ISSN 0024-9521 IJG Vol. 46, No.1, June 2014 (89 - 98) © 2014 Faculty of Geography UGM and The Indonesian Geographers Association Land use planning of paddy field using geographic information system and land evaluation in West Lombok, Indonesia Widiatmaka, Wiwin Ambarwulan, Rudi P. Tambunan, Yusanto A. Nugroho, Suprajaka, Nurwadjedi, Paulus B.K. Santoso Received: 07 01 2014 / Accepted: 22 01 2014/ Published online: 30 06 2014 © 2014 Faculty of Geography UGM and The Indonesian Geographers Association Abstract Planning analysis to increase rice production either through intensification of existing paddy field area or ex- tensification in potential land area was conducted in West Lombok Regency, West Nusa Tenggara Province, Indonesia. Existing paddy field was delineated using high-resolution data from IKONOS imagery of 2012. Land use and land cover outside existing paddy field were interpreted using SPOT-5 imagery of 2012. The Automated Land Evaluation System (ALES) was used for land suitability analysis for paddy. The results are interpreted in terms of the potential of paddy field intensification in existing paddy field area and the potential of extensification in land potentially used for paddy field. The result of analysis showed that in West Lombok Regency, there are still possible to do intensification and extensifica- tion of paddy field to increase rice production in order to improve regional food security. Keywords: Automated Land Evaluation System, soil survey, land quality, land characteristic, image interpretation. Abstrak Analisis perencanaan peningkatan produksi padi melalui intensifikasi pada lahan sawah eksisting dan eksten- sifikasi pada lahan yang potensial disawahkan dilakukan di Kabupaten Lombok Barat, Provinsi Nusa Tenggara Barat, Indonesia. Penggunaan lahan dan tutupan lahan diinterpretasi menggunakan citra SPOT-5 tahun 2012. Sawah eksisting didelineasi menggunakan citra beresolusi tinggi IKONOS tahun 2012. Evaluasi lahan menggunakan Automated Land Evaluation System (ALES) digunakan untuk analisis kesesuaian lahan untuk padi sawah. Hasil analisis menunjukkan bah- wa di Kabupaten Lombok Barat, masih dimungkinkan dilakukan intensifikasi pada lahan sawah eksisting dan ekstensifi- kasi pada lahan potensial sawah untuk peningkatan produksi beras dalam rangka peningkatan ketahanan pangan wilayah. Kata kunci: Sistem evaluasi lahan otomatis, survey tanah, kualitas lahan, karakteristik lahan, interpretasi citra. I. Introduction Indonesia’s dependence on rice as staple food is very which is only about 6.9% of the land area of Indonesia, high, and even worrisome when viewed from the spatial contributing to 52.32% of Indonesia’s rice production. distribution of rice production locations. According to On the other side, Java Island is an island with the recent statistical data [BPS, 2013a], the harvested area highest population density, resulting high pressure on of paddy field in Java Island in 2012 is 6,165,079 Ha, the existing paddy field. Land conversion, according to constituted of 46.89% from the total Indonesian har- the analysis using the official statistical database from vested area. Such harvested area produces rice as many 1989 to 2000, has caused a reduction in paddy field as 34,404,557 tons, or constituted of 52.32% from the area, from 3.48 million Ha in 1988 to 3.37 million Ha in national rice production. In other words, Java Island, 1999 [Abdurachman et al., 2005]. The Java paddy field which is converted during 1978-1998 reached 1.07 mil- Widiatmaka Dept. of Soil Sciences and Land Resources, Bogor Agricultural lion Ha, which means that there was a depreciation of University, Indonesia 8,000 Ha/year or 23% area/year [Irawan, 2004]. Such Email: [email protected]; [email protected] data illustrate the rice staple food insecurity. Land con- W. Ambarwulan, Suprajaka, Nurwadjedi version which generally occurs in the fertile agricultural Geospatial Information Agency, Indonesia land would threaten the national food security [Irawan, R. P. Tambunan 2005]. If this conversion trend continue, there will be Center for Applied Geography Research, University of Indonesia, a dramatic escalation of the country’s dependence on Indonesia imported rice. According to Agus et al. [2006], to main- Y. A. Nugroho tain self sufficiency for the next twenty years, Indonesia Alumny, University of Gadjahmada, Indonesia has to curb the current conversion rate of above 100,000 P. B. K. Santoso Ha/year to less than 29,000 Ha/year. For each hectare of Center for Agricultural Data and Information, Ministry of the converted paddy field in Java Island, 2.20 Ha, new Agriculture, Indonesia paddy field has to be developed at the outside of the LAND USE PLANNING Widiatmaka et al. island to compensate the yield loss due to decreasing increasing the productivity of rice remains to be the productivity of the current paddy fields. major challenge for local governments and researchers Various efforts are needed to ensure Indonesian in this countriy. food security, such as by increasing rice production, controlling the rice consumption levels as well as con- 2. The methods trol of rice needs. One of the efforts which can be done The research was conducted in West Lombok Regency, to increase the production are intensification of the ex- West Nusa Tenggara Province, Indonesia. Geographi- isting paddy field and, if possible, extending paddy field cally, the regency is located at 115.46°-116.20°E, and to the potential land, especially in outside Java Island. 8.25°-8.55°S. The research location is presented in Fig- Efforts to increase the production in a specific region ure 1. Average annual rainfall of the region is 1,586 mm, are needed, at least so that an area will not depend on and average monthly rainfall is 132.2 mm, while aver- the other areas, which then will reduce the actual na- age number of rainy days is 14.1 days in a year [BPS, tional food security in the aggregate. Even if possible, 2013b]. an area should provide a surplus which can contribute Land cover of the regency was first delineated using to national food security. However, such intensification SPOT-5 imagery acquired in 2012. Image classification and extensification often meet with many challenges. was done by supervised classification, followed by field The main threats to the future food security include checking. The classification was done using ERDAS decreasing agricultural land, depleting water resources, Imagine software. Imagery analysis produces 28 type of declining trends in soil fertility and productivity, deple- land use and land cover. However, to simplify the result, tion of groundwater table [Devi & Ponnarasi, 2009] as the land use and land cover were grouped into 13 type well as, in case of Indonesia, inefficient land resources of land use and land cover. For existing paddy field, a utilization. more accurate data were used for map correction based West Lombok Regency is one of regencies in Lom- on Ministry of Agriculture agricultural data. This data bok Island where its natural resources provide high was produced from paddy field measurement activity possibilities for paddy field intensification as well as using high resolution imagery IKONOS acquired in extensification. According to the latest statistical data 2012. [BPS, 2013b], West Lombok Regency is able to pro- A soil survey was conducted in 2013 in the study duce 152,686 tons of rice from irrigated paddy fields. area as a part of survey conducted in the whole island of That amount, when added with 4,833 tons from non- Lombok, initiated by Geospatial Information Agency, irrigated paddy field production, and with a population Indonesia. In that survey, 103 soil samples were taken of 606,044 people in 2011, is expected to be adequate from whole Lombok Island. The site sample locations in for self-sufficiency of the regency, and even it can still West Lombok Regency, as well as in other regencies in provide a surplus as an addition to the regional and whole Lombok Island are given in Figure 1. national food security. However, an increasing number The analysis of physical and chemical [Widiatmaka of population which is faster than the growth of pro- et al., 2013a] soil properties was performed in Labora- duction in the future, may cause a productivity reduc- tory of the Department of Soil Science and Land Re- tion, which in turn can reduce the regional food secu- sources, Faculty of Agriculture, Bogor Agricultural rity. Similar phenomena has been reported in previous University and Laboratory of Center for Agricultural study in Nusa Tenggara Province [Nazam et al., 2011]. Land Resources, Bogor, Indonesia. The results of the Therefore, efforts to increase the production should survey were drawn on 1:25,000 map available at Geo- be implemented, at least to keep pace with population spatial Information Agency, Indonesia. In this paper, growth. only the result in West Lombok Regency is presented. Both intensification and extensification need to be The land suitability for paddy field was analyzed -us coupled with knowledge of the land properties. Efforts ing Automated Land Evaluation System (ALES) [Ros- to increase rice production should be done by site-spe- siter, 2001]. Maximum limitation method was used for cific management. For example, Phosphate (P) fertilizer the land evaluation. In this method, degree of limitation needs to be done only on land with P deficiency. In term of the land use was imposed by land characteristics on of precision, land management should be done in the the basis of its permanent properties and required cri- right time, amount, and place [Robert et al., 1994], as terias [De la Rosa and Van Diepen, 2002; Armanto et well as the source and manner [Khosla, 2010]. al., 2012]. Land suitability criteria for paddy field was The objective of this paper is to present an analy- structured by bibliographical studies [Hardjowigeno sis and planning to increase rice production, either and Widiatmaka, 2007; Djaenudin et al., 2003; FAO, through intensification on existing paddy fields or 1983; Ritung et al., 2007].