Silage maize (Zea mays L.) is a prominent forage crop in arid regions where water scarcity and the need for optimized nitrogen (N) fertilizer use pose significant challenges to agricultural productivity and sustainability. Interseeding leguminous cover crops with silage maize can enhance sustainable soil development and improve N management through biological N fixation. However, the competition interactions between silage maize and cover crops under constrained water-N conditions remains uncertain. This study conducted a three-year field experiment of interseeding leguminous cover crops with silage maize under varying drip fertigation conditions. The treatments included three types of leguminous cover crops-red clover (TP, Trifolium pretense L.), common vetch (VS, Vicia sativa L.), and hairy vetch (VV, Vicia villosa Roth)-combined with two N application rates (N1: 120 kg N ha−1 and N2: 180 kg N ha−1 and two irrigation levels (W1: 75 % of ETc and W2: 100 % ETc). The results showed that interseeding did not significantly inhabit plant height, stem diameter, and relative leaf chlorophyll content of silage maize compared to no covers (P>0.05). Under identical water and N conditions, the hay yield of maize interseeded with VV was significantly higher by 15.3 %-21.9 % compared to no covers (P<0.05), and the hay yield of the interseeding system vetch was significantly higher by 22.7 %-28.4 % (P<0.05). Specifically, under VV, W2N1 decreased actual evapotranspiration (ETa) by 2.1 %-12.9 % (P >0.05), and increased water use efficiency (WUE) by 8.6 %-12.5 % (P>0.05) and nitrogen partial factor productivity (PFPN) by 24.1 %-43.3 % (P<0.05) compared to W2N2. Dry matter of cover crops, which contributed to the increases in PFPN and WUE, ranged from 0.8 to1.2 Mg ha−1. Structural equation modeling indicated that the N application was the most important influencing the interseeding system. In conclusion, a 100 % ETc irrigation amount and a 120 kg N ha−1 N application rate in a silage maize-hairy vetch interseeding system can effectively increase forage yield and enhance water and N utilization efficiencies in the arid region.

中文翻译：

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在干旱地区，间种豆科覆盖作物会抑制青贮玉米的生长并降低水氮利用效率吗？


青贮玉米 （Zea mays L.） 是干旱地区的重要饲料作物，那里缺水和优化氮 （N） 肥料的使用对农业生产力和可持续性构成了重大挑战。豆科覆盖作物与青贮玉米间种可以通过生物固氮来促进土壤的可持续发展并改善氮管理。然而，在受水氮限制的条件下，青贮玉米和覆盖作物之间的竞争相互作用仍然不确定。本研究进行了一项为期三年的田间试验，在不同的滴灌施肥条件下将豆科覆盖作物与青贮玉米进行间种。处理包括三种类型的豆科覆盖作物 - 红三叶草 （TP， Trifolium pretense L.）、紫云英 （VS， Vicia sativa L.） 和毛豌云英 （VV， Vicia villosa Roth） - 结合两种氮肥施用量 （N1： 120 kg N ha-1 和 N2： 180 kg N ha-1 和两个灌溉水平 （W1： 75 % ETc 和 W2： 100 % ETc）。结果表明，与无覆盖相比，间播对青贮玉米的株高、茎粗和相对叶绿素含量没有显著影响（P>0.05）。在水氮相同条件下，紫云英混种玉米干草产量显著高于无覆盖玉米15.3 %—21.9 %（P<0.05），紫云英间播系统紫云英干草产量显著提高22.7 %—28.4 %（P<0.05）。具体而言，在 VV 下，与 W2N2 相比，W2N1 降低了 2.1 %-12.9 % 的实际蒸散量 （ETa） （P >0.05），水分利用效率 （WUE） 提高了 8.6 %-12.5 % （P>0.05），氮部分因子生产力 （PFPN） 提高了 24.1 %-43.3 % （P<0.05）。导致 PFPN 和 WUE 增加的覆盖作物的干物质范围为 0.8 至 1.2 Mg ha-1。 结构方程模型表明，施氮是影响间种系统的最重要因素。总之，在青贮玉米-毛豌紫云英间播系统中，100 % ETc 灌溉量和 120 kg N ha−1 N 施用量可以有效提高干旱地区牧草产量并提高水和氮利用效率。