Multisplit Nitrogen Application via Drip Irrigation Improves Maize Grain Yield and Nitrogen Use Efficiency

Abstract

Conventional fertilization with most N applied before or during early maize (Zea mays L.) growth stages can negatively affect production if soil N is insufficient after silking. Here, drip irrigation with a split application of N (drip fertigation) was evaluated to determine whether the effect on yield and N use efficiency (NUE) differs with cropping practice. Compared with conventional fertilization, drip fertigation increased yield by 13 and 14% at a low planting density under a low N rate (L) and by 15% at a high planting density under a high N rate (H) in 2012 and 2013, respectively. Yield increases under drip fertigation were attributed to 18 and 17% increases in postsilking dry matter (DM) accumulation under L, and 12 and 10% increases in presilking DM accumulation, and 17 and 16% increases in postsilking DM accumulation under H in 2012 and 2013, respectively. Increased postsilking N accumulation under drip fertigation, promoted by greater root length and soil mineral N after silking, maintained increased leaf area index (LAI) and DM accumulation rate to improve postsilking DM accumulation under L. Greater N accumulation under drip fertigation from the 12‐leaf stage to silking and after silking promoted greater LAI and DM accumulation rate to increase pre‐ and postsilking DM accumulation under H. Because of greater grain yield and N uptake and less water consumption, drip irrigation improved NUE and irrigation water use efficiency. Drip fertigation can effectively improving maize grain yield and NUE resulting from improved DM accumulation with increased early‐season N uptake.