Pedotransfer functions: a tool for estimating hydraulic properties of two major soil types of India

In recent years, georeferenced soil information system has gained significance in agricultural land-use planning and monitoring the changes in soil properties/soil quality induced by land-use changes. The spatio-temporal information on saturated hydraulic conductivity (sHC) and soil water retention-release behaviour is essential for proper crop and land-use planning. The sHC greatly influences the drainage process and soil water retention-release behaviour, ultimately affecting the crop growth and yield. However, sHC and water retention are not measured in a routine soil survey and are generally estimated from easily measurable soil parameters through pedotransfer functions (PTFs). In the present study, PTFs for sHC and water retention were developed separately for the soils of two food-growing zones of India (the Indo-Gangetic Plains (IGP) and the black soil region (BSR)). For the IGP soils, sHC is affected by the increased subsoil bulk density due to intensive cultivation. In BSR, presence of Na+ and Mg++ ions affects the drainage and water retention of the soils. Therefore, these soil parameters were considered while developing the PTFs using stepwise regression technique in SPSS. The validation of PTFs was found to be satisfactory with low RMSE values and high model efficiency.