Nitrogen fertilizer management effects on soil nitrate leaching, grain yield and economic benefit of summer maize in Northwest China

Reducing soil nitrate leaching losses from agricultural ecosystem and improving crop yield and nitrogen use efficiency with effective nitrogen management strategies are extremely important for sustainable agricultural development. A-two-year field experiment was conducted to investigate the effects of five nitrogen management strategies (CK: no nitrogen application; FP: applying 210 kg N ha−1 at sowing; MFP: applying 105 kg N ha−1 at sowing and top-dressing 105 kg N ha−1 at V12 stage; Drip210 and Drip150: multi-split-N fertigation (MSF, sowing: 20%, V6: 30%, V14: 30% and R1: 20%) with 210 and 150 kg N ha−1) on soil nitrate-N (NO3−-N) distribution and residual, nitrate leaching losses, nitrogen use efficiency (NUE), grain yield and economic benefit of summer maize in Northwest China. The results showed that MSF produced more consistent soil NO3−-N content over the entire maize growing season. The two-year average leachate NO3−-N concentration of Drip210 and Drip150 was 24.1 and 19.2 mg L−1, significantly lower than FP and MFP. The total nitrate leaching losses (TNLL) of Drip210 and Drip150 were significantly lower than that of FP and MFP (P < 0.05). The two-year average TNLL of Drip210 and Drip150 was 19.0 and 14.4 kg ha−1, decreased by 32.4% and 48.7% compared with FP (28.1 kg ha−1), respectively. The above-ground biomass, grain yield and NUE of Drip210 and Drip150 were higher than that of FP and MFP (P < 0.05). Both Drip210 and Drip150 achieved comparable grain yield, but Drip150 used 28.6% less nitrogen than Drip210, resulted in 24.0% lower TNLL and higher NUE than Drip210. In addition, the average economic benefit under Drip150 was the highest and increased by 397 and 1675 CNY ha−1, respectively, compared with Drip210 and MFP. Therefore, Drip150 was recommended as a promising fertilization strategy to reduce nitrate leaching losses and improve nitrogen use efficiency, while maintain high crop yield and economic benefit in Northwest China.