Efficient water management is critical to sustainable crop production in arid and semi-arid southwestern United States. A study was designed to evaluate the variations in soil water content (SWC) and nitrogen (N) dynamics within the 0–100 cm soil profile and forage maize (Zea mays L.) and sorghum (Sorghum bicolor) yields in winter cover crop integrated crop rotations in a semi-arid environment using a Root Zone Water Quality Model (RZQWM2). The cover cropping treatments were no cover crop (NCC), a mixture of grasses, brassicas, and legumes (GBL), a mixture of grasses and brassicas (GB), and a mixture of grasses and legumes (GL) under maize and sorghum silage production. The root mean square error (RMSE), index of agreement (d), and Nash-Sutcliffe model efficiency coefficient (NSE) were used to evaluate the effectiveness and efficiency of the model. The observations and simulations showed that the soil water content was greater and soil temperature was lower under cover crops than under NCC. Simulated N mineralization in maize and sorghum with cover cropping was 41.1–44.2 % and 41.9–42.3 % greater than NCC. Also, the model simulated that cover crops improved the plant N uptake by 15.4–17.3 % in maize and 13.6–14.7 % in sorghum compared to NCC. Simulated aboveground biomass yields of maize and sorghum were 8.11–24.2 % and 5.68–21.3 % greater with cover crops than with NCC. Integrating cover crops in maize and sorghum silage production systems can conserve soil water and improve N uptake, increasing silage yield under semi-arid irrigated conditions in the southwestern United States.

中文翻译：

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模拟覆盖作物对美国西南部半干旱地区土壤水分和氮动态以及青贮饲料产量的影响


高效的水资源管理对于美国西南部干旱和半干旱地区的可持续作物生产至关重要。一项研究旨在评估 0-100 cm 土壤剖面和饲料玉米 （Zea mays L.） 和高粱 （Sorghum bicolor） 产量内土壤含水量 （SWC） 和氮 （N） 动态的变化使用根区水质模型 （RZQWM2） 在半干旱环境中综合作物轮作。在玉米和高粱青贮饲料生产下，覆盖作物处理为无覆盖作物 （NCC）、禾本科、芸苔属植物和豆类混合物 （GBL）、禾本科植物和芸苔属植物混合物 （GB） 以及禾本科植物和豆类混合 （GL）。均方根误差 （RMSE） 、一致性指数 （d） 和 Nash-Sutcliffe 模型效率系数 （NSE） 用于评估模型的有效性和效率。观察和模拟表明，覆盖作物下的土壤含水量高于 NCC，土壤温度低于 NCC。覆盖作物玉米和高粱的模拟氮矿化比 NCC 高 41.1-44.2% 和 41.9-42.3%。此外，该模型模拟，与 NCC 相比，覆盖作物将玉米的植物氮吸收提高了 15.4-17.3%，高粱的植物氮吸收提高了 13.6-14.7%。玉米和高粱的模拟地上生物量产量比 NCC 高 8.11-24.2% 和 5.68-21.3%。在美国西南部的半干旱灌溉条件下，将覆盖作物整合到玉米和高粱青贮饲料生产系统中可以保持土壤水分并改善氮吸收，从而提高青贮饲料产量。