有机氮替代无机氮对旱作全膜双垄沟播玉米产量和水氮利用效率的影响

为了促进黄土高原西部半干旱区水氮高效利用和农业的可持续性生产,探索适宜的有机氮替代无机氮水平,于2016—2018年在甘肃农业大学旱作农业综合实验站进行了3年的大田试验,设置了6个处理:单施化学氮肥不施有机肥(T₁)、有机肥50%替代化学氮肥(T₂)、有机肥37.5%替代化学氮肥(T₃)、有机肥25%替代化学氮肥(T₄)、有机肥12.5%替代化学氮肥(T₅)和不施氮肥对照(CK),研究了有机氮替代无机氮对全膜双垄沟播玉米种植系统产量、经济效益、水氮利用效率的影响.结果表明: 氮肥施用显著增加了玉米产量和水氮利用效率.在200 kg·hm^-2施氮水平下,有机肥氮替代处理在干旱年份表现出明显的增产增效作用;而在丰水年,有机氮替代无机氮处理籽粒产量、水氮利用效率与对照无显著差异.总体来说,与单施化肥相比,50%和37.5%替代处理籽粒产量分别增加15.6%和18.2%,收获指数分别增加35.1%和27.0%;水分利用效率、降水利用效率、氮肥农学利用效率和偏生产力分别增加17.4%、15.7%、15.6%、155.2%和22.3%、17.7%、18.0%、179.3%.表明在相等的总氮量投入下,50%和37.5%是该地区全膜双垄沟播玉米有机氮替代无机氮的适宜水平,建议在生产中推广应用.

Effects of the substitution of inorganic nitrogen by organic nitrogen fertilizer on maize grain yield and water and nitrogen use efficiency under plastic film fully mulched ridge-furrow in semi-arid area

To improve water and nitrogen (N) fertilizer use efficiency, increase sustainable agricultural production, and explore the appropriate substitution level of inorganic N fertilizer by organic fertilizer in the semi-arid region of the western Loess Plateau, a three-year field experiment was conducted at the Dingxi Agri-ecological Station in 2016-2018. We examined the effects of commercial organic fertilizer substitution on maize grain yield as well as the use efficiency of water and N fertilizer under plastic film fully mulched ridge-furrow in dryland. There were six fertilizer treatments: T₁, N fertilizer without organic fertilizer; T₂, substitution 50% inorganic-N with organic-N; T₃, substitution 37.5% inorganic-N with organic-N; T₄, substitution 25% inorganic-N with organic-N; T₅, substitution 12.5% inorganic-N with organic-N; and CK, no N fertilizer. The results showed that treatments of commercial organic fertilizer substitution (T₂-T₅) had higher grain yield and water and N efficiency than that in T₁ treatment in dry year under 200 kg N·hm^-2. The changes in grain yield and water and N fertilizer efficiency had no significant difference in treatments of commercial organic fertilizer substitution compared to T₁ treatment in wet year. T₂ and T₃ treatments increased grain yield by 15.6% and 18.2%, and with 35.1% and 27.0% enhancement in harvest index compared to T₁. T₂ and T₃ treatments increased water use efficiency, rainfall use efficiency, N agrono-mic efficiency and partial productivity of N fertilizer by 17.4% and 22.3%, 15.7% and 17.7%, 15.6% and 18.0%, 155.2% and 179.3%. These results demonstrated that under the same N input level, 50% and 37.5% substitution inorganic-N with organic-N could be a suitable substitution rate under plastic film fully mulched ridge-furrow, which could be recommended as a fertilizer application pattern in this area.