Physicochemical Properties of Long-term Rice-fallow Cultivation and Uncultivated Soils of Nalbari, Assam, India

We aimed to assess the changes in physical and chemical properties of soils due to long-term continuous cultivation of rice under a rice –fallow system and that was compared with adjacent uncultivated soils. Soil samples were collected from respective sites and some soil physical (bulk density; BD, water holding capacity; WHC, and moisture content; MC) and chemical properties (pH, electrical conductivity; EC, organic carbon; OC, available N, available P, available K, exchangeable Ca, exchangeable Mg, available S, available Zn and available B) analyzed were evaluated using descriptive statistics. The results indicated that the soils under cultivation with rice- fallow were significantly (P<0.05) higher in BD (1.40 Mg m-3) and lower in WHC (41.34%) than the adjacent uncultivated soils (BD=1.34 Mg m-3 & WHC=42.26%). Soil’s chemical properties were significantly (P<0.05) lower in cultivated rice-fallow soils than the uncultivated soils (pH=5.51 and 5.93, OC=0.63 and 0.89%, available N=245.56 and 418.37 kg ha-1, available P= 31.27 and 42.62 kg ha-1, available K=120.98 and 145.90 kg ha-1, exchangeable Ca=5.35 and 5.93 C mol (p+) kg-1, available S=53.42 and 61.14 kg ha-1, available Zn=0.31 and 0.39 mg kg-1 and available B=0.41 and 0.48 mg kg-1) respectively. Continuous cultivation of crops without adopting proper management practices leads to decline in soil physical and chemical properties and proper management practices have to be adopted to sustain the properties of soil and crop productivity.