Optimizing irrigation amount and fertilization rate of drip-fertigated spring maize in northwest China based on multi-level fuzzy comprehensive evaluation model

Abstract

The arid and semi-arid region of northwest China is an important region for spring maize production in China, but improper water and fertilizer management has caused ecological problems in these regions. A two-year field experiment was conducted in 2015 and 2016 in the Gansu Province of China to investigate the effects of different irrigation amounts and fertilization rates on growth, grain yield, water and fertilizer use efficiency, and soil nutrient residue of drip-fertigated spring maize, and explore the optimal combination of irrigation amount and fertilization rate based on a multi-level fuzzy comprehensive evaluation (MFCE) model. The irrigation levels included I60 (60% of crop evapotranspiration), I75, I90 and I105 in 2015 and I60, I80, I100 and I120 in 2016. The N-P2O5-K2O fertilization rates (kg ha−1) were F60–30–30, F120–60–60, F180–90–90 and F240–120–120. The results showed that plant height, stem diameter and leaf area index were highest under F240–120–120. Maize yield, dry matter, water use efficiency (WUE) followed a upward opening parabola with irrigation amount and fertilization rate, and reached the maximum under I90F180–90–90 in 2015 and under I100F180–90–90 in 2016. With the simultaneous increase in irrigation amount and fertilization rate, nitrate nitrogen content in the 60–120 cm soil layer showed an increasing trend. Based on the MFCE model, the irrigation amount of 415–450 mm combined with the N-P2O5-K2O rate of 144–77–77 to 180–90–90 kg ha−1 obtained the optimal comprehensive benefit of maize growth, economic return, water and fertilizer utilization and environmental benefit. This work can provide a scientific basis for the optimization and management of spring maize irrigation and fertilization in northwest China.