Corn (Zea mays L.)–soybean [Glycine max (L.) Merr.] is among the most typical crop rotations in the U.S. Corn Belt, and N is the most limiting nutrient for both crops. This study aims to assess the effects of N management for corn on the following soybean crop. Two corn–soybean rotation N fertilizer rate studies—a long-term study (1983–2020, Case Study I) and a two-season study (2019–2020, Case Study II)—were conducted in Kansas (United States). Case Study I focused on soybean seed yield as the response variable, whereas Case Study II included a detailed seasonal characterization of soil N, symbiotic N fixation (SNF), and plant N uptake for soybean considering N fertilizer rates on the previous corn crop. Apparent N budgets from corn (N fertilizer minus grain N removal) ranged from approximately −100 to approximately +50 kg N ha⁻¹, and soybean yields were slightly or not affected by corn N management. Case Study I showed that long-term N budgets in corn crops did not affect the following soybean crop yields. In Case Study II, the previous corn N management produced negative or small N surplus that influenced neither soil residual N nor SNF, without compromising soybean productivity. Farmers applying close to economic optimum N rates on corn will likely not generate scenarios of N surplus to compromise SNF or soybean yields. Forthcoming research should further address how long-term and large soil N mining or surplus in corn may enhance or inhibit N fixation for the next soybean crop.

中文翻译：

---

玉米氮管理对以下大豆作物的影响

玉米 ( Zea mays L.)–大豆 [ Glycine max(L.) Merr.] 是美国玉米带最典型的作物轮作之一，N 是两种作物最受限制的养分。本研究旨在评估玉米氮肥管理对后续大豆作物的影响。在堪萨斯州（美国）进行了两项玉米-大豆轮作氮肥施用量研究——一项长期研究（1983-2020 年，案例研究 I）和一项两季研究（2019-2020 年，案例研究 II）。案例研究 I 侧重于将大豆种子产量作为响应变量，而案例研究 II 包括土壤 N、共生 N 固定 (SNF) 和大豆植物 N 吸收的详细季节性特征，考虑到前一玉米作物的 N 施肥率。来自玉米的表观 N 预算（N 肥料减去谷物 N 去除）范围从大约 -100 到大约 +50 kg N ha ^-1, 大豆产量受到玉米氮管理的轻微影响或没有影响。案例研究 I 表明，玉米作物的长期氮预算不会影响随后的大豆作物产量。在案例研究 II 中，之前的玉米 N 管理产生了负的或少量的 N 过剩，既不影响土壤残留 N 也不影响 SNF，而不会影响大豆生产力。农民在玉米上应用接​​近经济的最佳氮肥用量可能不会产生氮过剩的情景，从而损害 SNF 或大豆产量。即将进行的研究应进一步解决长期和大面积土壤氮开采或玉米过剩如何增强或抑制下一个大豆作物的氮固定。