Modelling crop yield, water consumption, and water use efficiency for sustainable agroecosystem management

Agroecosystems provide food, energy, and essential services, while accounting for 80% of the world's total water use. Producing more food with limited water resources or improving water use efficiency (WUE) is an urgent task, especially in arid and semi-arid areas with fragile ecosystems and severe water shortages. This study integrated crop type distribution, irrigation data, remote sensing imagery, and meteorological factors to simulate the crop yield, water consumption, and WUE in the Heihe River Basin of China during 2007-2012. We found that variations in water consumption had little impact on crop yield because the value far exceeded the actual water requirement. From 2007 to 2012, the water consumption of corn increased by 11.24%, while its yield decreased by 0.63%. In contrast, the water con-sumptions of wheat, oilseed rape, and other crops decreased by 15.45%, 10.32%, and 4.61%, while their yields increased by 2.41%, 8.91%, and 1.13%, respectively. Consequently, the WUE of corn decreased by 10.68%, while that of oilseed rape, wheat, barley, and other crops increased by 21.44%, 21.13%, 4.96%, and 6.02%, respectively. The expansion of the area planted with corn led to a 3.36% increase in the WUE of the basin. However, this agricultural development is clearly unsustainable because it increased agricultural water consumption and decreased the ecological and domestic water supply. On-demand irrigation is therefore necessary to reduce water wastage and improve WUE. This would have reduced agricultural water consumption in 2007 and 2012 by 32.58% and 30.13%, and the WUEs would have increased by 48.33% and 43.12%, respectively. Sustainable water-efficient management should comprehensively consider the economic benefits and environmental burdens in crop structure adjustment, irrigation practices, and field management. Additionally, a knowledge-exchange system among experts, resource managers, and farmers is crucial for improving WUE strategies for sustainable agroecosystem development. (C) 2019 Elsevier Ltd. All rights reserved.