Prediction of Water Storage Capacity of Major Soil Groups of Eastern India

Profile water storage capacity of dominating soil groups of eastern region was determined. Out of 26 soil sub-groups, 9 had very high, 7 had high to very high, 3 had high, 3 had medium to high, 2 had medium and 1 each had low to medium and low water storage capacity. The highest profile water storage capacity of 27.8 to 28.4 cm m⁻¹ depth was found in Typic Ustochrept and the lowest of 8.9 to 9.8 cm m⁻¹ depth was found in Typic Ustipsamment. Out of 10 soil sub-groups in Inceptisols, 1 had low to medium, 1 had medium to high, 1 had high, 2 had high to very high and 5 had very high water storage capacity. Out of 8 soil sub-groups in Alfisols, 1 had very high, 2 had high to very high, 1 had high, 2 had medium to high and 2 had medium water storage capacity. In Entisols, very high profile water storage capacity varying from 20.5 to 26.9 cm/m depth, was observed in Lithic Ustorthent and Aeric Fluvaquent. The storage capacity was high to very high in Typic Ustorthent and low in Typic Ustipsamment. In Vertisols, very high profile water storage capacity was observed in Typic Haplustert and high to very high in Typic Chromustert, and high in Chromic Haplustert. In Mollisols, the profile water storage capacity was high to very high, varying from 16.1 to 27.8 cm m⁻¹ depth. Moisture retention at field capacity, wilting point and available water in these soils was influenced by two sets of factors, one set influencing positively while the other negatively. While silt, clay, organic carbon, calcium carbonate and cation exchange capacity influenced water storage positively, sand and bulk density had negative influence. Regression analysis was done to develop equations for predicting water retention at field capacity and wilting point, using soil parameters, viz. sand, silt, clay, bulk density, electrical conductivity, organic carbon, calcium carbonate and cation exchange capacity. Better prediction of available water was made through prediction of field capacity and wilting point instead of direct prediction of available water in soils.