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

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

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