Study on the Agricultural Grey Water Footprint and Efficiency in Henan Province: A Spatiotemporal Analysis

The managing agricultural water pollution is crucial for mitigating the water crisis and fostering sustainable regional development. Therefore, it is essential to understand the spatiotemporal characteristics of agricultural Grey Water Footprint (GWF) and its efficiency to formulate tailored regional management strategies. Building on this, the study first calculated the agricultural GWF and efficiency for 18 prefecture-level cities in Henan Province from 2001 to 2021, and then analyzed their spatiotemporal patterns using ArcGIS software. The findings reveal: (1) In Henan Province, the majority of agricultural grey water footprint stems from crop cultivation, particularly from phosphorus fertilizers. Over time, the agricultural grey water footprint in Henan Province initially increased and then decreased, with the southern areas generally exhibiting a higher footprint compared to the north. (2) Prior to 2012, the efficiency of agricultural grey water footprint in Henan Province remained relatively stable, but has since seen a sharp rise, with the central region consistently demonstrating higher efficiency. These results offer critical decision-making insights for managing agricultural water pollution and guiding industry rest.