Spatial variability studies of soil hydro-physical properties using GIS for sustainable crop planning of a watershed of eastern India and its testing in a rainfed rice area

In this study soil hydro-physical properties such as soil texture, available water capacity, and organic carbon, along with existing land use and topography of a representative watershed of eastern India (Kadalipal watershed, 20.80–20.86°N and 85.54–86.50°E, Dhenkanal district, Orissa), were spatially mapped after collecting data from different sources (ground-truthing, profile survey, remote sensing satellite imagery). Since availability of water is confined to the south-west monsoon period (rainy season, June–September), eastern India is mainly mono-cropped, dominated by rice but second crops can be planned based on the soil hydro-physical properties, mainly water retention and available water of the soil profile utilising residual soil moisture. Keeping the existing land use as a base and considering the potential and prospects of soil hydro-physical properties in different topographies, in this investigation, an alternative land-use plan was developed in different parts of the watershed and tested in its rainfed rice area. Since direct measurement of available water capacity or soil water constants over a large area is time-consuming, pedo-transfer functions were also developed to predict soil water constants using easily measured parameters (e.g. cation exchange capacity, organic carbon, oven-dry bulk density, soil texture, calcium carbonate, etc.) of arable land of the watershed. Results of implementation revealed that the new cropping system was practical for increasing production, productivity, profitability, and sustainability of the rainfed rice area of the eastern India.