Move to Organic Farming Systems: Chemical and Physical Soil Properties of Organic and Conventional Vegetables Reasons

Sukristiyonubowo1*, Damasus Riyanto2 and Sugeng Widodo2

1Indonesian Agency for Agricultural Research and Development , Soil Research Institute, Tentara Pelajar Street no. 12 Bogor; Telp: +6281226277259 ; 2Indonesian Agency for Agricultural Research and Development, Jogyakarta Assessment Institute for Agricultural Technology, Stadion Maguwohardjo Street no. 22 Karangsari,Wedomartani-Ngemplak, Sleman. Jogyakarta Special Region

Corresponding Author: [email protected]

Abstract Conventional agriculture is an agricultural system based on high input materials such as chemical fertilizers and pesticides that can damage the properties of soil and ultimately reduce soil productivity. Meanwhile, organic farming is defined as a process that respects environmental sustainability, from the production stage to the packaging process. The study was conducted in Kopeng Village, Semarang Regency, Central Java from October 2017 to April 2018. The objective this research was to study soil chemical-physical characteristics of vegetables organic and conventional farming systems in Kopeng village, Semarang District, Central Java Province. One kilo gram of composite soil samples and ring soil samples were taken from each furrow in October 2017. The results showed that soil pH (5.70 ± 0.2), organic C (3.07 ± 0.31 %), total N (0.37 ± 0.03 %), potential phosphate(200 ± 89 ppm) and potassium extracted with HCl 25% (72 ± 24 ppm) were more superior in organic fields compared to conventional systems. The similar results were shown in the physical properties of organic vegetable cultivation that was better than conventional, such as bulk density (0.80 ± 0.04 g/cm3), particle density (1.96 ± 0.05 g/cm3), total pore (65.16 ± 1.22 %), rapid drainage (30.40 ± 2.87%) and slow drainage (4.74 ± 0.12%)

Keywords: conventional vegetables, organic vegetables, soil chemical and physical properties

1. Introduction In Indonesia, vegetables and fruits are not only crop with high economy value and healthy foods, but also source of income providing jobs for most villagers.Today a healthy lifestyle has made organic farming a trend of attractive and profitable business activities in Indonesia, especially vegetable and fruit products that are widely consumed by households on a daily basis. In terms of consumers, health reasons have become a motivation that drives increased consumption of organic food, so that organic farming activities also grow. Consumers of households buying organic food products are not just to meet food needs, but more importantly the benefits of organic food products. By definition, the term of organic agriculture refers to a process that uses methods respectful of the environment, from production stages through the handling and processing. Thus, it is not merely concerned with a product, but the whole system used to produce and deliver the product to the

162 Proceeding The International Seminar on Tropical Horticulture Horticulture for The Quality of Life Bogor, December 10th, 2018

ultimate consumers (Anonymous 2004). Consequently, organic farming systems avoid applications of chemical fertilizers and pesticides, rely on organic inputs and recycling for nutrient supply, and emphasize on cropping system design and biological processes for pest management (Rigby and Cáceres 2001). Thus, they can reduce some negative effects attributed to conventional farming (Oehl et al. 2004; Mäder et al. 2002; Reganold et al. 1987). Soil quality assessment including chemical, physical and biological properties has become a model to determine soil function (Sukristiyonubowo et.al. 2011). According to Doran and Parkin (1994) soil quality is defined as the capacity of the soil to function within ecosystem boundaries to sustain biological productivity, maintain environmental productivity, and promote plant and animal health. So far, Sharma et al. (2008) reported that in the past soil quality is understood as inherent soil capacity to supply essential plant nutrients. Consequently, profitable and sustainable agriculture management should be addressed at supplying sufficient nutrients for optimum crop growth and development as well as farmers income, with keeping losses to environments at the minimum level. Yan et al. (2007) and Haynes (2005) stated that soil organic matter is considered to be a key attribute of soil quality because of its role on chemical, physical and biological properties and process in soil. Therefore, basically soil quality is the ability of a soil to perform the functions necessary for its intended use. Thus, indicators include dynamic soil properties or management, chemical (nutrients and carboncycling), physical (aggregate stability, available water capacity, bulk density, infiltration, slaking, crust, soil structure and macrospores) and biological (respiration, enzyme, microbial community, and phospholipids fatty acids) aspects (USDA 1999; Herrick 2000; Doran and Zeiss 2000). According to Amalia (2011) soil quality in paddy field is combining among soil organic carbon (SOC) and total N content with enzymedehydrogenase, β- glucosaminidase activity and microbial biomass C (MBC) as well as phospholipids fatty acids (PLFA) are suitable indicators, while in vegetables field PLFA is not considered as suitable parameter. In some countries, research in organic farming system have been developed both in plot, farm and community scales with different purposes. Some advantages of organic rice farming are reported by researchers. Prakhas et al. (2002) reported that rice planted in organic technology has better inmilling and cooking quality like total and head milled rice recovery, protein content, kernel elongation and lower in amylose content than cultivated inconventional system with commercials fertilizers and pesticides. Zhang and Shao (1999) reported that higher protein grains content will result in higher head rice recovery and lower amylose content. Chino et al. (1987) found that in the organic cultivation, the asparagine’s content of plant phloem sap is significantly lower than in conventional systems. Kajimura et al. (1995) reported that the low densities of Brown Plant Hopper and White Backed Plant Hopperare observed in organic fields. Similar finding was reported by Alice et al. (2004). In line with the soil, organic farming is usually associated with a significant higher level of biological activities and soil organic matter than in green revolution technology (Oehl et al. 2004; Mader et al. 2002; Hansen et al. 2000; Stolze et al. 2002). In fact, there are still limited studies oncomparing organic versus conventional systems (Hasegawa et al. 2005).The objective this research was to study the soil chemical-physical characteristics of vegetables organic and conventional farming systems in Kopeng village, Semarang District. Central Java Province.

Proceeding The International Seminar on Tropical Horticulture 163 Horticulture for The Quality of Life

Bogor, December 10th, 2018

2. Materials and Method Research was carried out from October 2017 to April 2018. Composite soil samples of 0-20 cm in depth were taken in October 2017, before land preparation. Samples were taken from three furrows of 1 m x 10 m, as replications.In each replication, soil composite wascollected from ten sampling points at every furrow and mixed. These samples were submitted to the Analytical Laboratory of the Balai Pengkajian Teknologi Pertanian, Jogyakarta for analyses of chemical and physical properties of the soils. Chemical analyses included the measurement of pH (H20 and KCl), organic matter, phosphorus, and potassium, Organic matter was determined using the Walkley and Black method, pH (H2O and KCl) was measured in a 1:5 soil-water suspension using a glass electrode, total P and soluble P were measured colorimetrically using HCl 25% and Olsen methods, respectively. The total K was extracted using HCl 25% and subsequently determined by flame- spectrometry. (Soil Research Institute, 2009). Physical analyses included the measurement of water level, particle density (PD), bulk density (BD) and total pore space. Water level was measured by Gravimetric method, particles density was measured by Richards and Fireman method (1943), bulk density was measured by Richards method (1947) and total pores space was measured using De Boodt method (1967). All measurement of physical analysis was adopted by Indonesian Soil Research Institute (2009). In the organic cultivation, the farmers using chicken manure and straw compost as much as 2-3 tons/ha/season, while in the conventional farming systems the farmers add 100 kg urea, 50 kg SP-36 and 50 KCl /ha/season plus manure less than 1 ton/ha/season.

3. Results and Discussion Soil Chemical Fertility The soil fertilities discussed were only soil chemical and physical parameters.The soil chemical data are presented in Table 1. In general, the soil chemical fertilities in vegetables organic farming including soil pH, C-organic (%), N total (%), P and K extracted with 25 % HCl were tremendously improved compared to conventional farming system. These due tocontinuous addition of manure or compost. In organic vegetables farming system, the soil pH was 5.90 ± 0.20, the soil organic carbon was 3.18 ± 0.31%, N-total was 0.37± 0.02% and P extracted with 25 % HCl was 200± 89 mg 100 gr-1, as well as K extracted with HCl became 72 ± 24 mg 100 gr-1compared to conventional vegetables farming system, which was the soil pH was 4.90 ± 0.00, the soil organic carbon was 2.18 ± 0.21%, N-total was 0.25± 0.02 % and P extracted with 25 % HCl was 132 ± 16 mg 100/g, as well as K extracted with HCl became 39 ± 7 mg 100/g(Table 1.) In the year 2017, the pH of the soil in organic rice fieldwas 5.90 and classified as slightly acid to neutral. The neutral of the soil in organic vegetables field may be due to continue applying organic manures. Moreover, the neutral of soils may be due to accumulations of organic acids like fulvic and humic acids released by organic materials (compost and manure) added by the farmers. In contras, in conventional systems, the soil pH was about 4.90. This acidity of the soils may be due to accumulations of mineral fertilizer (urea) applied by the farmers. The level of

164 Proceeding The International Seminar on Tropical Horticulture Horticulture for The Quality of Life Bogor, December 10th, 2018

soil organic carbon (SOC) and total N was classified as high in the organic vegetables farming system, but in the conventional vegetables farming systems was considered as medium to high. These was due addition of manure or compost in organic vegetables farming system. The same reason given by the farmers in conventional farming system. In the conventional vegetables farming system the farmer also added the manure less than 1 ton/ha/season. The soil organic carbon (SOC) and total N in organic vegetables farming system were 3.18±0.31% for soil organic carbon and 0,37± 0.03 % for the N total, and in the conventional vegetables field about 2.18 ± 0.21% for soil organic carbon and 0.25 ± 0.02% for the total N. According to Sommerfeldt et al. (1988) and Clark et al. (1998) reported that the higher soil organic matter (SOM) levels find in the soils managed with manure and cover crops than in soils without such inputs. For the conventional vegetables farming system, the total P or potential P extracted with HCl 25% classified as medium, and this was lower than in organic vegetables cultivation systems, suggesting that application of organic fertilizersa about 2– 3 tons manure/ha/season in organic system were more superior than application of mineral fertilizer(50 kg SP- 36 /ha/season) in conventional vegetables fields.Thus, it can be concluded that the total P or potential P extracted with HCl 25% in the conventional rice farming system was lower compared tothe organic vegetables farmings, because of P fixation(becameAl-P, Fe-P or Mn-P due to the lower pH in conventional vegetables farming system (pHH20: 4.90). Table 1. The soil chemical properties of vegetables farming systems in Kopeng village, Semarang Regency, Central Jave Province Farming Parameters Replication Means systems I II III Soil pH 6.10 5.90 5.70 5.90 ± 0.20 C- organic ( % ) 3,52 3.12 2.90 3.18 ± 0.31 Organic N-Total ( % ) 0.39 0.39 0.34 0.37 ± 0.02 Farming P Extracted with HCl (ppm) 303 157 140 200 ± 89 K extracted with HCl (ppm) 56 60 101 72 ± 24

Soil pH 4.90 4.90 4.90 4.90 ± 0 C- organic ( % ) 2.18 2.52 1.85 2.18 ± 0.21 Conventional N-Total ( % ) 0.26 0.26 0.22 0.25 ± 0.02 Farming P Extracted with HCl (ppm) 150 127 120 132 ± 16 K extracted with HCl (ppm) 53 39 26 39 ± 7

Total K in the organic vegetables farming system was about 72 ± 24 mg 100/g and classified as the highest and in conventional farming systems about 39 ± 7 mg 100/g, indicating that application about2-3 ton/ha/season manure or compost was enough to increase the total K in the soil. It was also suggesting that compost applied in the organic rice farming was rich in K content. Whereas, the totalK in the soil ofthe conventional vegetables farming system was considered low indicating addition of about 50 kg KCl/ha/ season cannot increase the total K in the soil. Clark et al. (1998); Rasmussen and Parton (1994) and Wander et al. (1994) also reported similar observations. Therefore, it may be concluded that soil fertility in the organic vegetables farming systems in general were better than in conventional vegetables farming systems including the pH,organic matter content (nitrogen content) and P and K concentrations. In addition, in theconventional vegetables farming systems applications of proper mineral fertilizers to improve inherent soil fertility leading to

Proceeding The International Seminar on Tropical Horticulture 165 Horticulture for The Quality of Life

Bogor, December 10th, 2018

vegetables yield is needed. Furthermore, the importance of organic sources including straw compost, manures and leguminous green manure crops in improving soil chemical and physical properties have also received more attention in recent times (Clark et al. 1998; Hasegawa et al. 2005; Landa et al. 1992; Mandal et al. 2003; Ray and Gupta 2001; Whitbread et al. 2000).

Soil Physical Properties The soil physical parameters are presented in Table 2. The texture of the soil was loam both in organic vegetables farmings and in the conventional farming systems. The soil physical analysis sampled in 2017 showed that in the organic vegetables field, the soil properties including bulk density, particle density, soil porosity and permeability were better than in the conventional vegetables field. In vegetables organic cultivation, the bulk densitywas 0.80± 0.04 g/cm3compared to conventional vegetables farming was 0.87 ± 0.08 g/cm3, the particle density in organic fields was 1.96 ± 0.05 g/cm3 in the conventional was 2.09 ± 0.09 g/cm3, the soil porosity in organic was 65.16 ±1.22 % and in conventional system was 63.65 ±0.15 % and the fast and slow drainage inorganic vegetables farming was 30.43 ± 2.87 and 4.74 ± 0.12, and in conventinal vegetables was 24.03 ± 1.69 for fast drainage and 5.72 ± 0.12 for slow drainage. The conventional vegetables farming system was slightly different with the organic rice farming system, but in organic system was still better than in conventional system. This can be happened, because soil organic matter could arrange aggregates incorporated each other and physically becoming stabilized within macroaggregates.

Table 2. The physical soil properties in organic and conventional vegetables farming system at Kopeng Village, Semarang Regency Replication Means Farming systems Parameters I II III Bulk Density 0.83 0.81 0.75 0.80 ± 0.04 Particle Density 1.93 1.93 2.03 1.96 ± 0.05 Organic Farming Total Pores 68.50 63.87 63.10 65.16 ± 1.22 Fast Drainage 33.70 29.33 28.27 30.43 ± 2.87 Slow Drainage 4.60 4.36 4.46 4.74 ± 0.12 Bulk Density 0.96 0.86 0.80 0.87 ± 0.08 Particle Density 2.15 2.14 1.98 2.09 ± 0.09 Conventional Total Pores 63.73 63.76 63.48 63.65 ± 0.15 Farming Fast Drainage 22.10 25.23 24,78 24.03 ± 1.69 Slow Drainage 5.63 5.67 5.86 5.72 ± 0.12

Hence the soil was more porous and total soil porosity was higher compare to the soil structure in the conventional rice. According to Pirngadi (2009) the organic matter applied to the rice fields can elevate the water holding capacity, improve the soil structure to be crumbly, prevent the soil agregates become more slowly. In addition, the soil with enough C soil content can easily improve soil tillage and usually more porous compared to the convcentional rice farming system, which usually has lower C organic content and use inorganic fertilizer. Furthermore, Mandal et al. (2003) reported that application of green manure (Sesbaniarostrata, Sesbania aculeata, and Vigna radiata) together with different rates of nitrogen fertilizer application increased the concentration of soil organic matter and total

166 Proceeding The International Seminar on Tropical Horticulture Horticulture for The Quality of Life Bogor, December 10th, 2018

nitrogen, improved total pore space, water stable aggregates, hydraulic conductivity, and reduced bulk density.

4. Conclusion From the data and discussion, it can be concluded that the soil chemical- physical fertility in organic field in Kopeng Village,Semarang Regency, was more superior than in conventional vegetables farming system including soil pH, C organic and N, P and K total, bulk density, particle density, soil porosity and permeability (slow and fast drainage).

References Alice J., Sujeetha R.P. and Venugopal M S. 2003. Effect of organic farming on management of rice brown plant hopper. IRRN. 28(2): 36 – 37 Amalia O. 2011. Soil quality under organic and conventional farming systems in West and Central Java, Indonesia. Master Dissertation. Interuniversity Programme in Physical Land Resources. Ghent University, Belgium. 62 p. Chino M., Hayashi M. and Fukumorita T. 1987. Chemical composition of rice phloem sap and its fluctuation. J. Plant Nutr 10: 1651-1661. Cho J.Y., Han K.W., Choi J.K., Kim Y.J. and Yoon K.S. 2002. N and P losses from paddy field plot in Central Korea. Soil Science and Plant Nutrition. 48: 301-306. Clark M.S., Horwath W.R., Shennan C. and Scow KM. 1998. Changes in soil chemical properties resulting from organic and low-input farming practices. Agronomy Journal. 90: 662-671. Doran J.W. and Parkin T.B. 1994. Defining and assessing soil quality. In: Defining soil quality for a sustainable environment. Eds. J.W Doran, D.C. Coleman, D.F. Bezdicek, B.A. Stewart. 3-21 p. Doran J.W. and Zeis M.R. 2000. Soil health and sustainability: managing the biotic component of soil quality. Applied Soil Ecology 15: 3-11 Hansen B., Kristensen E.S., Grant R., Hogh J.H., Simmelsgaard S.E. and Olesen J.E. 2000. Nitrogen leaching from conventional versus organic farming systems- a system modelling approach. European Journal of Agronomy. 13: 65–82. Haynes R.J. 2005. Labile organic matter fractions as central component of the quality of agricultural soil: an overview. Adv Agron 85: 221-268 Hasegawa H., Furukawa Y. and Kimura S.D. 2005. On-farm assessment of organic amendments effects on nutrient status and nutrient use efficiency of organic rice fields in Northern Japan. Agriculture, Ecosystems and Environment. 108: 350- 362. Herrick J.E. 2000. Soil Quality: An indicator of sustainable land management. Applied Soil Ecology 15: 75-83 Kajimura T., Fujisaki K. and Nagasuji F. 1995. Effect of organic rice farming on leafhoppers and plant hoppers and amino acid contents in rice phloem sap and survival rate of plant hoppers. Applied Entomology Journal. 30: 12–22.

Proceeding The International Seminar on Tropical Horticulture 167 Horticulture for The Quality of Life

Bogor, December 10th, 2018

Landa J.K, Pareek R.P. and Becker M. 1992. Stem-nodulating legume-Rhyzobium symbiosis and its agronomic use in lowland rice. Springer, New York(US). Mäder P., Fliessbach A., Dubois D., Gunst L., Fried P. and Niggli U. 2002. Soil fertility and biodiversity in organic farming. Science, 296, 1694-1697. Mandal, Uttam K., Singh G., Victor U.S. and Sharma K.L. 2003. Green Manuring: its effect on soil properties and crop growth under rice-wheat cropping system. European Journal of Agronomy. 19: 225-237 Oehl F., Sieverding E., Mäder P., Dubois D., Ineichen K., Boller T. and Wiemken A. 2004. Impact of long-term conventional and organic farming on the diversity of arbuscular mycorrhizal fungi. Oecologia. 138: 574-583. Pirngadi K. 2009. The contribution of organic matter on increasing rice yield to support sustainable agriculture and national food security. Journal of Agricultural Innovation Development. 2(1): 48-64. Prakhas Y.S., Bhadoria P.B.S. and Rakshit A. 2002. Relative efficacy of organic manure in improving milling and cooking quality of rice. IRRN. 27(1): 43–44. Rasmussen P.E. and Parton W.J. 1994. Long-term effects of residue management in wheat-fallow: inputs, yields, and soil organic matter. Soil Science Society of America Journal. 58: 523-530. Ray S.S. and Gupta R.P. 2001. Effect of green manuring and tillage practices on physical properties of puddled loam soil under rice-wheat cropping system. Journal of Indian Society Soil Science. 49(4): 670 – 678. Reganold J.P., Elliott L.F. and Unger Y.L., 1987. Long-term effects of organic and conventional farming on soil erosion. Nature 330: 370-372. Sharma K.L., Grace J.K., Mandal U.K., Gajbhiye P.N., Srinivas K., Korwar G.R., Bindu V.H., Ramesh V., Ramachandran K. and Yadav S.K. 2008. Evaluation of long- term soil management practices using key indicators and soil quality indices in a semi-arid tropical Alfisol. Australian Journal of Soil Research. 46: 368–377. Soil Research Institute. 2009. Penuntun analisa kimia tanah, tanaman, air dan pupuk (Procedure to measure soil chemical, plant, water and fertilizer). Soil Research Institute, Bogor. 234 p. (in Indonesian). Sommerfeldt T.G., Chang C. and Entz T. 1988. Long-term annual manure applications increase soil organic matter and nitrogen, and decrease carbon to nitrogen ratio. Soil Science Society of America Journal. 52: 1668-1672. Stolze M., Piorr A., Harring A. and Dabbert S. 2002. The environmental impact of organic farming in Europe. Organic farming in Europe: Economics and Policy. Vol 6. University of Hohenheim, Germany(DE). Sukristiyonubowo, Wiwik H., Sofyan A., Benito H.P. and De Neve S. 2011. Change from conventional to organic rice farming: Biophysical and Socioeconomic Reasons. Journal of Agricultural Science and Soil Science. 3(5): 172-182. USDA. 1999. Soil quality indicators: Physical, chemical and biological indicators for soil quality assessment and management. 2 p. Wander M.M., Traina S.J., Stinner B.R. and Peters S.E. 1994. Organic and conventional management effects on biologically active organic matter pools. Soil Science Society of America Journal. 58: 1130-1139.

168 Proceeding The International Seminar on Tropical Horticulture Horticulture for The Quality of Life Bogor, December 10th, 2018

Whitbread A.M., Blair G.J. and Lefroy R.D.B. 2000. Managing legume leys, residues and fertilisers to enhance the sustainability of wheat cropping system in Australia. 1. The effects on wheat yields and nutrient balance. Soil and Tillage Research. 54: 63–75. Yan D., Wang D. and Linzhang Y. 2007. Long term effect chemical fertiliser, straw and manure on labile organic matter in a paddy soil. Biol. Fertil. Soil Journal. 44: 93- 101.

Proceeding The International Seminar on Tropical Horticulture 169 Horticulture for The Quality of Life

Bogor, December 10th, 2018