氮肥减施对夏玉米生长及水氮利用效率的影响

为探索夏玉米减氮增效科学生产模式，研究滴灌水肥一体化条件下氮肥减施对夏玉米形态生长指标、子粒产量、水氮利用效率及土壤硝态氮残留量的影响。以传统畦灌施氮模式(CK，施氮量300 kg/hm²)为对照，滴灌水肥一体化处理依据0～20 cm土层含水率进行补灌，设4个施氮水平(DN120:120 kg/hm²、DN180:180 kg/hm²、DN240:240kg/hm²、DN300:300 kg/hm²)。结果表明，滴灌条件下各处理夏玉米生育期灌水量差异不大，滴灌水肥一体化夏玉米的株高、叶面积指数和地上部干质量随施氮量增加均呈增大趋势，当施氮量超过180 kg/hm²时，处理间各项指标差异不显著。随着氮肥用量的增多，滴灌夏玉米子粒产量和土壤硝态氮残留量逐渐增大，水分利用效率(WUE)呈先增大后减小趋势，氮肥偏生产力(NPFP)逐渐降低。与CK和DN300处理相比，DN180处理玉米子粒产量无显著差异，施氮量减少40%，耗水量减少10.10%～19.99%,WU...

Effects of Nitrogen Reduction on Growth and Water-Nitrogen Use Efficiency of Summer Maize

To explore the scientific production mode of reducing nitrogen and increasing efficiency of summer maize, the effects of nitrogen reduction on growth indexes, grain yield, water-nitrogen use efficiency and residual nitrate nitrogen of summer maize under drip irrigation were studied. The experiment takes traditional border irrigation and nitrogen application mode(CK; nitrogen rate:300 kg/ha) as the control; the drip irrigation treatments were based on 0-20 cm soil moisture content for supplementary irrigation, and four nitrogen levels(DN₁₂₀:120 kg/ha, DN₁₈₀:180 kg/ha, DN₂₄₀:240 kg/ha DN₃₀₀:300 kg/ha) were set. The results showed that the irrigation amount of summer maize under drip irrigation increased with the increase of nitrogen application, but the difference was not significant. The plant height, leaf area index, and aboveground biomass under drip irrigation increased with the increase of nitrogen rate, but there was no significant difference when nitrogen rate exceeded 180 kg/ha. With the increase of nitrogen application rate, grain yield and residual nitrate nitrogen of summer maize under drip irrigation increased, water use efficiency(WUE) increased first and then decreased, and nitrogen partial factor productivity(NPFP) decreased gradually. Compared with CK and DN₃₀₀ treatments, DN₁₈₀ treatment had no significant difference in grain yield, but the amount of nitrogen application, ET and residual nitrate nitrogen decreased by 40%, 10.10%-19.99% and 17.51%-47.71%, respectively.