into two groups; those which are the actual physical features of the soil; and those which are a result of human use of the soil (Selby 1993, p.226). Erodibility varies with a number of soil characteristics, particularly texture, organic content, structure and permeability (Ellis & Mellor 1996, p.242), and also on its shear strength, infiltration and chemical content (Morgan 1995, p.29). Although a soil's resistance to erosion depends in part on topographic position, slope steepness and the amount of disturbance, for example during tillage (Morgan 1995, p.29). The properties of soil horizons determine the rate of infiltration and the amount of water that penetrates further into the soil and eventually down to the ground water. Also, different soil horizons have different erodibility (Yanda 1995). In terms of both water and wind erosion, the most erodible soils tend to be characterised by low clay and organic contents, and poor structural stability (Ellis & Mellor 1996, p.242). The resistance of soil to detachment by raindrop impacts depends upon its shear strength, that is its cohesion and angle of friction (Selby 1993, p.226). The topographic factor is evident in the steepness and length of slopes. Raindrop splash will move material further down steep slopes than down gentle ones, there is likely to be more runoff, and runoff velocities will be faster. On steeper slopes the process can be intense enough to form gullies. Because of these combinations of factors the amount of erosion is not just proportional to the steepness of the slope, but rises rapidly with increasing angle (Selby 1993, p.224). Long slopes are more affected and particularly those which drain a large subcatchment area (Yanda 1995, p.66). The vegetation factor offsets the effects on erosion of the other factors-climate, topography and soil characteristics. The major effects of vegetation fall into different categories: (A) The interception of rainfall by preventing the drops from reaching the soil and harm the structure. It also allows water to be evaporated directly from leaves and stems, (B) Decreasing of runoff velocity and hence the cutting action of water and its capacity to entrain sediment, (C) Increasing soil strength, granulation, and porosity, and therefore also the root effect, (D) Stimulates biological activities associated with vegetative growth, influencing the porosity of the soil, (E) More transpiration of water, leading to the subsequent drying out of the soil, (F) Insulation of the soil against high and low temperatures, (G) Compacting of underlying soil (Selby 1986, p.226). Vegetation also reduces the shear velocity of wind by imparting roughness to the flow of air (Morgan 1995 p.37). 15 3.1 Relationships between Land Use and Erosion Utilisation of land depends on different requirements with respect to land conditions. For a sustainable production basis, the land should be managed so that its production capacity is maintained or improved for future generations. When people get forced into the marginal lands for their survival or have special requirements on land not suitable for a certain kind of land use the matching with the characteristics and quality of land fails (Muhamud 1996, p.38). Changes in Land utilisation and erosion are strongly related and whenever land is misused consequences like accelerated soil loss is very common. The rate, spatial and temporal distribution of soil erosion depend on the interaction of physical and human circumstances and is therefore an integral part of both the natural and cultural environment (Morgan 1995, p. 6). Agricultural practices are of great significance in erosion. All operations reducing the vegetation cover, including cultivation, grazing and burning, logging and deforestation, road construction etc. increase the rate of erosion. Compared to cultivated land, grassland and forests seem to provide good protection against erosion. Overgrazing is no problem in the tropics but on soils lacking in humus, overcrowding on wet ground causes puddling and packing, increased sediment yield and runoff. Burning before the onset of intense rains also induces accelerated erosion. A consequence of clear cutting in many humid areas is a raised water table (Jansson 1982, pp.38-40). Soils play a central role in the effective operation of land use systems. The soil properties have great influence on the productivity of the land and are as well affecting the nature and timing of mechanical operations. The characteristics of the soil also have an impact on the behaviour of fertilisers and pesticides, and other related agricultural chemicals (Ellis & Mellor 1996, p.199).

3.2 Land Management and Soil Conservation Practices For a more permanently productivity, land should be used wisely within its capability. Economical stability, income, labour, educational level, culture, attitude, ownership of land and so on are important factors affecting the management of land, and therefore also conservation practices (Muhamud 1996, p.48). Crop and vegetation management is agronomic measures effectively used for soil conservation. The differences in density and morphology within the species will differ in their ability to protect the soil and reduce erosion. Several conservation measures is practised, such as rotation, cover crops, strip cropping, multiple cropping (Fig.7), high density cropping, mulching, revegetation and agroforestry (Morgan 1986, pp. 113-128). The correct choice of crops or vegetation mostly depends on physical essential elements such as soils and climate. The choice made must although take account of special requirements like financial factors as well. Sometimes a conversion to another kind of land utilization type gives more obvious financial advantages or disadvantages easily measured in money terms, other may be equally important in the long term, but more difficult to access financially (Davies et al. 1982, pp.102- 103). Strip cropping is a new method and not yet so very common conservation measurement on Java, but this method is considered to be a cheap and suitable management method with long protection and good effects, especially for runoff control, and as animal food. Another suitable alternative, as a cheap and easy conservation method against erosion and sedimentation, is alley cropping. Alley cropping is, according to the Department of Forestry, Yogyakarta especially useful on bench terraces in dryland cultivation's, and also contributes to

16 an increase of mulch and organic content. It is in addition to that useful as animal food and firewood. Soil management is another important strategy for erosion control, including application of organic content, tillage practices, and use of soil stabilisers (Morgan 1986 pp.130-135). According to Davies et al. (1982) soil management has two aims: to grow crops for profit and to maintain or improve soil fertility in the long term. The techniques used should increase the resistance of soil to erosion, and focus mainly on the improvement and maintenance of soil structure (Ellis & Mellor 1995, p. 248). A third strategy for erosion control is mechanical methods, which normally are in conjunction with agronomic measures. Mechanical techniques aim to reduce the energy of the eroding agent and often involve the modification of surface topography (Ellis & Mellor 1995 p. 249). Contouring, contour bunds, terraces, waterways, windbreaks, and other stabilisation structures are commonly used to fulfil this purpose (Morgan 1986, pp. 137-152). Agroforestry is a very common on Java. Research on Java has showed that the soil erosion rate is not significantly different between forests and agroforestry areas with the reason that crops and trees planted together in this way will have same conditions like a multilayered natural forest. Erosion measurements within a forest area usually show on low rates. Other researches has although indicated that the kinetic energy from the raindrops that usually is reduced by a high canopy tree will have time to reach more than 95% in speed in a free fall distance of eight meters. The drop size may also be increased through accumulation and falling from the leave surface. Severe erosion has also occurred within some teak plantations as a result of that (Kusumandari & Mitchell 1997, pp.376-380). Fig.7. Dryland with Multiple Cropping of a great various of species in the hilly areas, terraced wet paddy rice fields in

lower altitudes, Gunung Kidul (Photo M. Enryd 1998).

17 IV. RESEARCH PROCEDURES 1. Delineation of Scope of Work. This research was carried out from December 1997 until April 1998 in the regency of Sleman & Gunung Kidul in D.I.Y Yogyakarta, and can be divided into three phases, the data collection phase, the fieldwork phase, and the compile phase (completed in Göteborg during late spring and summer same year). Two study areas, with different land system, within the two regencies were chosen for comparison. The physiographic units of the complete study area are located along the southern slope of the Merapi volcano in the north-eastern part of the Sleman regency, stretching further down to the karstic plateau area of Wonosari, in the Gunung Kidul regency, finally reaching Baron in the coastal area. Great variations in the soil forming factors can be found in every physiographic unit between the slope of Mt. Merapi to Baron coast, especially due to topographic, lithologic and vegetation factors. In this respect influence on the soil development have given rise to distinctive distribution of soils within the study area.

2. Methods Since the overarching aim of this study is to investigate relationships between physical features and different land utilisation types, split into several miner purposes, following methods and material have been chosen for accomplishment of this study (see also Fig.8 Flowchart over the Operational Steps within the Research on p.19).

2.1 Data Collection Phase The first step of the research included many visits to different departments, offices, faculty's etc. for textural and spatial background material about the area of concern including: a) Collection of literature, maps, satellite images about physiographic conditions, land utilisation types, statistic data of demography, socio-economic and cultural conditions, and other secondary data used as theoretical background information, and for the planning of the research. b) Preparation of fieldwork by delimitation of the research area, field orientation, and formulation of questionnaires for interviews.

2.2 Fieldwork Phase During fieldwork a survey method was used, consisting of soil sampling, soil profile descriptions, and interviews with the local people about the socio-economic and physiographical conditions in the area (for questionnaire see app. 4. p.68). The survey spots were chosen based on primary data, Dr. Ir. Agus Setyarso. M.Sc., and field observations as to be representative for the surrounding areas with similar conditions. Following procedures and material were used during the fieldwork: a) Land use map (Penggunaan tanah, Propinsi D.I.Y, 1994/95, scale 1:100 000), and GPS (Magellan Nav 5000) were used for orientation and determination of position for each survey site. The altitude was then noted with the help of an altimeter. b) Soil profile descriptions was carried out with the help of the Munsell colour chart, together with a survey sheet (app.6, p.70) used for description of the physical and chemical soil properties. The soil profile description included 6 of the total 13 sample sites. (For more detailed information see the section Profile description on p.40). c) Totally, a number of 26 soil samples were taken from different depth, usually at a depth of 5 cm, 50 cm, and from the subsoil, if possible by drilling or digging. Soil samples taken from 18 sites without soil profile description were carried out in an adjoining area, with another kind of land utilisation type. This was done in order to compare areas with different kind of land use located within the same LMU, and also be able to find possible relationships between soils and land utilization type. Determination of pH was then made from all sites by the use of a pH-indicator (0-14) put into a solution of soil and distillate water (1+4). Colour and other characteristics of the soil were then noted using same survey sheet as for the soil profile description. d) Shear strength tests were taken from 3 different depth (5 cm, 50 cm, and from the subsoil, if possible whenever a soil profile description was carried out. This with the aim to measure the cohesion of the soil. ELE International Torvane soil test was used for this matter. e) Measurement of the infiltration was the carried out with the help of an infiltrometer consisting of an inner and outer steel cylinder ring with the 6,8 cm respective 11,8 in wide, and 13,1 in height. A plastic can with the volume of 3 Litre was also used. The infiltration rate was the noted for every minute until no water was left in the can, which varied a lot between the different survey sites. The position of the infiltrometer was in connection with the sampling site, and also 15 m above respectively below the site in the slope for more references. f) With help of a measuring tape, a radius of 15 m was taken out in the surrounding area around the soil sample site, as to be representative for a certain land utilization type within the land unit, classified by RePPProT (1989). The relative relief, local climate, type and density of the vegetation and ground cover were then determined in detail with the help of my talented field assistants, Ari Susanti and Wijonarko Suhari, from the Faculty of Forestry, Gadjah Mada University, Yogyakarta, and also by the very courteous local farmers. Other field checks concerning above described matters was also carried out to make sure that the surrounding area with same kind of land use had similar conditions as the sampling site. g) Slope inclination and slope aspect was measured by the use of a Suunto and a compass. h) The degree of erosion and other visible land degradation, if any was noted and classified according to the survey sheet (app.5, p.70). i) Land management was observed concerning crop and vegetation management, soil management and mechanical methods. Interviews was carried out with the help of questionnaires and interpretation by Ari Susanti and Wijonarko Suhari (app.4, p.68) among 30 random chosen farmers of different age and sex, and also with other people that have local knowledge about the study area. The questions concerned socio-economic, cultural and land conditions for farmers with different land utilization types, and had an important function as a base for the fulfilment of the result section.

2.3 Compile Phase The third phase embraced several kind of data analysis, including soil analysis carried out at the Department of Soil Science, Gadjah Mada University. Another software used was Ilwis, a GIS program for digitalisation and creation of maps (For a more detailed description about the application of GIS on p.20). To fulfil some of these maps, estimation and evaluation of the land capability and erosion hazards with the help of USLE was necessary. Questionnaires and other data were then analysed as a further step towards the final compile of the essay.

19 Statement of the Problem Determination & Research Scope of Work Limitation of Planning Questionnaries Research Process

Attribute Data Field Selection of the Physical Observation Data Identification Study Area Social Cultural Demographical Economical Technological

Data Collection

Field Work Erosion Hazard Mapping Soil Sampling Soil Profile Description Textural Interviews with Farmer etc Primary Data Secondary Data Spatial Description of Land Characteristics

Data Arrangement

USLE- Textural Soil Analysis GIS Calculations

Compile of Research

Fig.8. Flowchart over the Operational Steps within the Research.

20 2.4 The Application of GIS In order to evaluate the land capability of the study area the GIS-program Ilwis 1.4 was used as a convenient tool for that fulfilment. Ilwis (Integrated Land and Water Information System) is a GIS-software that integrates image processing and spatial analysis capabilities, tabular databases and conventional GIS characteristics. Data acquisition from aerospace images is also enabling effective monitoring (ITC 1993). This software is a common tool used especially for land use planning in Indonesia. Due to time limit a total number of 8 maps over different physical features within the study area were digitalized with the intention to let the land capability depend on so many factors as possible (See further fig.9). Scoring, concerning high potential erosion hazard, of the land characteristics was then carried out. Furthermore, the scoring tabular were linked together with the digitalized maps, and an overlay of all maps showing high potential erosion hazard areas resulted in a high potential erosion map. An overlay with the land use map were done in order to get a more clearly map indicating high potential erosion hazard within the different types of land use. Matching between this map and the erosion hazard map (made during the fieldwork phase) were further carried out, finally resulting in a land capability map after an overlay. Since the land capability map almost is a result of map studies a further purpose with the GIS application was to create a recommendation map for forest land use (Fig.10), partly based on my own data collected during fieldwork. An administrative map over the study area were digitalized together with two (by me modified) erosion hazard maps made by RePPProT (Land System with Land Suitability & Environmental Hazards, Sheet Jawa 1407, Jawa 1408 1989), and an already existing forest land use map (TGHK) made by the Department of Forestry D.I.Y. (1992). After an overlay between these three maps, matching between the forest land use map and the erosion hazard map were done with the purpose to exclude areas for conservation. The remaining areas showed on the map were then overlaid with a soil loss map, created from USLE-calculations based on the field data. This resulted in the split up in two categories, high and low potential erosion hazard areas, within the study area. Areas with high potential erosion hazard were considered to be most suitable for reforestation and afforestation. The low potential areas were all regarded as productive, and therefore a further split including non-forest respective forest areas were done. Finally, an overlay between productive-non forest areas, production forest, and conservation forest was carried out resulting in a recommendation map for forest land use within the study area.

21 Digitalisation Maps of Physical Features of Maps Geomorphology Scoring of Slope Land Rainfall Characteristics Soil -High Potential Groundwater Erosion Hazard Land Use Erosion Hazard Map

Scoring Data Linkage Digitalisated Tabular Maps

Overlay

High Potential Erosion Hazard Map

Land Use Overlay Map

Land Use Map with High Potential Erosion Hazard

Erosion Matching Hazard Map

Overlay

Land Capability Map

Fig.9. Flowchart over the Operational Steps for Creation of the Land Capability Map

22 23 Digitalisation Adminitrative Map of Maps Erosion Hazard Map Forest Land Use Map (TGHK)

Administrative Map Overlay Erosion Hazard Map

Erosion Hazard Map with Administrative Details

Forest Land Use Map Overlay (TGHK)

Forest Land Matching Use Map Erosion Hazard Map (TGHK)

Remaining Conservation Area Area

Overlay USLE-Map

Low Potential High Potential Hazard Hazard

Reforestation Production & Afforestation

Yes

Area for Production

Non Forest Forest

Area for Forest Overlay Conservation Forest

Recommendation Map for Forest Land Use

Fig.10. Flowchart over the Operational Steps for Creation of the Recommended Land Use Map

24 V. RESULTS

1. The Study Area This part of the thesis will be a closer presentation of the study area, located in the regency of Sleman respective regency of Gunung Kidul (Fig.11a). These two areas will be introduced separately but in direct connection to each other. This is done for a better comparison and also for a more integrated context. Finally, a more detailed summary in tabular form over the physical features respective population status will also be presented in the end of this section. This section of the results mainly is based on interviews with farmers made during fieldwork. Furthermore it is also supported by interviews with people educated within the frame of this research as well as with more detailed and specific data taken from other literature sources and maps, than presented earlier in the overview of the special province. Note that Fig.11b shows a larger area than the actual sampling area (Fig.11c). The reason of that is to give a better overview as a way to simplify for further understanding of the origin of different physical features. This area is mainly based on field observations, together with RePPPtoT's LMU-mapping from 1989, but also with the support of different maps.

Fig.11a,b, c. Geographical Overview of the Study Area.

The numbers within map b is the elevation in m.a.s.l. The names in the same map show some sub-districts as well as larger rivers within the study area.

(Source: Peta Fisiografi. Propinsi D.I.Y., scale: 1: 250.000, Mitojat dkk (1987)).

The Sleman regency, with a total area of 574.82 km2, is located north to Northeast of D.I.Yogyakarta between 7° 30' to 7° 50 ' S, and 3° 25' to 3° 45' E.

25 Stretching from south to Southeast within the special province, enclosing a total area of 148.536 km2, is the regency of Gunung Kidul between 7° 50' to 8° 10' S, and 3° 10' to 4' E. It is bordered by the Sleman regency in the Northwest (Fig.11a) but embrace totally different physical conditions.

1.1 Physical Features The regency of Sleman is strongly influenced by volcanic activity, and due to eruptions of the Merapi volcano, the landscape has continually altered over time, and greatly influences the soil types and patterns. Eruptions have occurred several times during recent years and the latest big eruption was at 22 November 1994. Freshly erupted materials accumulated near the volcanic cone as a debris avalanche. During heavy rainstorms, the unconsolidated and very hot material from the volcanic slope flowed down as lahar, or 'glowing avalanche' with a velocity of about 300 km/h as far as 7 km from the summit burning everything in its path (Sudibyakto & Abasi

1996). Fig.12. Geomorphology Map of the study area (Source:Peta Geomorphology.D.I.Y. Scale 1:250.000 Laboratorium Kartografi, Fakulats Geografi, Universitas Gadjah Mada (1990)

The parent material within the area is of volcanic origin with a relative homogenous composition (Tab.1, p.31 ). Morphologically, the regency is divided into 5 units: the cone, the upper slope, the middle slope, the foot plain and the alluvial plain area (Fig.12).

The regency of Gunung Kidul is mostly located in a karstic area and has a more heterogeneous composition of parent material, dominated by limestone and marl (Tab.1). The north to Northwest part of the regency, bordering the Sleman regency, is influenced by material of volcanic origin. Further south a mix of sandstone, volcanic and limestone material can be found, finally more south reaching the large limestone and marl area. The regency is generally hilly from north to south, as a result from land upheaving. Due to the fault and flexure occurring, basins were formed, and within the basins a flat to undulating karstic 26 plain area can be found. Erosion and solution processes then formed a negative topography or depression. Alluvial deposits forming a karstic alluvial plain later filled the depression (Sutikno 1996 p.8). A huge gently to strongly undulating karstic plateau area, the Wonosari plateau, is located in the centre of the regency. The karstic features of the area are characterised by karstic dome hills, dolines, uvalas, underground rivers and caves with stalactite/stalagmite (Tab.1, p.31).

The volcanic slope of Mt. Merapi, reaching an altitude of 2911 m.a.s.l. at the cone dominates the topography in the northern part of the regency. A large plain area is located in the south to Southeast. The southern slope of the volcano has very steep areas within especially the nearness of the cone, but also on the upper slope (Fig.13). The continuing slope below is then gradually decreasing in angle, finally reaching the plain area. Approximately 25% of the area vary between 100-500 m.a.s.l. (Tab.1) and the rest of the land are almost equally divided into areas below 100 m.a.s.l. respective areas between 500- 1,000 m.a.s.l. Fig. 13. Slope Map of the Study Area Source: Peta Kemampuan Tanah Prop. D.I.Y, scale1: 100.000, Kanwil Badan Pertanahan Nasional. Prop. D.I.Yogyakarta 1994/95).

In the regency of Gunung Kidul, the steepest areas are concentrated to the hilly parts in south to Southwest. Although, some areas in the northern part of the regency among limestone ridges is also very steep. The Wonosari plateau in the centre is rather flack with surrounding steep areas (Fig.13). Areas with an altitude between 100-500 m.a.s.l. dominate within the regency covering about 90% of the land areal. Other areas are located below 100 m.a.s.l. in altitude, with exemptions of some few areas having an elevation that varies between 500-1,000 m.a.s.l. (Suharsono et al. 1996, p.8).

The climate within the volcanic area is characterised by a mean monthly temperature varying from approximately 25°C to 28°C (BPS, Kantor Statistik, Kabupaten Sleman Dalam Angka 1996). The mean annual precipitation shows on a high amount of rainfall at the cone (Fig.14), and also on a relative gradually decrease in amount of rainfall with altitude further down the slope.

The relative humidity is high, reaching about 78 %, and during the rain season an increase with 10% is normal. A decrease in sunshine duration (0.00 a.m. to 04.00 p.m.) with 15 -20 % to about 45% is also usual at this time of the year (Woro 1990, p.28). The

27 Mean monthly temperature within the regency of Gunung Kidul is approximately 26 °C, which is a little bit, less than the plateau unit (see Tab.1). The mean annual precipitation is varying on a relative local scale between 2.000-4.000 mm. In general the north part of the regency have a few 100 mm less rain a year than the coastal south, and the plateau in turn receive a few 100 mm less than the northern part. (Woro 1990, p.28). The mean monthly humidity is also a few percent higher than the northern part, reaching almost 90%. The coastal Zone in the very south is although exceeding this rate with a few percent (RePPProT 1989).

Fig.14. Rainfall Map of the Study Area. (Source:Pola Curah hujan prop. D.I.Y Scale: 1:100.000. Dinas Pertanian dan Dinas Pengairan Kabupaten Dati II se Prop. D.I.Y (1982/92))

The vegetation in some parts of the Sleman regency is not more than 3 years old because of 'glowing avalanches'. On the steep upper volcanic slope, considered as the dangerous zone, a thick natural forest conservation area with growing tree species like pine, salak and rattan (app.5, p.70) can be found. Dryland forest dominates further down on the upper to middle slope, containing a varying mix off species. Large areas of irrigated paddy rice are located on the middle slope down to the foot plain (Fig.15). Wetland cultivation, especially paddy rice also dominates on the alluvial plain area together with maize. Compared with the other regencies, Sleman has less dryland and wetland dominates in the regency (see D.I.Yogyakarta section), with approximately 43 % of the total land area covered by irrigated paddy rice (Fig.19, p.32). This is in general also the only land utilisation type used in the wetland areas of Sleman (Fig.15). Home garden is the most common land utilisation type in the dryland areas followed by dryfields or garden. Areas covered with forests or forested lands are much more unusual compared with the other regencies within the special province, only comprehensive an area of about 4 %.

Gunung Kidul is the most forested regency within the special province with about 43% of the total land area covered by dense forests and forest lands (Fig.20, p.32). The most common tree species is shown in Tab.1.

28 Acacia is used very frequent especially in the more hilly areas were community forests has been created as a way to promote revegetation programs (Oral Setyarso 1998). Compared with the Sleman regency, cultivation with paddy rice is rare, only comprehensive about 4% of the land use in the area (Fig.20). It is usually the more steeply slopes, located in the low altitude areas within the regency that are cultivated with paddy rice and maize. Dryland forest, rich in species, is the most common land utilisation type, covering approximately 55% of the regency (BPS Fig.15. Land Use within the Study Area (Source:Penggunaan Kantor Statistik D.I.Y. 1996).tanah, Propinsi D.I.Y, scale 1:100. 000 (1994/95) & Field Mapping 1998). . Regosols, with its origin from the volcanic parent material, dominates on the volcanic slope (Fig.16). The soil usually with a soil depth of 1-2 m or more, is very fertile and has a high porosity, which makes it suitable for cultivation (for detailed information see the section Soil Characteristics on p 42). Coarser material was deposited upslope, and the finer material was transported to lower parts. Therefore, soils with finer texture are find on an increasing distance Fig.16. Soil Map of the Study Area (source: Jenis Tanah Kabupaten from the volcanic cone. DATI II Gunung Kidul. Scale 1:100.000 (1988/89), Jenis Tanah Kabupaten DATI II Sleman. Scale 1:50.000 (1989/90), Penggunaan Tanah DATI II Gunung Kidul. Scale 1:100.000 (1988/89), Penggunaan Tanah DATI II Sleman. Scale 1:50.000 (1991/92)). PPT-Indonesian Soil Classification System

Cambisols dominates further down on the fluvial plain area at the volcanic foot, with a rather deep soil depth in places receiving deposits from the slope above. Combined with rather shallow groundwater various wetland crops can be cultivated in this area with great success. The soil distribution within the regency of Gunung Kidul is very varying, mostly consisting of low drainage and more acid litosols and luvisols, with exception for the karstic plateau of Wonosari, located in the central part of the area. Vertisols, litosols and rendzina dominate in this area

29 (Fig.16). In general, the soils within the regency are low in fertility, especially in south, with a very shallow soil depth varying between approximately 10-30 cm. An exemption is the more fertile areas at the border to the Sleman regency, having a soil depth of more than 1 m (Fig.17) because of volcanic influences (for more information see the section Soil Characteristics on p. 42).

Fig.17. Orange coloured Soil Deposits dominates the Landscape in Patuk, Gunung Kidul. (Photo M. Enryd 1998)

Fig.18. Groundwater Map. Peta Airtanah D.I.Y. Scale 1:250.000 Laboratorium Kartografi, Fakultas Geografi, Universitas Gadjah Mada. Yogyakarta).

The river systems of Merapi consist of Progo, Dengkeng, and Opak river system. During the eruption of Merapi in 1994, Boyong river, which is under the Opak system received huge

30 quantities of volcanic material and played a very big role in the distribution of various volcanic material in form of Lahore or mudflows that occurred after heavy rainfall (Sudibyakto & Abasi 1996, p.2). As a consequence, river water was generally polluted to such an extent that it was unfit for any use. The groundwater depth on the long slope is approximately 7-15 m, with exemptions for the non-aquifer cone and upper slope, and the fluvial foot plain with a depth of more than 25 m (Fig.18). The Oyo river is running through the regency of Gunung Kidul with a west to Southwest direction causing occasionally flooding, and therefore also erosion in the catchment areas. The underwater rivers and the relative shallow groundwater with a depth less than 7 m that can be found in especially the more central parts of the regency (Fig.18) are of great importance for water supply to the local cultivation, and many wells therefore exists within that area.

1.2 Population Status The Sleman regency is administratively divided into 17 sub-districts, including a total of 86 villages. Sleman has the highest population density of all the regencies within the special province, and is also in possession of the highest population growth (see the D.I.Yogyakarta section Socio-economic & Cultural Parameters). Approximately 25% of the total population also live within this regency, of which about half are concentrated in the more urban areas (BPS, Kantor Statistik Kabupaten Sleman 1996). The regency of Gunung Kidul is divided into 15 sub-districts, including a total of 144 villages, in which about 23% of the total population within the special province lives. It is also the most rural regency with only approximately 4% of its population living in more urban areas (Tab.2, p.31). The population density is lower compared with the other regencies, which also is the case for the population growth that is about 50% less (BPS, Kantor Statistik Kabupaten Gunung Kidul 1996). The economical situation in the regency of Sleman is relative good compared with the other 3 regencies because of the more fertile soil. Most of the land in Sleman is highly productive and, according to the interviews and other field data, it also indicates on an increase in productivity of the cultivation with none to slight erosion for most of the farmers. This affects the economical profits for the households and an approximately income is as a result between Rp.500.000-1.000.000 (60-120 US) a year which is 3-10 times more than for a household located in a karstic area of Gunung Kidul. Although, a low-paid side-income selling food crops in the city, work as a shepherd or own a small shop in the village is very common among farmers. One household usually comprises of about 4-6 people in Sleman, compared with 5-8 in Gunung Kidul, cultivates a land area of approximately 0.2-1.5 ha which, according to the interviews, and is the regular size within the whole study area. The nearness to the active volcano have also given the result that areas have been converted to conservation forest and tourist areas, providing the local people with some extra income. People seem to have no problem with erosion or other degradation of their land, but figures based on the TP-formula (app.2, p.67) although indicates on an increasing population pressure within the regency. Opposite the situation occurring in the Sleman regency most people within the regency of Gunung Kidul, according to the interviews, have problem with erosion, and other land degradation resulting in a decreasing in productivity. This is affecting their economy and poor villages have been priority for community forests. Community forests serve the local people with fire wood, fruits, vegetables, food for the animal's etc. It is also of cultural importance, providing the people with many kinds of species used for different ceremonies and traditional medicine (Oral Setyarso 1998).

31 People living near the privet research forest Wanagama in Wonosari, owned by Gadjah Mada University, also have the privilege to bring firewood from the forest. In return they usually provide the research area with dung from their animals and therefore also contribute to the maintenance of the forest. There is also some kayu putih forest plantations owned by the government within Gunung Kidul. Some farmers work extra within these areas and can therefore make some economical profits by collecting the leaves from the tree that contains valuable resources of oil used in medicine. The economic situation for the farmers in Gunung Kidul varies mostly depending on if the cultivation is located on the volcanic soil as a dominant factor. Most of the land area is although located in less fertile areas and the farmers are working hard for its survival without any special economical profits. The economical situation also tends to get worse since the majority of all interviewed farmers complained about a decrease in production, and in some cases also about more erosion. The majority of the people does not know the reason of that, or can not do anything about the occurring situation because of limitation in their economy. The lifestyle in the villages is simple but all farmers' claims that they have enough of money to support their household, and that they are relative satisfied with their social and economic situation.

1.3. Summary of Results 32 Tab.1. Physical Features within the study Area. Physical Sleman Gunung Kidul Features Geology Old Volcanic Deposits: basalt containing Andesite, breccia, sandstone, tuff, augite-hyperstene, hornblende, andesite limestone, marl Young Volcanic Deposits: augite, hyperstene andesite Morphology Volcanic Slope. Karstic features: Plateau, dome hills, dolines, uvala, underground rivers, stalactite/stalagmite caves, ridges Elevation 6.203 ha (11%) <100 m.a.s.l. 43.246 ha 11.515 ha (8%) <100 m.a.s.l. 1134.171 ha (75%) 100-500 m.a.s.l., 6.538 ha (11%) (90%) 100-500 m.a.s.l., 2.850 ha (2%) 500- 500-1000 m.a.s.l., 1.495 ha (3%) >1000. 1000 m.a.s.l. Top of Merapi: 2911 m.a.s.l. Steepness Cone: >40%, Upper slope:15-40% (also Hills in S-SW, N: >40%, S-SW, N: 15-40%, >40%), Middle slope: 2-15%, Foot plain 0- N-NW-2-15%, plateau: 0-2% 2% Climate: Am North:Am, plateau:Aw Rainfall (mm) Mean Annual:4.500-3.000 cone & upper Mean annual in plateau:2.073 (1500-2000), slope, 3-2.500 middle slope, 2.000-1.500 Remaining areas 2-2.500 foot plain Temperature(0C) Mean Monthly: 25-28 Mean monthly: 26.35 Humidity (%) 78%(Sept)-86%(Jan) Mean: 87.23 Land Use Homogenous: Cone: Conservation Forest, Heterogeneous: NW (low altitude):wet Upper slope: Dryland, Middle slope to plain: paddy rice, forest: plateau and adjoining wet paddy rice areas, Dryland: remaining area Soils*(USDA): Entisols & Inceptisols Entisols, also alfisols & vertisols in plateau Hydrology: Opak river, Shallow perennial rivers. Oyo river, Shallow perennial rivers. Groundwater depth: non-aquifer at cone, Groundwater depth: N-NW, S, parts of upper slope:15-25 m, middle-foot plain:7- plateau: non aquifer, south part of 15m plateau:>25m,

Tab. 2. Population Status within the Study Area Population Status Sleman Gunung Kidul

Population (thousands) 804.4 729.7 Male population (%) 49.3 48.9 Female population (%) 50.7 51.1 Urban Population (%) 48.2 3.8 Rural Population (%) 51.8 96.2 Population Density (thousands per km2) 1.399.34 491.2 Population Growth (%) 1.27 0.68 Annual average income per household 60-120 25-35 (farmers)in $US

33 Fig.19. The distribution of Land Utilisation Types in the Sleman Regency (1996). (Source: BPS, Kantor Statistik D.I.Y. 1996.)

Fig.20. The Distribution of Land Utilisation Types in the Gunung Kidul Regency (1996) (Source: BPS, Kantor Statistik D.I.Y. 1996.)

2. The Area of Focus

34 The first part of this section is based on analysis and observations made during the fieldwork phase together with theoretical background information about the sampling sites (Fig.21). The study area is divided into different land mapping units showed in Fig.22. Land Mapping Units within the study Area below and a unit usually include more than one land utilization type. Therefore, sampling sites where chosen as to be representative for each land utilization type within every Land Mapping Unit. Furthermore, section 2.2. Soil Characteristics, a more detailed description of the soil properties, is a result of soil laboratory analysis and other data collected in field.

Fig.21. Map of Sampling Sites

Site 1. Hutan Wisata, Kaliurang, Sleman (Conservation Forest) Site 2. Turgo, Kaliurang, Sleman (Dryland Cultivation) Site 3. Agro Wisata, Turi, Sleman (Dryland Cultivation) Site 4. Batur, Cangrigan, Sleman (Dryland Cultivation) Site 5. Ngemplak Asem, Ngemplak, Sleman (Wet Paddy Rice Field) Site 6. Gemawang Putat, Patuk, Gunung Kidul (Dryland Cultivation) Site 7. Gemawang Putat, Patuk, Gunung Kidul (Wet Paddy Rice Field) Site 8. Forest Police Resort, Playen, Gunung Kidul (Forest) Site 9. Keduriggereis, N'glipar, Gunung Kidul (Forest) Site 10.Department of Forestry-Forest Research, N'gleri, Gunung Kidul (Forest) Site 11.Wanagama, Gadjah Mada University Research Forest P5, Wonosari, Gunung Kidul (Forest) Site 12.Wanagama, Gadjah Mada University Research Forest P17, Wonosari, Gunung Kidul (Forest) Site 13.Palang Racuk, Baron, Gunung Kidul (Dryland-'Bushland')

35 Fig.22. Land Mapping Units within the Study Area (Source: Jawa Sheet 1408 Yogyakarta. Land Systems/Land Suitability. Land Systems with Land Suitability & Environmental Hazards. Scale 1:250.000. Serie RePPProT (1989) & Jawa Sheet 1407 Parangtritis.Land Systems/Land Suitability. Land Systems with Land Suitability & Environmental Hazards. Scale 1:250.000. Serie RePPProT (1989)

2.1 Sampling Sites This section will be a closer presentation about the physical features of the totally 13 sampling sites (Tab.4, p.35). Soil profile descriptions, almost taken on a strait diagonal line from north to south were also carried out from 7 of the sampling sites with the purpose to describe a toposequence, or catena (see further Soil profile Description below). Remaining 6 sites were taken from the adjoining area of each profile site comprising another kind of land utilisation type (see Fig. 21). Starting from the north part of the study area is sampling site 1, the conservation forest, located on the cone of Merapi. The thick vegetation that mostly consists of pine and zalucca is about 3 years old as a result of the eruption in November 1994. Even if the vegetation layer has a high density, evidence of slides are common. During the rain season that occurred at the time of the fieldwork, more slides were noted (Fig.23). The terrain is very steep, reaching more than 45 degree at the sampling site.

36 37 Fig.23. Landslides along the Volcanic Cone. (Photo M. Enryd 1998) This conservation forest attracts many tourists with the interest to see the active volcano, but the area was recently (July 1998) evacuated because of an expected eruption. Within the very porous and granular soil stones with its origin from earlier eruptions are found through the whole profile (for more details about the soil profile see Soil Profile Description on p.40).

Site 2, located in Turgo a few kilometres Southwest of the conservation forest belongs to another LMU. This dryland area was also affected by the 1994 eruption and therefore the vegetation is young. Some native species like kaliandra and sengon is cultivated, and also coffee. Elephant grass dominates on the ground together with large volcanic blocks in the only slight sloping area. The soil depth is only 40 cm but appears to be very fertile, and no visible evidence of soil degradation occurs.

Fig. 24. Wet Paddy Rice Field in Turi, Sleman (Not a Sampling Site) (Photo M. Enryd 1998)

38 Next LMU includes 3 sampling sites (3, 4, 5) along the middle to foot slope. Site 3 is a large tourist area cultivated with salak pondoh, a native fruit tree. The area is flat and its position is located more to the west than the other sites that is following the steeper southern slope of Merapi. The cultivation is supported by a local groundwater source and is, according to the managers, very productive. Site 4 also includes dryland, but its position on the Southeast slope comprises a more steep topography than site 3 mentioned above. The age of the cultivation is unknown and has a big variety of species, such as melinjo, avocado and cassava. The area contains terraces of more than 1 m in height, with local stones in the top layer. The soil is about 1 m in depth and its structure and other characteristics indicate on very fertile conditions. Although some soil loss has been noted within the area by the local farmers. A small and young irrigated paddy rice field in the volcanic foot area encloses site 5, which is a converted fishpond since in December 1997. Since the cultivation is located in a flat area, because of terracing, no erosion is found and the soil depth is more shallow compared with site 4, but similar conditions concerning the visible soil characteristics occurs (Fig.24).

Sampling site 6 will represent next LMU. Still located along the foot slope is site 6, the most various sampling area, comprising a dryland cultivation of unknown age with a random mix of species like cacao, melinjo, maize, sengon, rambutan, coffee and banana trees. The cultivation is terraced with the same technical used for the earlier mentioned site 4. The degree of the slope is although more steep varying from 9 to 250 on a 30 m distance between the lower and upper measuring point. This LMU contain a more various lithology of volcanic and sedimentary origin, also including a mixed mineralogy of intermediate, basic and calcareous material. The very bright orange to reddish coloured soil with a depth of more than 150 cm has visible soil characteristics that indicates on good growing conditions for the vegetation. The owner of the land although complains about an ongoing increase of soil loss through runoff since a few years back in time.

Fig.25. Mud Cracking in Patuk. (Photo M. Enryd 1998)

Samples were also taken from a LMU comprising a terraced wet paddy rice field (site 7), located further south to Southwest on a moderately, dissected, tilted plateau. The composition

39 of the lithology and mineralogy is similar as described above, and soil conditions seem to be favourable for the cultivation. The rice fields position in direct nearness of a river also makes advantageous conditions for irrigation. The more sparsely precipitation that occurs within this area although gives rise to mud cracks direct outside the rice field (fig.25).

A miner LMU, including site 8, also with its position on the tilted plateau is located less than 1 km south of Opak River. The area is forested with species like mahogany, acacia, and teakwood growing on a calcareous ground. It is not a very steep area but small slides, and gullies were although found within this area. Within the 32 cm thick soil profile transformation of iron to ferric material and formation of calcretes is distinct. The incorporation of the bedrock within the highly weathered profile also creates aggregates through the accumulation of calcium carbonate, and therefore the drainage is very high resulting in even more weathering especially occurring during rain season.

From a rather hilly area, located on the karstic Wonosari plateau, 3 sampling sites were chosen (site 9,10,11) as to be representative for next LMU. Site 9 and 10 are since a few years back in time converted teak plantations cultivated on calcic ground. The productivity is according to the farmers lower now after the change to kayu putih, a tree used for the making of natural medicine. These two forest areas, located above a flood plain, have seasonally flooding from the same river at the end of the slope. The slopes is moderately steep, but the low quality limestone terraces as well as the low density of trees is hardly preventing runoff, which makes these 2 areas highly eroded (Fig.26).

Fig.26. Eroded Kayu Putih Cultivation (Photo M. Enryd 1998)

The soil depth is very thin only comprising 12 respective 7 cm, and even if the structure consists of single grains for site 9, and aggregates for site 10 the drainage is moderate to low because of saturated conditions.

Site 11 is part of the Gadjah Mada forest research also positioned on calcareous ground on the hilly karstic plateau. The thick forest embraces species such as teakwood and lamtoro (local

40 firewood), and has a function as community forest. The forestland is terraced but its position on the moderately slope still give rise to small slides. The depth of the soil is 15 cm, and consists of ferric material and accumulation of calcium carbonate within the profile. The structure is granular and porosity and drainage conditions are relative favourable. Revegetation programmes have since the early 70´s been practised here and in surrounding areas, some has resulted in success others with failure without any particular known reason. The reforestation programme included among one thing the introduction of new and more tolerant species, and hilly areas were usually prioress for forest. Site 12 is also part of the Gadjah Mada forest research, however in another LMU. This is a eucalyptus forest, planted in rows along a slightly sloping area. No apparent erosion is visible and the soil conditions also seem to make advantageous conditions for cultivation of this kind. The soil depth is although only 10 cm. The last LMU includes site 13 (Baron), an extremely eroded hilly karst area in the coastal zone. The slopes are sparsely covered with vegetation and only bushes with a very superficial root system together with grass manage to survive in the hardly existing soil layer along the slopes. In the plain areas between the slopes cultivation with maize is common. The low quality limestone terraces are hardly visible among all different salient calcic formations (Fig.27). The reddish brown soil at the sampling site has a depth of 20 cm at the sampling site. Visible conditions within the soil indicate on bad conditions, such as very low drainage, low porosity etc. and evidence of erosion by both wind and water is obvious. Fig.27. Calcic Ground in Baron (Photo M. Enryd 1998)

Soil Profile Description External factors like volcanic eruptions has from time to time dramatic changed the patterns among the slope influencing the soil formation by the burial of already existing soils in north.

41 The areas in south are instead strongly affected by degradation due to chemical and physical processes occurring in the calcic parent material. The cross-section contains some further information about the soil profiles within the study area than presented in the former section, and falls under a typical description of a catena, concerning geomorphic processes occurring among the slope.

Fig.28. Soil Profiles within the Study Area. General Description Profile 1: Volcanic Influenced. Mineral horizons with diffuse boundaries. Gradually colour change to approximately ~50 cm (dark brown-brown). Volcanic stones within the whole profile. Moderate Shear Strength. Profile 2: Volcanic Influenced. Mineral horizons with diffuse boundaries. Gradually colour change to approximately ~50 cm (dark brown-brown). More volcanic stones after ~50 cm. Low shear strength. Profile 3: Volcanic Influenced. Eluvial horizons mottled gley until ~45 cm. Calcic accumulation until ~50cm. Darker red colour at a depth of 100 cm. Subsoil at unknown depth (>150 cm). Moderate shear strength. Profile 4: Weathered calcic profile. Mottled until ~25cm with a mix of organic matter until ~15cm. Calcretes and within the whole profile, mostly concentrated on ~15cm from the surface. Thin profile (32cm), moderate shear strength. Profile 5: Very thin and calcic profile (7 cm). Calcic and ferric accumulations. Shear strength test not accurate. Profile 6: Very thin calcic profile (15 cm) with organic matter until ~5 cm. Calcic accumulations make soil unconsolidated. Profile 7: Very thin profile (12 cm). Brown red soil with incorporated calcic bedrock. Shear strength test not accurate.

42 2.2 Soil Characteristics

43 Totally, 15 different laboratory analysis from each soil sample was carried out from every sampling site in order to give a more detailed analysis of the physical and chemical features of the soil (Tab.5). A summary of the analysis pointing out the most distinguishing features within each sampling site in comparison with other studies will now be presented together with some theoretical comments. · The texture along the slope of Merapi is coarse with sandy loam to loamy silt at the cone and upper slope. Further down sandy soils occurs as a result of water transfer. Clayey material dominates in the regency of Gunung Kidul. · The amount of exchangeable potassium is in general low within the whole study area, with exception for site 6, Gemawang Patuk (dryland). Potassium as well as magnesium belongs to the clay minerals and is according to Rowell (1994) usually occurring in higher amounts within soils formed on sedimentary material, which also is the case. The lack of potassium, especially occurring along the Merapi slope, may be a result of leaching. Fertilisers are also frequently used, which in a large concentration can reverse the effect, causing the potassium to be non-exchangeable (Rowell 1994, p.177). Losses also seem too large in more acid and coarse-textured soils (Armson 1979, p.134) that occur along the slope. Site 6, with high amount of potassium, is located on the foot plain of Merapi receiving large quantities of the very minerogen volcanic soil transported downslope. · Exchangeable calcium in the Sleman soils is moderate, while sites in Gunung Kidul have substantial higher amount. This is very distinct due to the difference in lithology between the two regencies. · The presence of exchangeable magnesium is low on the Merapi slope, and moderate in the Gunung Kidul sites. Although Site 6 & 7, located in Gemawang Patuk on the foot plain, have significant higher amount of magnesium. Leaching processes occurring on the slope could, as well as for the higher potassium conditions earlier mentioned for the Patuk area, give rise to the higher amount of magnesium. Excessive amount of potassium also reduce the uptake of magnesium (Davies, et al. 1982, p.42), and in addition to this these soils have clayey texture together with sesquioxides which contributes to the held of exchangeable cations (Rowell 1994, p.176). Magnesium occurs together with calcium in dolomite (Armson 1979, p.134), but on lime-rich soils calcium is antagonistic to magnesium (Davies et al. 1982, p.42) which could be the case for the soils located in the calcic regency of Gunung Kidul. · Exchangeable sodium values are considerable higher in sites located in Gunung Kidul. The low amount of sodium in the volcanic slope is increasing further down, and since sodium is lost through leaching more easily than other cations it could be the case. Sodium can be toxic to many plants species, and it also has a deleterious effect on soil structure, promoting the dispersal of aggregates (Ellis & Mellor 1995, p.49), although calcium protects the soil from deterioration, and also defends plants against the toxic effects (Rowell 1994, p.280). This to a certain limit and in order to evaluate if sodic conditions occurs, calculations with the Sodium Adsorption Ratio (SAR) formula was necessary to fulfil this. SAR represents the total amount of exchangeable sodium relative to total exchangeable calcium and magnesium, and is determined as follows:

SAR, that according to Davies et al. (1982) gives an approximately determination of the Exchangeable Sodium Percentage (ESP) of the soil. Although, it has long been realised that

44 this is an arbitrary figure among soil scientists. Several classifications and threshold levels concerning the sodicity of a soil exists within the literature, but a threshold of 15 (ESP) is in general used as an indicator of sodic conditions, of which all sites within Gunung Kidul exceeded with a striking marginal (Tab.3). According to Landon (1991) a soil with the exchangeable Na > 1 me/100 g should be regarded as potentially sodic. This in additional confirms the already calculated ESP-values. Results from calculations showed that sites located in the regency of Sleman had an ESP ranging between approximately 6-18%, while the sites with its location in the Gunung Kidul regency have an ESP varying between approximately 24-42% (Tab.3). The SAR calculations indicate that the most sodic conditions occur in especially forested areas, such as for site 8-11. Tab.3. ESP- Value for the Different Sites. Site1 12.4% Site2 18.5% Site3 6.2% Site4 12.5% Site5 11.3% Site6 26.5% Site7 23.3% Site8 36.8% Site9 34.6% Site10 41.7% Site11 40.3% Site12 24.6% Site13 25.0% · The Cation Exchange Capacity (CEC) along the Merapi slope is relative low. The forested areas of Gunung Kidul shows considerable higher CEC, while the remaining areas within the regency have medium too high values. A certain pattern between the CEC values and the estimated ESP values above exist, together with an obvious relationship with the texture, indicating that clayey soils have significant higher CEC values. · Amount of organic matter and the percentage of total carbon within the soils are considerable higher in site 1 respective site 8, which also is covered with thick forest. · The acidity of the soils in the Sleman regency are in general slightly acid while the sites in Gunung Kidul varies from slightly acid to slightly alkaline. The more alkaline soils of Gunung Kidul are located in the forested areas, which also have the highest CEC values. · Ease of dispersion is an important factor influencing the erodibility of soils. The Dispersion Ratio Value in clayey soils is considerable lower compared with the more coarse-textured soils. Site 8, the forest in Playen have low infiltration capacity that has resulted in calcretes. In turn this give rise to the very low existing dispersion ratio occurring within the upper part of the profile. The Sleman sites have a less amount of exchangeable macro nutrients and therefore also lower CEC. The texture is coarse and increases with lower altitude. The dispersion ratio, foremost depending on the texture, is very high and the soils are slightly acid. The soil is although fertile with an increase in productivity. Sites in Gunung Kidul have clayey texture and therefore higher CEC and amount of macro nutrients (also depending on the lithology). Extremely sodic conditions occur and the dispersion ratio is also low The soils varies from slightly acid to slightly alkaline. Soil conditions within these sites are less favourable, and indicate severe degradation that also occurs today.

3. Land System Analysis

45 Following chapter is a compile of erosion hazard mapping, USLE-calculations, and the application of GIS. This includes the presentation of totally 4 maps. The first map presented in section 3.1 is an erosion hazard map, which is the result of field observations. Section 3.2 a soil loss map is the result of USLE-calculations based on field data. The land capability map in section 3.3, and the recommended land use map in section 3.4 was created with the help of GIS applications. Maps and other theoretical information together with data collected during fieldwork were combined in order to give a more accurate interpretation. 3.1 Erosion Hazard Assessment During the fieldwork phase mapping and classification of erosion hazards were made within each land mapping unit. According to the field observations the steep forest covered cone of Merapi is classified as an area with severe erosion hazard with many slides occurring (Fig.29). Human impact is not so significant in this matter and the hazard is depending on the steep topography combined with a high amount and intensity of rainfall that contributes to slides in the fine- textured soil. However, the natural thick forest layer offsets most of the erosion. The remaining sites located along the long volcanic slope had none to only slight erosion hazard all the way down to the permanently inundated foot plain area. The erosivity along the slope is high, although suitable soil conditions, mentioned in Factors Influencing Erosion on p.14, give rise to a high erodibility. Areas with moderate to high erosion hazard vulnerability dominate the foot plain of Merapi and the northwestern part of the Gunung Kidul regency, including site 6. This LMU is dominated by a steep hilly topography, but does not affect the sampling site showing no visible sign of erosion. This site, chosen for a more linear soil profile description, is positioned in the foot plain of the volcano and therefore have deposits of material transported from above. A plainer LMU, mostly cultivated with wet paddy rice, is located in the regency of Gunung Kidul further down. This LMU is classified as a non-to-slight erosion hazard area. Even though, the precipitation is relative low in the area were site 7 is positioned and some dry cracks in the clayey soil earlier mentioned can be found in the adjacent dryland of the investigated rice field. In the nearness of the Opak river is site 8, included in a LMU considered as an area with extremely erosion hazard. This forested sampling site is relative protected from erosion due to the dense vegetation that offsets the effects, while evidence of gullies and small slides occurs especially in areas more close to the river. Located on the forest covered Wonosari plateau with a rather hilly topography together with a thin soil layer is site 9-12, which has various conditions concerning erosion. Site 9 & 10 cultivated with kayu putih is highly eroded, while other areas higher up on the plateau is considered as moderate. The change from teak to Kayu Putih increases runoff and splash erosion. The reason of that is the lack of canopy on the Kayu Putih tree that also will have other effects on the soil characteristics. Finally, the very south part of the study area is classified as extremely severe erosion hazard area, containing large hilly areas with lack of vegetation. Soil Loss The soil loss map (Fig.30) is a result of the universal soil loss equation, with calculations based on field data collected in the study area (app.2 p.67). Most of the sample sites within the study area indicates on a rather low amount of soil loss. Although some parts of the area in the upper slope of Mt. Merapi, utlilizated as dryland have higher loss of soil. The highly eroded LMU in the very south is also effected by severe soil loss due to the loss of vegetation and to the characteristics of the topography.

46 Fig.29. Erosion Hazard Map (Source: Field Mapping)

Fig30. Soil Loss Map of the Study Area. (Source: USLE-calculations based on field data).

47 Fig.31. Land Capability Map (Source: GIS-applications, see further in the GIS section on p.20) Fig.32 Map of Recommended Land Use (Source: GIS-applications, see further in the

GIS section on p20)

3.2 Land Capability Classification

48 The evaluated land capability, with focus on erosion risk, within the study area is showed in Fig.31. A matching method based on a total of eight maps over physical features split into different criteria’s has been used to accomplish this matter. The map indicates that areas with forest and wet paddy rice usually have low potential erosion hazard. An exception is some rice fields located in more steep areas at the border of the Sleman and Gunung Kidul regency. Most of the areas covered with dryland are of low potential erosion hazard, but dryland located in the rather steep areas within foremost the regency of Gunung Kidul, and also in the upper volcanic slope, although have high potential erosion hazard. 3.3 Recommended Land Use within the Study Area The final and most important purpose with this research is to indicate how balanced conditions, or matching between the physical features and utilization of land within the study area can be achieved. Therefore, a recommendation map for land use (Fig.32) was made in order to facilitate the presentation of this matter. These suggestions or recommendations are, in contrast to the land capability map, totally based on interpretations and mapping of land characteristics as well as analysis of soil samples and USLE-calculations. Local knowledge in land management and other socio-economic and cultural factors has also been taken under consideration. The recommendations are as follows: The cone, already covered with a dense natural conservation forest, seems to be the best alternative for protection of the soil against erosion. Due to flooding and sedimentation conservation practices can also be suitable in river zones within the whole study area. Further down on the upper slope a dryland area with high potential erosion hazard is found. This area is, according to the USLE-calculations partly liable to severe soil losses. Therefore, a conversion to forest, with the function as a water holding zone, is recommended to be the best alternative. According to Jansson (1982) agricultural practices reducing the vegetation cover increases erosion. A large area, for the time being cultivated with wet paddy rice, along the middle to lower Merapi slope could therefore be replaced with forest in order to reduce the rapid drainage of water occurring. The plain wetland areas at the end of the slope could although remain cultivated with paddy rice, or other crops suitable for wetland cultivation. The lower slope of Merapi down to the foot plain mostly consisting of wet paddy rice fields could instead be converted to dryland areas if the zone above has a function as water holding forest. The very north part of the regency of Gunung Kidul is in general cultivated with high potential erosion hazardous dryland. A land use change to forest with the function as a productive protection area is an alternative. This would increase the protection against the relative high erosion by a higher amount of organic matter and other soil characteristics that improves the soil structure. A reduce of chemicals, such as pesticides and herbicides will also follow by that. According to the land capability map, the majority of dryland that exists within Gunung Kidul is classified as low potential hazardous. If parts of these areas are reforested or afforestated an increase of the less favourable soil conditions will be improved of same reasons mentioned earlier. Finally, the large eroded coastal area in the very south of the regency, and also the similar classified regions in the nearness of the river Opak, could be converted to nature reserve because of its very disadvantageous cultivation conditions. These areas are according to the land capability map of low potential hazard, but the very thin soil depth and other less favourable soil characteristics have not fully been taken under consideration during the creation of the map.

4. Local Knowledge in Land Management

49 This section of the results is based on interviews made during the fieldwork period with farmers and engineers in conservation practices from the study area.

The attitude among farmers concerning management of the soil, crops and other vegetation is very traditional. The land is usually inherited for many generations and not many changes in land use or management of the land has been done through the years. According to the interviews most of the people are afraid to try another kind of cultivation to improve their economical situation. They usually have the same kind of cultivation all the life. All of the farmers have done some kind of conservation practice to protect their land against erosion. Mechanical methods dominated by terracing with local stones are frequently used within the whole study area. People in general have stone terraces made of pyroclastics in areas near the volcano, and limestone from the bedrock in the other areas. The local people in Sleman also use sand, pebbles, gravel and other coarse material, that comes down the volcanic slope during rainfall, as construction material. Since many of the terraces are old and therefore less effective because of weathering, it seems like the maintenance of already existing terraces is the most common way to protect the land against erosion. This occurs especially in the regency of Gunung Kidul were limestone terraces are destroyed, due to rainfalls, which dissolve the calcic material. Research done in Gunung Kidul (Oral Setyarso 1998) although shows that terraces on some steep slopes having a shallow soil depth may be deeper than the subsurface flow. As a result water runs out of the riser face and on to the terrace below, with the result that 90% of the rainfall becomes runoff causing serious erosion. Cultivations located along the slope of Mt. Merapi also use waterways as a further alternative to control the land against intensive rainfall. Contouring by ploughing, planting and cultivation is also practised among most of the farmers to protect their land against soil loss in slope areas. Contour bounding and earth banks, is other methods frequently used as a barrier to runoff. Crops and vegetation management practised in the area is strongly depending on the land utilisation type. Multiple cropping by intercropping is generally used in dryland areas, which is considered to be a favourable alternative recommended by the Department of Forestry (Oral Sutamto & Sukasno 1998). Strip cropping and multiple cropping by sequential cropping, is more common among the interviewed people in the regency of Sleman, and can be related to land utilisation types like salak cultivation. Strip cropping is a relative new method and not yet so very common conservation measurement on Java, but this method is considered to be a cheap and suitable management method with long protection and good effects, especially for runoff control, and as animal food (Oral Suparto, 1998). Another suitable alternative, as a cheap and easy conservation method against erosion and sedimentation, is alley cropping. Alley cropping is, according to Mr. Suharsono at the Department of Forestry, Yogyakarta especially useful on bench terraces in dryland cultivation's, and also contributes to an increase of mulch and organic content. It is in addition to that useful as animal food and firewood. Regular weeding and applications of fertiliser's etc. is carried out. Row crop cultivation is according to Morgan (1986) usually give rise to more erosion problems due to the high percentage of bare ground, particularly in the early stages of crop growth. However, row crops within the study area are combined with high density planting of other vegetation to prevent erosion. This management (agroforestry) is very common among farmers and also seems to have advantageous effects. Combination with forest management or other rotational cropping is also done all over the area as a way of controlling erosion.

50 Conventional tillage such as ploughing together with the adding of animal dung is most common in soil management. Soil stabilisers also occur in some cases. Numerous studies concerning the effects on convention tillage on soils have according to Morgan been done. The results showed that conventional tillage sometimes causes problems, especially on structureless soils with a high sodium content but no explanation about this statement is given.

VI. DISCUSSION

51 This thesis concerns a specific purposed land evaluation of which the specific purposes in this case comprise the interpretation and comparison between two areas with different physiographic features. The overarching aim that concerns the relationship between the physical features and utilization of land will be discussed, as well as the objectives that were put up to answer that aim. The first objective achieved was the elaboration of land utilization types within the study area. This were carried out by semi-detailed mapping based on field observations and a land use map from 1994/95, and due to relative homogenous utilization types this were done without any specific problems. Next objective concerned the terrain stability, which included erosion hazard mapping as well as slope stability. Since the study area comprised an approximately 60*20 km large area and the Land Mapping Units, classified by RePPProT (1989), were in scale 1:250.000, the mapping of the erosion hazards therefore had to be generalised for each unit even though some minor variation occurred. Erosion hazards in Sleman are rare and visible soil conditions are favourable. This because of the volcanic influence within this area that creates advantageous growing conditions due to the minerogen deposits increases the erodibility of the soil that offset factors like high amount and intensity of rainfall as well as a sometimes rather steep topography exists. The very high rainfall that usually occurs in volcanic areas as a result of the relief in turn promote infiltration and reduce the shear strength and by this also that minerals can be weathered and therefore become more available for the vegetation. Conditions in Gunung Kidul, concerning erosion hazards, is a contrast to the Sleman area. Cultivation land within the karstic limestone-rich areas indicate disadvantageous growing conditions and also severe to extremely severe erosion in a dominant part of the regency. Lime- rich areas are more sensitive to chemical weathering that dissolves the calcium carbonate, and therefore also cause leaching due to the high amount and intensive rainfall that occurs. The evapotranspiration within the area also exceeds the precipitation, causing the calcium and other salts to accumulate, especially at the surface. This will contribute to the severe erosion rates occurring as a result of runoff. This is according to Reading, Thompson & Millington (1995) a common problem recognised in especially humid tropical areas The slope stability was in field indicated with measurements of shear strength within the strategy chosen soil profiles. These tests gave relative accurate indications of the stability, with exemption for some areas were the soil layers were to thin and therefore not possible to carry out. This type of testing (field shear box) is according to Selby (1993) particularly useful in studies of soil erosion, and for comparing the strength of soils under different kind of vegetation. The results of the test shows that the shear strength is especially low in the steep and more coarse-textured volcanic slope with dryland as land utilisation type. With exception for the rainfall and topography as depending factors, a vegetation cover with low organic content, as in this case, can sometimes increase infiltration and interflow along root channels. Calculations with USLE, based on field data, were performed as a further complement, or indication to slope stability, showing the potential soil loss within the area. The reliability of USLE has been discussed in numerous cases before because of its restriction to USA contributing to limitations in application within other parts of the world. However, this method is commonly used for long-term prognosis and is also specific for rill and sheet erosion that occurs in a great extent in a tropical environment. Estimations with USLE point out same drylands earlier mentioned concerning shear strength to be highly subjected for soil loss. In reality some soil loss within this areas has been noted, but at the time being agroforestry with high density planting of many various species exist. This is so far promoting soil loss to occur in larger quantities.

52 Unfortunately this large study area is represented by to few sampling sites as reference for the whole area. The variation in both land utilization and topography varies a lot on a relative low scale which results in deviating values calculated on the whole region. This especially with thought of the more heterogeneous conditions existing in the regency of Gunung Kidul. Another objective was to indicate the land capability. In order to achieve that, visible and further analysed soil characteristic together with other land characteristics were taken under consideration. The earlier described erosion hazard mapping as well as interviews with local farmers were also used for this matter. The interviews concerned land conditions, land management, socio-economic and cultural conditions. Since the productivity of land, according to the majority of all interviewed farmers in the regency of Sleman is increasing the capability of land is not exceed and indication of soil loss estimated in a long-term was, as told earlier, only noted for some parts along the slope. According to Sudibyakto & Abasi (1996) the long-term prognosis for this area can also be an improvement of the micro-climate as a result of the fresh and dense vegetation growth. All other visible characteristics of the soil indicates on favourable conditions, but further laboratory analysis showed that the level of exchangeable macro nutrients, such as potassium, magnesium and sodium were low. This could be the cause of leaching processes that is common in acid-coarse textured soils like this. A possible overuse of fertilisers and other chemicals, which is frequently used along the slope, can also contribute to a reverse effect promoting a decrease in soil fertility by the leaching of important nutrients. This has been confirmed in several cases around the world. The north to Northwest part of the regency of Gunung Kidul, positioned in the foot plain area have soil layers that reaches more than 1,5 meter. The colourful orange-reddish profiles have good growing conditions, which also were confirmed by the laboratory analysis. The colour of the horizon indicate on a high amount of sesquioxides that may have dissolved away the quartz which also contribute to the held of exchangeable cations. Input of soil from the slope above, together with a finer texture is reducing the possibility of leaching. Therefore, the land capability within this part of the regency is not exceeded. Further south, including the limestone-rich areas of Gunung Kidul the productivity of the soil is, according to the local farmers, decreasing since a few years back in time. The amount of macro nutrients although shows normal conditions according to several classifications of soils in similar environments. However, extremely high values of exchangeable sodium were found within these sites. Since sodium soils according to Landon (1993) are noticeable in its deleterious effects on soil structure a connection between the low infiltration rate that already exists can be an important factor influencing the already exceeded land capability. One example is the highly eroded area in the nearness of river Oyo that embraces the most sodic conditions. They are both positioned in moderate slopes above a flood plain and flooding is also common during the wet season. According to Ellis & Mellor (1996) this is typical condition for sodic soils in an environment like this. Estimation of the land capability was the following objective to this. The method chosen for this was theoretical with exemption for the included erosion hazard map done during fieldwork. Based on eight important maps over physical features this was carried out with the help of GIS. This resulted in a map indicating high potential erosion hazard areas as well as low potential areas within the study area. The results received with this method indicated on less high potential areas than expected. With the fulfilment of the former objective in mind I could clearly see the importance of the analysed soil characteristics as well as the farmers indications on the productivity. No consideration concerning the very sodic soil conditions was taken by the application of this method, which is of great importance and relevance for the estimation of land capability within this area. The farmers living within areas, classified as low potential for erosion, has although noted a decrease 53 in productivity, which not have been considered with the application of GIS. Therefore, a combination between the GIS application and the field data, including interviews and soil sampling, is necessary to give a more complex presentation of the actual potential areas. GIS is a very useful tool in the creating of maps, and the applying of GIS in land evaluation analysis will facilitate the linking between all depending factors that usually exists. However, the combination of physical maps and demographic maps, such as population density is seldom used in the creation of for example a land capability map. This could be used in a bigger extent since demographic data concerning this matter in most of the cases is relative available. One of the negative sides is although that the demographic data usually is in tabular form, which like in my case can cause problems due to limitation in time. Another suggestion could be to apply the TP-formula (app.2 p.67), which is a common formula used in Indonesian socio-economic analysis for calculations of the carrying capacity of land. A map of TP, the population pressure could result in an accurate land capability map when overlaid with other maps. Since the interviews are of great importance for further land use planning as well as for conservation practises a try to understand how the physical features of land affects the people as well as people's respond to the land system were done. By using the information concerning land management and socio-economic conditions, together with cultural aspects, in combination with indications of land capability conditions a further objective could be fulfilled. The farmer's interest to obtain the maximal output from the land has an influence on the land capability. In areas were the capability of land is exceeded, the introduction of new conservation practices or a conversion to another kind of land utilization type should be carried out. Many researches on especially Java have according to Kusumandari & Mitchell (1997) suggested agroforestry as a favourable alternative for prevention of particularly the soil loss. Erosion although occur within these already existing agroforestry areas of Gunung Kidul but an improvement of this utilization type by planting trees of less height will, as earlier mentioned in the theoretical background on p.16 give a further protection from runoff. However, the attitude among the majority of farmers concerning introduction of new crops or vegetation, as a way to increase the productivity of land, is traditional. They main problem is that these farmers are insecure if they will be able to make a profit at the market if they have other species and therefore prefer to only improve or maintenance the management of land. The requirements of commercial crops and other traditional medicine plants also have a strong influence within this area. This confirms an already recognised problem all over the world. Farmers in poor rural areas are according to Morgan only willing to adopt soil conservation practices if they perceive an immediate economic benefit, which sometimes is difficult to estimate. That adoption of new conservation methods is although only possible if they have necessary labour, capital and technological inputs. Morgan further points out another conservation problem by referring to a situation that occurred in Java in the 1980s. Six government organisations with different responsibilities worked alongside in a watershed project. The little co-ordination of activities as well as the competition to work on different aspects between these organisations became confusing for the farmers and other people involved. To avoid a situation like this project and other research on both high and lower level must be better organised. To achieve that further understanding and projects with people of different disciplines is necessary. Successful government projects within the regency of Gunung Kidul although exists. The idea to have community forests prioress within the poorer areas have a positive influence on the land as well as a safety function with benefits for the farmers that are depending on an extra income. The achievement of the research within the area might also lead to the adoption of sometimes more suitable conservation measures than the usual ones.

54 Sometimes an improvement of the management of land is not enough. As told earlier in the section for management on p. 48, evidence of load caused by terraces in some parts of Gunung Kidul have been noted and therefore a conversion of the land to another kind of utilization is a further alternative. Suggestions concerning land use was in the form of a recommendation map for land use presented earlier in the results. The aim with this map is to combine my own field data together with some local knowledge about the study area, and by that create a more realistic situation. Most of the maps I have studied concerning land use are mainly based on two or three maps over physical features such as slope, rainfall and soil type. During my period of fieldwork I realised that the matching between reality and theoretical seem to differ a lot in some cases. I therefore believe that the importance of applying more actual field observations together with field mapping is necessary in order to give a more accurate illustration, meaning that more priority should be given to fieldwork within research concerning land evaluation systems. The discussion above concern problems related to the degradation of land. Clear is however that external factor especially including volcanic eruptions have great impact within this environment. At the time of the compile of this thesis (August 1998) disquieting news concerning another severe eruption from Mt. Merapi, affecting parts of the study area has been reported. Lava flows and the throw out of gas has already occurred, and so far 3,000 people from the volcano's surrounding has been evacuated. The severity and damage caused by the eruption is difficult to estimate but it will for sure have an impact on the cultivated land by the burning of vegetation and the burial of land. I would therefore like to finish this discussion by saying that land use planning within this unstable area is difficult to apply concerning the karstic areas that includes special features and sodic soils as well as along the volcanic slope having a frequent and sometimes unexpected volcanic activity.

VII. CONCLUDING REMARKS The physical features within the study area is distinct and the overarching aim within this study is to indicate how these physiographic features affects the people and people's respond to the characteristics of the land system. Several objectives have therefore been put up as a way to answer this key question. Conclusions regarding these objectives will be presented below I. The elaboration of land utilization types within the study area was classified into three main groups of cultivation including several kinds of species. The utilization of land within the regency of Sleman is homogenous with conservation forest at the cone, dryland along the upper slope, and wet paddy rice field along the remaining part of the volcanic slope also covering big parts of the plain area. A more heterogeneous distribution of land utilization occurs in the regency of Gunung Kidul. Wet paddy rice

55 fields cover the low altitude areas in the north to Northwest of the regency. Forests are found on the karstic Wonosari Plateau as well as in the adjoining areas, mostly covering the hilly parts. Remaining areas consists of dryland. II. No visible evidence of erosion exists along the Merapi slope, with exception for the slopes located on the very steep cone were several landslides occurs. Potential soil loss is although indicated by USLE-calculations for some coarse-textured drylands along the upper slope, and the shear strength is also very low. According to the soil analysis some nutrition losses of for example potassium occur, which can be the results of leaching processes. The karstic areas of Gunung Kidul are exposed to soil erosion in different degree. Sites in the nearness of Opak River have evidence of gullies, slides, weathering, compaction, calcretes, stoniness, drought and a very thin soil layer. Occasionally flooding also happens in some cases. A huge part of the region in the very south of the regency is classified as extremely severe erosion hazard area with steep hills almost bare from soil and vegetation. Besides this the whole area suffers from severe sodic conditions. The human impact has the most significant influence on soil erosion including land utilization as well as the management of land. III. The land capability within the study area based on observed erosion hazards, visible soil characteristics and other land characteristics, together with the interviews made with local farmers and indicates on an exceeded land capability in all sites in Gunung Kidul. Local farmers within the karstic areas on the whole consider their land to be less fertile even with a decrease in productivity. Therefore, this regency is considered to have the most disadvantageous conditions concerning cultivation within the special district. This with exception for the volcanic influenced region in north and the Wanagama forest research area. IV. Estimation of the land capability with the help of GIS included interpretation of physiographic maps. The application of GIS partly confirm the above mentioned indications of land capability but is not taking the less favourable analysed soil characteristics into consideration. Furthermore, no regards concerning the statements of a decrease in productivity of the land made by the local farmers is done. The land capability map shows high potential erosion hazards for the drylands in the upper slope as well as some wet paddy rice fields located in steeper slopes in the Northwest of the regency of Gunung Kidul. Remaining areas is classified as low potential hazard areas. V. Clear is that the very different physical conditions that exists within the study area also is deciding the distribution of the economical profits for the farmers. Some socio-economic & cultural factors influencing the degradation of land within the study area are mainly considered as a result of the farmers intention to obtain the maximal output from the land without considering the land capability. The Government also owns big parts of the forested areas. This can with thought of the earlier conclusion have a positive influence on the land as well as a safety function with benefits for the farmers that are depending on an extra income. The achievement of the research within the area might also lead to the adoption of sometimes more suitable conservation measures than the usual ones.

The very different physical features within the study area affects the people in several ways and have a considerable influence on the erodibility of the soil and therefore also on the productivity. Generally speaking, sites located in the volcanic slope have advantageous cultivation conditions while sites within the limestone-rich areas have less favourable conditions. People's respond to

56 these land conditions is still to keep the land under intensive use because of economical reasons. This has resulted in an exceeded land capability in big parts of the regency of Gunung Kidul.

IX. REFERENCES

Literature · Armson, K (1979) Forests Soils, Properties and Processes. University of Toronto Press. Toronto 390 p. · Boodt, M & Gabriels, D (1980) Assessment of Erosion. John Wiley & Sons. Great Britain. p. 563 · BPS, Kantor Statistik (1996) Daerah Istimewa Yogyakarta Dalam Angka 1996. D.I.Yogyakarta · BPS, Kantor Statistik (1996) Kabupaten Gunung Kidul Dalam Angka 1996. D.I.Yogyakarta · BPS, Kantor Statistik (1996) Kabupaten Sleman Dalam Angka 1996. D.I.Yogyakarta · BPS, Kantor Statistik (1996) Jawa Tengah Dalam Angka 1996. D.I.Yogyakarta

57 · Data PertanianWilayah Propinsi D.I.Y (1996).Departemen Pertanian, Kantor Wilayah D.I.Yogyakarta. · Davies, B, Eagle, D, Finney, B (1982) Soil Management. Page Bros (Norwich) LTD., Norwich. P. 287 · Department of Forestry, Yogyakarta Daerah Aliran Sungai Opak-Rencana Teknik Lapangan Rehabilitasi Lahan dan Konservasi Tanah Sub Daerah Aliran Sungai Oyo 1993) · Diercke Weltatlas. (1992) WestermannSchulbuchverlag GmbH, Braunschweig. 275 p. · Ellis, S & Mellor, A (1995) Soils and Environment Routledge. Great Britain. 364 p. · Indonesien, Länder i fickformat. (1994) Utrikespolitiska Institutet. Stockholm. p. 40. · Jansson, M (1982) Land Erosion by Water in Different Climates. UNGI Rapport Nr 57, Uppsala University, Department of Physical Geography. Borgströms tryckeri AB. Motala. 151 p. · Kusumandari, A & Mitchell, B (1997) Soil Erosion and Sediment Yield in Forest and Agroforestry Areas in , Indonesia. Journal of Soil and Water Conservation. Vol. 52 No 5. p. 376-380 · Lamporan - Pengadaan dan Penggambaran Paper Print Citra Satelit dan Peta-peta Penafsirannya Untuk Penyebaran Potensi Kayu Rakyat Propinsi D.I.Yogyakarta- Dalam Rangka Perencanaan Pengelolaan Hutan Rakyat. Fakultas Kehutanan & Kanwil Kehutanan D.I.Y. (1996) 22 p. · Morgan, R (1995) Soil Erosion & Conservation. Longman Malaysia. 198 p. · Muhamud, N. (1996) Directions of Soil Conservation as a way of Conserving the Capability of the Environment in Sedayu Sub-District-Bantul District, Yogyakarta. Gadjah Mada University. Yogyakarta. 204 p. · Reading. A, Thompson. R, Millington. A (1995) Humid Tropical Environments. Blackwell. Great Britain. 429 p. · RePPProT (1989) Review of Phase 1. Results. Java and Bali Vol.2 Annexes 1-5. Land Resources Department ODNRI, Foreign & Commonwealth Office UK, Government of the Transmigration Directorate, General of Settlement Preparation. United Kingdom. · Ross. M (1984) Forestry in Land Use Planning -policy for Indonesia. University of Oxford. Great Britain. 266 p. · Rowell, D (1994) Soil Science, Methods and Applications. 1994. Longman. Singapore. 350 p.

· Selby, M (1993) Hillslope Materials and Processes. Oxford University Press. Great Britain. p. 451 · Soil Map of the World. Vol.1Legend (1974) FAO-Unesco. Paris. p.59 · Sudibyakto & Abasi, S (1996) The Eruption of Merapi Volcano, November 22, 1994, The Geographical Review. The Indonesian Journal of Geography Vol.28, No.72. Faculty of Geography, Gadjah Mada University, Yogyakarta. pp.1-10 · Suharsono et al (1996) Bahan Seminar. Departemen Kehutanan D.I.Yogyakarta. · Sutikno (1996) Geomorphology of Yogyakarta Area and its Surroundings proposed as a geomorphological Field Laboratory. The Indonesian Journal of Geography Vol.28, No.71. Faculty of Geography, Gadjah Mada University, Yogyakarta. pp.1-10 · Swedforest International AB & PT. Wahanabhakti Persadajaya (1995) Final Report. Regional Management Plan. Part 1, Fundamentals of Regional Planning, East Kalimantan Province. Departemen Kehutanan, Direktorat Jenderal Pengusahaan Hutan. Jakarta. 109 p. · Trudgill, S (1983) Weathering and Erosion, Sources and Methods in Geography. Butterworths. London 192 p. 58 · User's Manual, ILWIS 1.4. (1993) ITC-International Institute for Aerospace Survey and Earth Science Netherlands. · Whitten, T, Soeriaatmadja, R, Afiff (1996) The Ecology of Java and Bali. Periplus Editions. Singapore. 969 p. · World Bank, (1994) Indonesia-Environment and Development. The International Bank for Reconstruction and Development. Washington D.C. 294 p. · Woro, S (1990) Toposequence of Soils on the South Slope of the Merapi Volcano to Baron Coast, Yogyakarta. The Indonesian Journal of Geography Vol.20, No.59. Faculty of Geography, Gadjah Mada University, Yogyakarta. pp.25-39 · Yanda (1995) Temporal and Spatial Variation of Soil Degradation in Mwisanga Catchment, Kondoa, Tanzania. Stockholms Universitet. Edsbruk Akademitryck. Stockholm.

Data Bases

CD-ROM · Encarta 98, Encyclopedia. 1998. Microsoft Corporation. USA.

Internet · Martaamidjaja.(1996) Group-based Extension Programmes for Natural Resource Conservation in Java. Ministry of Agriculture, Indonesia. http://www.fao.org/WAICENT/FAOINFO/SUSTDEV/EXdirect/EXan0012.htm · Marcoux (1996) http://www.cgiar.org/cifor/publications/occpaper/occpaper9.html · ID/ID: Indonesia (1993). ID/ID: Indonesia. http://www.adfa.oz.au/CS/flg/wf93/id.html. · Indonesia-a case study (1992), http://www.umanitoba.ca/indonesian/indo-in-b.html · Indonesia-a country study (1992) Indonesia - a country study. http://lcweb.2.loc.gov/c...dy: @field(DOCID+id0043). · Sunsite (1996) http://sunsite.ui.ac.id/about_indonesia/physio.html. · Surabaya International School (1996) Indonesia, rich in culture. http://www.rad.net.id/users/personal/s/siscoord/indo.html · Travel-Indonesia (1996) Introducing Yogyakarta. http://www. travel- indonesia.com/yogya/ygy_home.htm

Maps · Jawa Sheet 1407 Parangtritis.Land Systems/Land Suitability. Land Systems with Land Suitability & Environmental Hazards. Scale 1:250.000. Serie RePPProT (1989) · Jawa Sheet 1408 Yogyakarta.Land Systems/Land Suitability. Land Systems with Land Suitability & Environmental Hazards. Scale 1:250.000. Serie RePPProT (1989) · Penggunaan tanah, Propinsi D.I.Y, (1994/95), scale 1:100 000 · Peta Airtanah D.I.Y. scale 1:250.000 Laboratorium Kartografi, Fakultas Geografi, Universitas Gadjah Mada. Yogyakarta). · Peta Dati II, Jenis Tanah, Kabupaten GK, scale 1:100.000 (1988/89). · Peta Fisiografi. Propinsi D.I.Y., scale1:250.000, Mitojat dkk (1987). · Peta Geomorphology.D.I.Y.. Scale 1:250.000 Laboratorium Kartografi, Fakulats Geografi, Universitas Gadjah Mada (1990). · Peta Kemampuan Tanah Prop. D.I.Y, scale1:100.000, Kanwil Badan Pertanahan Nasional. Prop. D.I.Yogyakarta.(1994/95)

59 · Peta Paduserasi Rencana Tata Ruang Propinsi dan Tata guna Hutan D.I.Y (TGHK). Badan Perencanaan Pembangunan Daerah (Bappeda) Prop. D.I.Yogyakarta. (1992). · Peta II.3.Sebaran janis-janis tanah di prov. D.I.Y, scale 1:250.000 (1992). · Pola Curah hujan prop. D.I.Y Scale: 1:100.000. Dinas Pertanian dan Dinas Pengairan Kabupaten Dati II se Prop. D.I.Y (1982/92))

Oral Sources · Setyarso, A. (1998) Dr. Ir. Forestry MSc. Faculty of Forestry, Gadjah Madah University, Yogyakarta · Sukasno, Ir. at the Rehabilitation and Land Conservation Bureau (RLKT), Department of Forestry, Yogyakarta · Suharsono, Ir. at the Rehabilitation and Land Conservation Bureau (RLKT), Department of Forestry, Yogyakarta · Suparto, Ir. at the Rehabilitation and Land Conservation Bureau (RLKT), Department of Forestry, Yogyakarta · Sutamto, Ir. at the Rehabilitation and Land Conservation Bureau (RLKT), Department of Forestry, Yogyakarta

Visited Faculties & Offices · Department of Soil Science, Faculty of Agriculture, Gadjah Mada University, Yogyakarta · Faculty of Geography, Gadjah Mada University, Yogyakarta · Faculty of Forestry, Gadjah Mada University, Yogyakarta · Faculty of Social Science, Gadjah Mada University, Yogyakarta · Office for Province Development Planning (BAPPEDA), Yogyakarta · Offices for Social and Politics in Gunung Kidul, Yogyakarta · Offices for Social and Politics in Sleman, Yogyakarta · Offices for Social and Politics in Yogyakarta, Yogyakarta · Offices for the Gunung Kidul Regency Development Planning (BAPPEDA), Yogyakarta · Offices for the Sleman Regency Development Planning (BAPPEDA), Yogyakarta · Province office (Kantor Wilayah), Department of Agriculture, Yogyakarta · Province office (Kantor Wilayah), Department of Forestry in Yogyakarta · Rehabilitation and Land Conservation Bureau (RLKT), Department of Forestry, Yogyakarta · Statistic Bureau (BPS), Yogyakarta · The Forestry office (Dinas Kehutanan), Department of Forestry, Yogyakarta

60 IX. APPENDIX 1. Geographical Description 1.1 Indonesia There are five large islands and four of them are collectively known as the Greater Sunda islands; Jawa (Java) is the main island with about 115 million inhabitants (Microsoft Corporation 1998). This is the most fertile and rich island, in terms of its contribution to national sectoral gross domestic product (ID/ID: Indonesia 1993). Sumatera (Sumatra) with about 40 million inhabitants ranks second in economic terms with large rubber plantations, Sulawesi (Celebes) with about 14 million inhabitants and Kalimantan, the Indonesian part of Borneo is sparsely populated with about 14 respective 10 million inhabitants. The fifth large island is Irian Jaya, the eastern most part of New Guinea, shared with the independent state of Papua New Guinea. Extending eastwards from Java are the Lesser Sunda Islands, including Bali, Flores and Timor. Another island chain is the Moluccan Island, located between Sulawesi and Irian Jaya. Indonesia is also home to the worlds largest Muslim population (87% of the population) (Surabaya International School 1996), but wide waters and high mountains have helped perpetuate cultural distinctions and differences, resulting in 300 discrete ethnic clusters, over 250 individual languages, and just about every religion practised on earth (Utrikespolitiska Institutet 1994 pp.7-10). Centrifugal political forces have been powerful and, on more than one occasion, nearly pulled the country apart. One of the most important political episodes ever happen within the nation is at the moment, spring 1998, taking place with former President Suharto's suddenly retirement after 32 years of power. Many volcanoes in Indonesia are still active, and earthquakes also occur. Volcanic flows, that periodically have occurred over many centuries have deposited fertile volcanic soils on the lowlands, particularly on Java, which makes ideal conditions for cultivation. Some volcanic mountains, included in the volcanic chain stretching from Timor up to Sumatra, exceed heights of more than 3568 m. The highest mountain in Indonesia (5030 m) is located in Puncak Jaya, in the Sudirman Range of Irian Jaya (Diercke Weltatlas 1992). The weather between the monsoons is moderate. The northern parts of Indonesia have only slight differences in precipitation during the wet and dry seasons occurring in November to March respective June to October. Humidity is generally high averaging about 80%. The daily temperature ranges about 20-320C and varies little from winter to summer. Rainfall in the lowlands averages about 1780 to 3175 mm annually and about 6100 mm in the mountain regions" (Microsoft Corporation 1998). Tropical rain forest vegetation prevails in the northern lowlands, mangrove trees and nipa palm dominate the forests of the southern lowlands. The hill forests consists of oak, chestnut, and mountain plants. Forestland covers about 60-70% of the total land area and the majority of the forest is state owned. Cultivation's covers about 12 % of the land area and about 55% of the country's approximately 70,4 million workers are engaged in agriculture, either as owners of small farms or as labourers on estates. The small farms, which produce most of the subsistence crops, also contribute substantial proportions of the nation's rubber crop, tobacco crop, and total export production. Plantation estates produce rubber, tobacco, sugar, palm oil, coffee, tea, and cacao, mostly for export. Rice is the major staple food of the country, other important crop are Cassava, maize, sweet potatoes, coconuts, sugarcane, soybeans, peanuts, tea, tobacco and coffee (BPS, Kantor Statistik Jawa Tengah. 1996).

61 1.2 Java The Indo-Australian plate dips beneath the Sunda Plate along the Java trench, causing earthquakes and a landscape dominated by volcanoes (Witten et al 1996 p.87). The island is also the most volcanically active island in the world, with 35 active craters (Indonesia-a country study 1992). The southern part, and also the northern parts of the island chain consists of sedimentary rocks that provides the country with oil and natural gas resources (Microsoft Corporation 1998). The island can be divided into four physiographic regions: The northern alluvial plains, the northern Foothills and Plains (karstic), The central Volcanic Mountains, and the southern Dissected Plateaux and Plains (karstic) (Witten et al. 1996, p.105). Yearly climatic variations are governed by the oscillations of air masses within the ITC zone (Whitten et al. 1996, p. 119). Monsoons are usually blowing in from the south and east in June through September and from the Northwest in December through March (Indonesia-a country study 1992). Dry season in Java normally last from March to August. The wet season usually last from September through March with the heaviest rainfall usually starting from November through February (travel-Indonesia 1996). The climatic conditions in Java varies on a relative local scale, depending on the islands topography and prevailing wind patterns (Indonesia-a case study 1992), but over 90 % of Java and Bali receives at least 1,500 mm in annual precipitation. There is also a big variety in temperature and humidity. The temperature decreases with altitude by about 0,6 0C every 100 m and usually ranges between 200C and 300C, and the humidity, often disturbed in those areas affected by trade or monsoon winds, varies between 60% to 90% on the island. Temperature and humidity vary more between night and day than between months or years. The total number of plant species on Java, including weeds and cultivated species, is over 6500, with about 4500 native species (Whitten et al 1996 pp.119-125). The present remaining forested area on Java although indicate on a more than 90 percent decrease in forest cover since around 200-400 AD (Whitten et al 1996 p.328), as a consequence of human impact, volcanic eruptions, earthquakes, and strong winds (Tab.6.).

Tab.6. Original and Present Forest Cover in Java. (Simplified after Witten et al 1996) Present Original Area Present Area Vegetation Type Remaining Area (km2) (km2) (%) Evergreen Rain Forest 26.949 1.902 7.00 Semi-evergreen Rain Forest 22.235 1.764 7.90 Moist Deciduous Forest 61.292 1.436 2.30 Dry Deciduous Forest 4.902 167 3.40 ASeasonal Montane Forest 3.065 907 29.6 Seasonal Montane Forest 13.704 4.227 30.8

Java is only forest covered with approximately 9% compared with 60-70% for the whole nation. Most of it is converted to national parks and recreation areas (Ross 1984 p.10). Wetlands mostly cultivated with paddy rice are the dominating land utilisation type, covering 23% of the land area. Tree crops (and estates) as well as upland farming is also very common for the island (World Bank 1994). Tree crops together with estate crops covers approximately 19% of the totally cultivated land, upland farming about 18% (Whitten et al 1996 pp.9-11).

3. Daerah Istimewa Yogyakarta (Special Province) 3.1. Physiographic Conditions

62 Geomorphology The very specific geomorphic features within the regencies are mostly depending on its location to the volcano or the coastal area. The regency of Sleman is located in the volcanic cone, slope and foot of Mt. Merapi: Yogyakarta in the volcanic footplain of Mt. Merapi; Bantul in the fluvio volcanic plain and coastal area; Gunung Kidul in a karstic and coastal area; Kulon Progo in a hilly and mountainous area, and coastal alluvial plain (Sutikno 1996, p.2). As well as for other places along especially the West Coast of Java Island, plate tectonic movement between Eurasian and Indian-Australian plate influences Special Province Yogyakarta. Volcanic deposits from the still active strato volcano Mt. Merapi covering big parts of especially the regency of Sleman and Bantul. Fold and fault therefore occurs in the regency of Gunung Kidul respective Kulon Progo (Sutikno 1996, p.3).

Topography The topography within the special district varies from flat to mountainous with about 65% of the total area having an elevation between 100-500 m.a.s.l. (Tab.7a). The altitude in the northern part, located in the volcanic slope area of Mt. Merapi varies from 80-2911 m.a.s.l. (BPS, Kantor Statistik D.I.Y. 1996). In the southern part of D.I. Yogyakarta, including the regency of Bantul and Gunung Kidul, the altitude is less with 0-500 m.a.s.l. Some parts of the large karstic Wonosari plateau, located in the central part of Gunung Kidul, although reach an altitude of 900 m.a.s.l (see further details in the result section on p.25). Finally, the western part, Kulon Progo, has an altitude between 0-786 m.a.s.l. (Sutikno 1996, p.3).

Climate

63 The climate within the Special Province is, as well as for whole Java, is varying on a relative local scale. The average temperature varies between 23,6-31,7 0C, with an average yearly humidity between approximately 75-88 % (BPS Kantor Statistik D.I.Y. 1996). The precipitation in the area is between 1750-3000 mm annually, but higher rates of precipitation occur in the volcanic slope and cone of Merapi, located in the northern part of the area (Sutikno 1996, p.2). Fig.33 indicates a relative constant monthly temperature and humidity over the year. The rainfall, also seen in the figure is depending on the monsoon, with a dry period from May to August, which is considered to be a little longer period than Java in general (see Java section).

Fig.33. Monthly averages precipitation for each of the regencies with average monthly temperature and relative monthly humidity given for the whole area (D.I.Yogyakarta) (Source: BPS, Kantor Statistik D.I.Y. 1996., Suharsono et al 1996). During May-September, the number of rainy days for each of the regencies is less than 10 days and more than 10 days during October-April (Tab.8). According to RePPProT (1989), the mean daily Penman evapotranspiration, is relative constant through the year with an average of 4,1 mm/day, and the monthly Penman evapotranspiration is estimated to 1502 mm. The average wind speed within the special province is estimated to 3 m/s, but depends on the topography and distance from the Indian Ocean.

Tab.8. Number of rainy days (1996), in each regency. Regency J F M A M J J A S O N D Kulon Progo 17 17 15 18 7 4 1 6 10 15 19 15 Bantul 20 12 8 14 6 4 2 5 6 9 14 12 Gunung Kidul 14 14 17 15 5 4 3 5 8 12 12 11 Sleman 20 16 15 16 7 3 2 6 8 13 13 13

(Source:Fakultas Kehutanan & Kanwil Kehutanan D.I.Y. 1996)

Vegetation & Land Use There are many kinds of tree species within each of the regencies, such as teak, mahogany, pine, lamtoro (local firewood), hibiscus, coconut and mango trees (App.?). There are also planted trees, especially in the hilly areas, to create community forests, with the aim of promoting the afforestation policy. Acacia is a common tree used for this aim (Oral Setyarso 1998). Totally, an area of about 25,6 ha. (80%) within the special district is covered by forest, distributed different between the regencies (Tab.9). Gunung Kidul is the most forested regency with more than 40% of the area covered by forest, while the regency of Sleman only is covered with less than 12 %, including forest lands.

64 Tab.9. The spatial distribution and quantity of forest for each regency Regency Area Area (%) Volume Density (ha) (m) (m/ha) Kulon Progo 5.881 22,9 243.061 41,32 Bantul 5.667 22,1 173.992 30,70 Gunung Kidul 11.072 43,2 927.106 83,73 Sleman 3.030 11,8 103.667 34,21 Total 25.639 100 1.447.826 56,46 Simplified after Fakultas Kehutanan & Kanwil Kehutanan D.I.Y. 1996. Different types of seasonal crops are grown in the area including paddy rice, cassava, salak pondoh, maize, soy beans, sugar canes, bananas, and potatoes as leading crops (app.5, p.70). These kinds of crops are more commonly cultivated on the Island of Java compared with the other islands. About 19% of D.I. Yogyakarta is covered with wetland, and irrigated sawah (wet paddy rice fields) is the most usual land utilisation type, dominating the flat areas of fertile volcanic deposits, especially in the Sleman regency. More than 50% of the dryland areas is located in the regency of Gunung Kidul (Tab.10) and dryland plantations dominate in the entire special district, mostly occurring in hilly areas and close to settlements. Tegal (dry paddy rice fields) is also common in these areas. Nearly all temporary fallow land (98,2%) and land used for commercial crops (96,7%) can be found in the regency of Kulon Progo (BPS, Kantor Statistik D.I.Y 1996).

Tab.10. Area of wetland and dryland by utilisation in D.I.Yogyakarta (1996), and its distribution for each regency/municipality in percent. Land by Area Distribution for Each Regency Utilisation (Ha) (%) D.I.Yogyakarta K* B* G* S* Y* 1. WETLAND 60,671 17,9 27,6 13,3 40,5 3,21 · Irrigation 50,304 18,2 28,9 5,08 48,9 3,88 · Rain fed 10,307 16,1 21,1 53,4 0,00 0,00 · Others 60 0,00 100 0,00 0,00 0,00 2. NON-WETLAND 257,909 18,5 13,1 54,4 12,7 1,18 · Home Garden 84,28 23,2 23,5 29,1 21,9 3,20 · Dry field/Garden 112,343 16,4 5,97 73,5 5,53 3,56 · Pond 295 6,44 21,0 20,7 50,2 3,73 · Temporary fallow land 112 98,2 0,00 1,80 0,00 0,00 · Private woods/Forested lands 18,406 14,2 10,6 63,8 6,60 0,00 · Forest 16,527 6,19 56,4 79,9 8,08 0,00 · Commercial Crops 1,649 96,7 0,00 32,5 0,00 0,00 · Others 23,975 19,2 19,4 36,1 23,8 149 TOTAL 318,58 18,4 16,0 46,6 18,0 1,00 Source: BPS, Kantor Statistik D.I.Y. 1996. * K-Kulon Progo, B-Bantul, G-Gunung Kidul, S-Sleman, Y-Yogyakarta

Statistic figures from 1993-1996 (BPS, Kantor Statistik D.I.Y. 1996) indicate relative similar land utilisation conditions in the area through the years. Since 1995 a change concerning commercial crops lands, according to statistics, occurred in the regency of Gunung Kidul, which at the moment have 55 ha compared with none in 1994. This because of conversion on temporary fallow land (Oral Setyarso 1998). The regency of Gunung Kidul also embraces the majority of the forest-covered areas and private forestland.

Soils 65 High fertile volcanic soils mixed with minerogen ashes dominates the slopes of Mt. Merapi, in the northern part of the province, and Regosols (inceptisols &entisols) is the most common soil type, with a pH-value between 5,5-6,5 (Peta II.3.Sebaran janis-janis tanah di prov. D.I.Y, scale 1:250.000 1992). A recent eruption from the volcano (1994) has resulted in a soil depth of more than 2 m in some places. The regency of Gunung Kidul, stretching from the foot of the volcanic slope down to the Indian Ocean in the south, in general consist of low drainage, and more acid litosols (entisols), with exception for the karstic plateau of Wonosari, located in the central part of the area (Peta Dati II, Jenis Tanah, Kabupaten GK, scale 1:100.000 1988/89). grumosols (vertisols), litosols (entisols) and rensina (entisols) having a pH-value between 5,5- 7,5 dominate this area (Peta II.3.Sebaran janis-janis tanah di prov. D.I.Y, scale 1:250.000 1992). Similar soils can be found in the west part of the district, including the regency of Kulon Progo and major parts of the . (Peta Dati II, Jenis Tanah, Kabupaten GK, scale 1:100.000 1988/89) with a pH-value between 7,5-8,0 (Peta II.3.Sebaran janis-janis tanah di prov. D.I.Y, scale 1:250.000 1992).

Hydrology During periods of heavy rainfall, flooding occur in the down stream areas, especially of the largest rivers Progo, Opak (Fig.34), and Serang, causing erosion on the river banks and the burying of rice fields with deposits. Droughts is the main problem of the karstic area, especially concerning water supply, although some dolines are filled with rainwater, function as reservoirs for the local people (Sutnikno 1996, p.8). This area also embrace several underwater rivers, as a result of the land upheaval, which supports the area with water. In general, the groundwater level in the regency of Bantul and Kulon Progo is shallow with a depth less than 7 meter. The middle slope of Merapi has a groundwater depth between 7-15 m reaching more 15-25 m in the volcanic footplain. The Wonosari plateau in the regency of Gunung Kidul has a groundwater depth between 7-15 m, while the surrounding areas within the regency are non-aquifer (Peta Airtanah D.I.Y. scale 1:250.000 Laboratorium Kartografi, Fakultas Geografi, Universitas Gadjah Mada. Yogyakarta). Fig.34. River Oyo running through in Playen, Gunung Kidul. (Photo M. Enryd 1998)

3.2 Population Status Demography

66 As a result of the large concentration of universities and other education centres the Special Province Yogyakarta is one of the most densely populated areas in Indonesia, with a density of 999,87 persons per km2 (Tab.11.). The province further attracts tourists because of its specific history, which also contribute to a higher density of people.

Tab.11. Population distribution, density and growth for each regency/municipality in D.I.Yogyakarta, 1996, and its total land area and administrative sub-divisions. Total Numbe Numbe Total popu- Male Female Popu- Popu- Total Total Regency/ land r of r of lation popu- popu- lation lation urban rural Municipality area sub- villages (Thousand lation Lation density growth popu- popu- (km2) district s) (%) (%) (pers/km (%) lation lation s 2) (%) (%) Kulon Progo 586,3 12 88 431,6 48,7 51,3 736 0,69 8,00 92,0 Bantul 506,9 17 75 748,5 48,8 51,2 1,476,80 1,07 59,3 40,7 Gunung Kidul 1,485 15 144 729,7 48,9 51,1 491,2 0,68 3,8 96,2 Sleman 574,8 17 86 804,4 49,3 50,7 1,399,34 1,27 48,2 51,8 Yogyakarta 32,50 14 45 471,3 51,5 48,5 14,502,62 1,07 100 0,00 D.I.Yogyakart 3,185,80 75 438 3,185,474 49,4 50,6 999,9 0,98 42,9 57,1 a (Source: BPS, Kantor Statistik D.I.Y. 1996. and Departemen Pertanian, Kantor Wilayah D.I.Y. 1996).

One problem is within the special province is the increase in population pressure (TP) Calculations of TP in areas with agroforestry as land utilisation type (Tab.12) show that especially the regency of Sleman are under an intensive influence of TP with about 85% of all villages included. Kulon Progo is although under less influence. Bantul and Gunung Kidul also so far comprise a less pressure.

Tab.12. TP-Calculations based on Agroforestry within each of the Regencies. Total TP>1 TP<1 Regency Number of Villages Gunung Kidul 13 6 7 Bantul 17 7 10 Sleman 15 13 2 Kulon Progo 12 1 11 (Source:Suharsono 1996)

Socio-economic & Cultural Parameters

67 Many people within the Special province are in some way involved in agriculture giving a big variety of incomes among the people. According to statistics (BPS, Kantor Statistik 1996) people with the highest income, not surprisingly, tend to live in the city. Among farmers, households located on the volcanic soils of Mt. Merapi in general have a more high income, sometimes reaching more than 3-10 times more, compared with the other areas. The higher education levels are concentrated among the city people, and people living in the surrounding regencies of the municipality Yogyakarta in general have lower education level. The reason of that is lower income together with more traditional and 'simple' thinking. Although, research made in the area (Bahan seminar 1996) indicates on a relationship between education and productivity. Farmers with agroforestry that get educated in agribusiness will according to the research be able to use their natural resources better and also to make a better profit, but people that get educated and adept new techniques with success also tend to move to the city renting out their land. The traditional thinking among farmers within the regencies is very strong, and the use of plants for a wide range of medicinal cures is common. These plants are usually grown in homegardens and are usually cultivated for their role in religious ceremonies. Alang-alang (wild grass) sometimes regarded as a scourge for some, is managed and sometimes cultivated among traditional farmers to produce fodder for animals and thatching. The traditional belief on Mt. Merapi is also that the topmost grasslands on the volcano are the property of the spirits and can not therefore be cut (Whitten et al. 1996, p. 676-677).

2. TP-formula

68 TP (=population pressure) is a common formula used in Indonesian socio-economic analysis to calculate the carrying capacity of the land. This formula can be applied on any kind of land use.

TP >1: Severe problems, TP = 1: Under control, TP <1: Good conditions.

3. Universal Soil Loss Equation (USLE) - Calculations

Tab.13. Soil Loss Estimations within the Study Area. Site R K LS C P USLE (USLI) 1 474.97 0.20 289.82 0.01 1.00 275.31 27530.64 2 474.97 0.10 0.8400 0.60 0.40 9.5300 39.71000 3 474.97 0.20 1.0000 0.20 0.50 9.500 94.99000 4 546.64 0.20 188.27 0.60 0.04 494.00 20583.54 5 546.64 0.30 1.0000 0.20 0.40 13.120 163.9900 6 752.96 0.20 1.0000 0.20 0.40 12.050 150.5900 7 492.56 0.20 0.8900 0.20 0.04 0.7000 87.74000 8 321.16 0.15 0.7000 0.15 0.30 1.5200 33.85000 9 338.80 0.30 14.320 0.15 0.40 87.320 1455.340 10 321.16 0.20 12.750 0.15 0.40 49.14 819.0100 11 429.55 0.20 12.970 0.15 0.40 66.860 1114.400 12 429.55 0.20 11.130 0.15 0.40 57.370 956.1100 13 418.68 0.15 10.220 0.15 0.40 256.640 641.5900

A = R X K X LS X C X P A = Soil Loss in mass/unit area (ton/ha/year) R = Rainfall and Runoff erosivity Factor K = Soil Erodibility Factor L S = Topographic Factor for Slope Length and Steepness C = Crop Management Factor* P = Erosion Control Practices Factor*

· (USLI) = USLE-calculations excluding the P-factor · The USLE-calculations are based on the top layer (Depth: 5cm) from the soil samples. · Classification (ton/ha/year): Very Low (<15), Low (15-60), Moderate (60-80), High (180-480), Very High (>480) *(Source: Department of Forestry, Yogyakarta Daerah Aliran Sungai Opak-Rencana Teknik Lapangan Rehabilitasi Lahan dan Konservasi Tanah Sub Daerah Aliran Sungai Oyo 1993)

69 4. Questionnaire

². Identity of Respondent 1. Location: a. Village: b. Sub-District: c. Regency: 2. Name: 3. Sex: 4. Age: 5. Number of Members in the Household:

²I. Land Conditions 1. What is the approximately size of the cultivated land area that you own? 2. Is all land under cultivation? If not, what is the reason of that? 3. What kind of crops or vegetation do you cultivate? In what size is the cultivation? Since when have you cultivated this land? 4. Why did you choose this kind of cultivation? 5. What is your main crop? 6. Would you like to introduce another crop or vegetation in the future? If yes, what kind? If not, any reason of that? 7. Have you ever had another kind of cultivation in the past? If so, when and why did you change? 8. Do you think that your land is more fertile now or earlier? If yes, since when? If not, since when? 9. Do you have any problems with soil loss because of the rainfall, erosion, decrease in fertility, or other? If so, what scale? If so, do you know what the problem is? 10. What is the most time consuming with your cultivation? 11. What is the most difficult work to do within your cultivation? 12. Do you use fertilisers? Insecticide? Pesticide? Weedkiller? 13. Have you done anything to prevent or reduce erosion? If so, what did you do? 14. Do or did you get any help from the government to prevent or reduce erosion? If so, what kind of help? (Financial help, management programs etc.) When?

15. What kind of management do you use for your crops or vegetation? · Rotation Row crop cultivation Grazing land management Forest management · Cover crops · Strip cropping · Multiple cropping Sequential? Intercropping? High density planting · Mulching · Revegetation Afforestation Reforestation 70 Natural revegetation · Agroforestry 16. What kind of management do you use for the soil? · Apply organic matter · Tillage practices Conventional tillage No tillage Strip tillage Mulch tillage Minimum tillage · Soil stabilisers? 17. What kind of mechanical methods do you use? · Contouring · Contour bounds · Terraces · Waterways · Stabilisation structures

²II.Socio-Economic Conditions 1. Are you able to get some income from your cultivation? If so from what? a. Food crops b. Vegetables c. Fruits d. Fuel wood e. Wood for construction f. Honey bee g. Others, What? 2. Are you a full time farmer? If not, are you working anywhere else? 3. Do any another members of your household have some side incomes? 4. Do you have an employee helping you with your cultivation? 5. Are you able to make a profit by selling? If so what do you sell? 6. How much is the profit for your cultivation? 7. Do you have enough land to support one household? 8. Is your cultivation irrigated? If no, other kind of water resources? 9. Do you use firewood? If yes, from where?

71 5. Common Crops & Vegetation Types within the Study Area

Tab.14. Plant Species within the Study Area, and their Main Use. No Indonesian English Latin Main use 1 Pinus Pine Pinus merkusii Pulp, Gum, Furniture 2 Salak Pondoh Zalacca palm Zalacca sp Fruit (food) 3 Rotan Rattan Calamus sp Furniture 4 Paku-pakuan Fern Marattiaceae 5 Ubi Kayu Cassava Manihot utilisima Root crop (food) 6 Padi Paddy rice Oryza sativa Cereal (food) 7 Kelapa Coconut Cocos nucifera Fruit (food & drink), wood (construction) 8 Sukun Bread fruit Artocarpus communis Fruit (food) 9 Melina Gmelina Gmelia arborea Pulp 10 Nangka Jack fruit Artocarpus integra Fruit (food), furniture 11 Meniran Phyllanthus niruri 12 Secang Caesalpinia sappan Fire wood 13 Sengon Paraserianthes falcataria Pulp, furniture 14 Kaliandra Caliandra calothyrsus Fodder 15 Kopi Coffee Coffea canephora Bean (food & drink) 16 Randu Cotton tree Ceiba pentandra Clothes 17 Melinjo Gnetum gnemon Fruit, leaves (food) 18 Jagung Maize Zea mays Vegetable (food) 19 Rumput Teki Cyperus rotundus Fodder 20 Putri malu Sensitive plant Mimosa pudica 21 Mindi Melia azadarach Furniture 22 Apokat Avocado Persea americana Fruit (food) 23 Coklat Cacao tree Theobroma cacao Bean (food & drink) 24 Gamal Gliricidea sepium Firewood 25 Sonokeling Dalbergia latifolia Furniture 26 Formis Acacia Acacia auriculiformis Firewood 27 Leda Eucaliptus Eucaliptus alba Furniture 28 Klampis Acacia Acacia tomentosa Firewood 29 Jati Teak wood Tectona grandis Construction, furniture, plywood 30 Kayu Putih Melaleuca leucadendron Distillated oil (medicine) 31 Kerinyu Eupathorium pallescens 32 Alang-alang Imperata cylindrica Fodder 33 Kacang tanah Peanut Aracis hypogaea Nut (food) 34 Pisang Banana Mimosa pudica Fruit (food), leaves (wrapping) 35 Bambu Bamboo Bambusa sp Furniture 36 Kalanjana King grass Panicum muticum Fodder 37 Petai Parkia speciosa Vegetable (food), Firewood 38 Rumput Gajah Elephant grass Pannisetum purpureum Fodder 39 Lamtoro Leucaena leucocephala Firewood 40 Mahoni Mahogany Swietenia mahagoni Furniture 41 Rambutan Nephelium lappaceum Fruit (food) 42 Johar Casia siamea Firewood (Source: Susanti 1998)

72 6. Soil Survey

Sources to survey sheet # Soil profile description: FAO Soil description (1988). # Subsoil description (texture): RePPProT (1989). # Slope inclination, exposure and form: FAO Soil description (1988). # Erosion type (and cause): Morgan (1994). # Soil erosion classification: (Dep. of soil science UGM): None, slight, moderate, severe, extreme • Degree of deposition (Dep. of soil science UGM): none, slight, moderate, severe, extreme • Deposited material (Dep. of soil science UGM)

# Field check within a 15 m radius: FAO soil description (1988), Ari Susanti, Wijonarko Suhari, local farmers. • Exposure of tree roots • Crusting on the soil surface • Formation of splash pedestals • Type of ground cover • Density of ground cover (%) • Type of canopy cover • Density of canopy cover (%)

Soil samples

Only soil sample: 1 soil sample from A respective B-horizon, if any pH-test from topsoil and subsoil (1s + 4 dest.) Colour, brightness, intensity classification with Munsell colour chart Classification of texture

Soil profile description: 1 Sample from A, B, respective C horizon, if any, for soil profile description pH-test from A, B, respective C horizon (1s + 4 dest.) Colour, brightness, intensity classification with Munsell colour chart Classification of texture, structure and wetness Shear strength test from horizon, if possible. Measure of infiltration rate (FAO Soil description etc.)

73 74