Effects of Long Term Organic and Conventional Farming on Physical and Chemical Properties of Soil

Field experiment was conducted to compare the soil status of organic and conventional farming system under rice and wheat cropping system. Laboratory analysis was made on the soil samples collected from a longterm organic farm (SOF) at Department of Soil Science, Khalsa College, Amritsar and compared with the soil samples collected from different conventional fields (SCF) after the harvest of rice crop to investigate the effect of organic sources and chemical fertilizers. The results of the study revealed that soil physical properties viz., bulk density, particle density and porosity varied from 1.26 g/cm³ to 1.31g/cm³ (SO) and 1.35 g/cm³ to 1.44 g/cm³ (SC), 2.62 g/cm³ to 2.67 g/cm³ (SO) and 2.62 g/cm³ to 2.68 g/cm³ (SC) and 50.19 to 52.80 per cent (SO) and 45.48 to 48.49 per cent (SC), respectively. Soil pH showed slightly acidic to alkaline (6.75 to 7.34) range in organic soil samples while conventional soil samples showed alkaline range (7.98 to 8.28). The electrical conductivity (EC) of conventional farming system was significantly higher than organic farming system. The highest value (0.421dS/m) of EC was observed in conventional farming system field while lowest (0.391 dS/m) in organic field. Soil organic carbon (OC) content in surface soil ranged between 0.74 to 0.85 per cent and 0.26 to 0.35 per cent in organic and conventional farming systems, respectively. Similar trends were observed in soil status of available N, P and K under organic and conventional farming systems.