Assessment of Blue and Green Water Footprint of Rice Crop for Prayagraj Region

Abstract

The rising demand for water in agriculture, combined with increasing concerns over freshwater scarcity, necessitates the adoption of efficient water use assessment frameworks. The water footprint concept serves as a comprehensive indicator of water use by distinguishing between green water (rainwater) and blue water (irrigation water) components. This study evaluates the green and blue water footprints associated with rice cultivation in the Prayagraj region of Uttar Pradesh, India—a key kharif season crop characterized by high water demand. Utilizing climatic data, soil characteristics, and crop parameters, the CROPWAT 8.0 model was applied to determine crop water requirements, effective rainfall, and irrigation demand. The analysis revealed that the total water footprint of rice ranged from 2332.05 to 4931.14 m³/ton, with green water accounting for 1208.97 to 2724.19 m³/ton and blue water for 697.98 to 3100.39 m³/ton over the study period. On average, green water contributed approximately 71%, while blue water contributed around 29% to the total water footprint, underscoring the region’s dependence on monsoonal rainfall during the cropping season. Nevertheless, the considerable blue water contribution highlights the critical role of supplemental irrigation during dry spells and sensitive crop growth stages. These findings emphasize the need to integrate water footprint metrics into agricultural planning and water resource management to enhance sustainability and ensure resilient rice production under variable climatic conditions.