Comprehensive evaluation of the water-energy-food nexus in the agricultural management of the Tarim River Basin, Northwest China

The water-energy-food nexus index in the agricultural management of the Tarim River Basin (TRB) is an important index that reflects agricultural inputs productivity. This study used the crop water requirement, energy equivalent, and agricultural water-energy-food nexus index (WEFNI) model to comprehensively evaluate the water and energy consumption, water and energy productivity, and the WEFNI of the main crops (rice, wheat, maize and cotton) in the TRB from 1990 to 2019. The results indicated that different crops had significant differences in water and energy consumption. The blue water requirements of wheat, maize, rice, and cotton were 3174.9 m3 ha−1 yr−1, 4271.8 m3 ha−1 yr−1, 7283.3 m3 ha−1 yr−1 and 8769.3 m3 ha−1 yr−1, respectively. Of these crops, wheat had the lowest blue water requirements and cotton had the highest. In addition, the planting area of the TRB increased by 105 × 104 ha during the study period, with cotton accounting for 45% of the total planting area. The expansion of the planting area led to a continuous improvement in cotton production income, leading to the highest energy economic productivity in cotton (0.065 $/MJ). However, the increase in total water and energy consumption, water and energy mass productivity in cotton were lower than in the other three crops (0.15 kg/m3 and 0.04 kg/MJ). The average WEFNI of rice, wheat, maize and cotton was 0.40, 0.45, 0.43 and 0.35, respectively. This demonstrated that wheat had the highest resources utilization productivity in agricultural inputs, while cotton had the lowest. These results can provide an important scientific basis for current and future agricultural management optimization.