Water footprint assessment of crop production: A comprehensive review

Abstract

The increasing global demand for food, coupled with rising water scarcity and climate variability, has made sustainable water management in agriculture a critical concern. Water Footprint Assessment (WFA) has emerged as a comprehensive tool to evaluate the direct and indirect freshwater use associated with crop production, offering insights into green, blue, and grey water components. This review synthesizes existing literature on WFA methodologies, applications across different spatial scales, and its relevance in evaluating water use efficiency and environmental sustainability in agriculture. The paper explores various models and approaches—including empirical, statistical, and hydrological methods—used to estimate crop water requirements and footprints. It highlights global, national, and regional case studies, with a focus on both developed and developing countries, and emphasizes the role of WFA in identifying water-intensive crops, pollution hotspots, and inefficiencies in irrigation practices. Special attention is given to the challenges of grey water footprint estimation and the implications of climate change on water availability and crop water use. The review also identifies key research gaps and future directions, advocating for integrated, data-driven strategies to enhance water productivity and support policy frameworks for sustainable agricultural water management. Overall, this paper underscores the importance of WFA as a decision-support tool for optimizing water use, reducing environmental impact, and ensuring food and water security.