The book titled "Sustainable Crop Planning in Rice-Fallow Area: An Agro-Hydrological and Geospatial Technology Based Approach" presents a scientific and practical method to utilise large tracts of land that remain fallow after the harvesting of kharif rice for rabi crop cultivation. This book describes the use of the agro-hydrological model SWAT and geospatial technology to delineate rice-fallow areas and assess the availability of residual soil moisture, in-situ groundwater and surface water resources for supporting second cropping in the Kantamal Catchment of the Mahanadi River Basin of India. It further uses spatial crop modelling to estimate the yield potential of various rabi crops under both residual soil moisture and supplemental irrigation conditions. This book provides a replicable framework for promoting second cropping in rainfed areas by identifying potential zones and recommending scientific interventions for sustainable crop planning. The approach can be adopted across different river basins to enhance land use efficiency, crop productivity and increase farmers' income, thereby contributing to national food security and the livelihood development of rural communities.