Effect of land use on the nature of soil acidity and lime requirement in terai soils of West Bengal.

摘要

Land use and related management practices are believed to influence soil properties and therefore soil processes. Terai region of West Bengal has diverse land use patterns like net sown, forest, plantation crops and fallow. The effect of these land uses on physicochemical properties and nature of soil acidity vis-a-vis lime requirement was studied in terai soils of West Bengal, India. Different forms of soil acidities: total acidity, total potential acidity, pH-dependent acidity, hydrolytic acidity, non-exchangeable acidity and exchangeable acidity ranged from 4.4 to 17.88, 3.36 to 16.80, 3.12 to 15.38, 4.16 to 16.76, 0.002 to 0.860 and 0.24 to 1.31 cm ol(p+) kg-1. Acidity values were the highest in tea soils followed by forest, cultivated and fallow soils. The average contributions of pH-dependent and hydrolytic acidities towards total potential and total acidities were 92.6 and 94.05%, respectively. The contribution of exchangeable acidity to total potential acidity was meagre (7.2%). All the forms of acidities showed significant positive correlation with exchangeable Al, extractable Al, oxalate bound Al, free Al2O3, free Fe2O3 and Al saturation of ECEC, and significant negative correlation with soil pH. Organic carbon was negatively correlated only to total potential and pH-dependent acidities. All the forms of acidities were significantly correlated to each other and to lime requirement. Lime requirement varied with the nature of soil acidity and was highest for tea soils followed by forest, cultivated and soils under fallow..