Abstract In tropical agriculture, maize (Zea mays L.) intercropped with palisadegrass (Brachiaria brizantha cv. Marandu) is considered a highly relevant cropping system to deliver both residue and forage. However, the benefits of inclusion of palisadegrass in maize systems and its influence on fertilizer dynamics and nitrogen (N) budget as well as the period after maize harvest for which palisadegrass continues to grow remain unclear. Thus, we conducted field studies to determine crop growth, end-season biomass, N fertilizer recovery, and overall N budget between an intercrop and a monoculture at two different sites during conventional and late-planted maize seasons. The cropping systems evaluated were maize and palisadegrass in monocultures and two intercrop patterns, serving as cover crop or forage with simulated grazing. From planting to grain harvest, intercrop patterns did not affect grain yield, final N content, and N fertilizer dynamics. Post-harvest, palisadegrass from intercrop patterns improved biomass from 1 to 10 Mg ha−1 and N content from 8 to 300 kg ha−1, relative to fallow after maize monoculture. Contribution of palisadegrass intercropping on N fertilizer recovery was low at approximately 4.5 kg ha-1 when both the crops were growing simultaneously and approximately 2.4 kg ha−1 following maize grain harvest. In three out of four sites over 2 years, intercrop patterns did not affect total N fertilizer recovery compared with their monocultures, averaging at approximately 51 %. Advantages of maize-palisadegrass intercropping on biomass, yield, and N cycling were documented at the site where maize was planted during the conventional season, despite the yearly variation in weather conditions. A negative N budget of −230 kg ha−1 was estimated when grazing was simulated during the conventional maize planting season, suggesting greater N requirements of the intercropped palisadegrass when serving as forage.

中文翻译：

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关闭间作玉米和栅栏的氮收支

摘要 在热带农业中，玉米 (Zea mays L.) 与栅栏草 (Brachiaria brizantha cv. Marandu) 间作被认为是一种高度相关的种植系统，可提供残留物和草料。然而，在玉米系统中加入栅栏的好处及其对肥料动态和氮 (N) 预算的影响以及在玉米收获后栅栏继续生长的时期仍不清楚。因此，我们进行了田间研究，以确定在常规和晚播玉米季节期间，在两个不同地点间作和单一栽培之间的作物生长、季末生物量、氮肥回收率和总体氮收支。评估的种植系统是单一栽培中的玉米和栅栏草以及两种间作模式，用作覆盖作物或模拟放牧的草料。从种植到谷物收获，间作模式不影响谷物产量、最终氮含量和氮肥动态。收获后，间作模式的栅栏草将生物量从 1 Mg ha-1 提高到 10 Mg ha-1，氮含量从 8 到 300 kg ha-1，相对于玉米单一栽培后的休耕。当两种作物同时生长时，栅栏间作对氮肥回收的贡献较低，约为 4.5 kg ha-1，玉米收获后约为 2.4 kg ha-1。在超过 2 年的四个地点中，三个地点的间作模式与其单一栽培相比不影响总氮肥回收率，平均约为 51%。在常规季节种植玉米的地点记录了玉米-栅栏间作在生物量、产量和氮循环方面的优势，尽管天气条件每年都在变化。在常规玉米种植季节模拟放牧时，估计负氮预算为 -230 kg ha-1，这表明间作栅栏草用作牧草时需要更多的氮。