Improving maize production and decreasing nitrogen residue in soil using mulched drip fertigation

Nitrogen (N) application is important for agricultural practical management. The study aimed to determine the impact of N application amount on maize growth, water and N use efficiency, and soil N residue under in-season mulched drip fertigation (M-DF) in semi-arid region with chilling damage. The experiment was carried out in 2015 and 2016 in northeast China, with six N application amounts including 0, 140, 190, 240, 290 and 340 kg?ha? 1 (referred to N0, N140, N190, N240, N290 and N340). The N application amount of 340 kg?ha?1 is widely applied in local high-yield maize field. Results showed that appropriate application of N fertilizer under M-DF improved maize plant height, stem diameter, and leaf area index to respond positively to grain yield. In-season supply of N through M-DF increased the N accumulation (NA) of plant during maize reproductive stages (from tasseling to maturity), which accounted for 42.7?50.7% of the total NA for the whole growing season across the treatments. The effect of N application amount on the NA of plant was gradually more obvious after maize tasseling, which was mainly reflected in the differences in NA of ears. The NA of ears accounted for 75.3?77.7% of the total NA of plant at maturity across the treatments. The NA and N recovery efficiency of plant, grain yield, and water use efficiency at maturity obviously increased when the N rate ranged from 0 to 240 kg?ha?1; while it showed a negative effect when the N amount continue to increase. The soil N residue rate in treatments of N290 and N340 were much higher than other treatments, and obviously increased by 10.0?11.8% points the second year. The study suggested a reasonable threshold of 226?253 kg?ha?1 of N applied through in-season M-DF for maize with high yield and resources use efficiency but lower soil N residue rate, which decreased by 12.2?16.0% points compared with that under conventional N application amount of 340 kg?ha?1 in local field. The conclusions can provide scientific basis for maize production in northeast China and other regions with similar climate or productive conditions worldwide.