Optimizing planting management practices considering a suite of crop water footprint indicators —A case-study of the Fengjiashan Irrigation District

Irrational allocation of water resources, and excessive fertilization are the main problems facing the sustainable development of agriculture in China. Reducing agricultural water consumption and the impact of agricultural non-point source pollution are key to sustainable and healthy development for regional agriculture. The water footprint theory provides an important methodological tool for agricultural production and water resource management. However, most of the previous studies involve simple scenario comparison or assess the influence of individual factors on the crop water footprint. An integrated methodological and technological framework for optimizing planting structures and management strategies in irrigation districts, which simultaneously considers blue, green, and grey water footprints, has yet to be developed. Based on this, taking Fengjiashan Irrigation District (FID) as an example, the APEX model was introduced to estimate yield and evapotranspiration under different crop types, irrigation systems, fertilization conditions, and planting structures to quantify crop water footprints. Subsequently, an optimization model of plant structure and management practices based on water footprint was developed, which was solved by multi-objective particle swarm optimization. Finally, the optimization scheme of crop planting management with low-water-consumption and low-pollution in FID was identified. The results showed that 110 % of the irrigation quota and 75 % of current fertilization were the most suitable irrigation and fertilization strategy in FID. In the path of planting structure, it was necessary to reduce the area of multiple planting and increase the area of monocropping. Under the optimal planting management practices, the total blue, green, and grey water footprint of the irrigated district changed by −12.3 %, 9.2 %, and −18.3 %. After optimization, the net income of crop planting in the irrigated area increased by 4.7 %. • An optimization method for best crop management in FID considering water footprints • Proposed a low-water, low-pollution crop planting management scheme • Identified 110 % irrigation quota and 75 % fertilization as optimal for FID • Adjusted wheat, corn, and rapeseed planting areas by −12.7 %, −13.9 %, and + 78.5 %