Water resource efficiency evaluation of crop production in arid and semi-arid regions based on water footprint and comparative advantage

Revealing the characteristics of crop water use in arid and semi-arid areas and clarifying the differences in crop species and water use between provinces will help propose measures to promote sustainable agricultural development from the perspective of efficient crop water use, which is crucial for ensuring global food security. In this study, taking arid and semi-arid Northwest China as an example, the temporal and spatial evolution characteristics of the water footprint (WF) of major grain and economic crops were systematically analyzed using WF and comparative advantage theory and the differences in WF among different regions and crops were evaluated. The results showed that from 2000 to 2020, the WF of regional agricultural production decreased significantly (p<0.01). The blue WF of grain and cash crops decreased from 59.9 % and 48.0 % in 2000-54.0 % and 41.2 % in 2020, respectively. The WF of wheat, rice, soybeans, maize, potatoes, vegetables, cotton, oil and fruits decreased by 40.9 %, 46.3 %, 50.1 %, 43.4 %, 48.9 %, 40.7 %, 40.6 %, 50.1 %, and 39.7 % from 2000 to 2020, respectively. The WF of grain crop production in Inner Mongolia was 45.8 % lower than that in Qinghai. The WF of economic crop production in Gansu was 2.7 times that of Ningxia. The differences in WF of crop production among regions led to different comparative advantages for different crops in different regions. Shanxi, Shaanxi and Inner Mongolia had comparative advantages in wheat production WF, with indices of 0.91, 0.90 and 0.89, respectively. The regions with relative comparative advantage of maize were Inner Mongolia, Shaanxi and Qinghai. The research results can provide a reference for the systematic analysis of crop production characteristics in other arid and semi-arid regions around the world and propose remedial measures for inter-regional crop production differences to contribute to a reduction in the number of people experiencing hunger.