Spatio-temporal evolution and driving factors of provincial grain crop water footprint in China from 2000 to 2023

With increasing water resource constraints and the growing demand for food security, accurately quantifying the water footprint of grain production and understanding its spatiotemporal evolution is of paramount importance. This study quantifies the spatiotemporal evolution of water footprints for major grain crops at the provincial level in China from 2000 to 2023 based on water footprint theory. Spatial autocorrelation models and the Logarithmic Mean Divisia Index (LMDI) model were employed to analyze the spatial distribution characteristics of water footprints and their driving factors. The findings indicate the following: (1) The water footprint of grain crops exhibits an upward trend, with a significant increase in the blue water footprint, averaging approximately 8414.71 × 10 8 m 3 annually. High water footprints persist in North, East, and Central China, while the Southwest and Northwest regions exhibit lower water footprints due to natural conditions, crop structure, and the implementation of water-saving measures; (2) Structurally, green, blue, and grey water account for 45%, 41%, and 14%, respectively. Additionally, the water footprint follows a “stable major crops with regional differentiation” pattern, with rice continuing to dominate and the proportion of corn steadily rising; (3) Spatially, the total water footprint shows significant positive spatial correlation, with clustering effects intensifying over time; (4) Production technology and irrigation management are key factors in suppressing the growth of water footprints, while water-saving measures show significant effects only during periods of strong policy enforcement. This study provides a scientific basis for region-specific agricultural water resource management.