Crop residue amendment to soil is recommended as an effective management practice to return nutrients, especially in the maize-soybean rotation system where large amounts of maize residues are produced. Quantifying the utilisation of maize-residue N by the subsequent soybean crop is essential for optimising the N fertilisation strategy for sustainable production. However, whether and how maize residue amendment alters N acquisition in soybean plants are largely unknown. It was hypothesised that maize residue would supply N and enhance N₂ fixation to meet the N requirements of subsequent soybeans. Three treatments, namely: 1) chemical fertiliser (55.2, 35.2 and 22.4 kg ha⁻¹ of N, P and K, respectively), 2) maize residue (8 t ha⁻¹), and 3) non-fertiliser were applied in a maize-soybean rotation system in a Mollisol soil. It was demonstrated that soybean seed yield in the maize-residue treatment was the same as that in the chemical fertiliser treatment, with 2.9 vs. 3.2 t ha⁻¹ in 2014, 2.7 vs. 2.6 t ha⁻¹ in 2016, and 3.0 vs. 3.1 t ha⁻¹ in 2018. A follow-up pot experiment using ¹⁵N-labelled residue indicated that the residue-derived N accounted for 0.5 % of the total N in soybean seeds and the proportion of symbiotically fixed N reached 82 %. The amount of fixed N during the pod-filling period in the residue treatment was 0.66 g plant^-1, which was 49 % and 41 % higher than those in the chemical fertiliser and non-fertiliser treatments, respectively. The stimulation of N₂ fixation was associated with an increase in fixed N per nodule and the enrichment of diazotrophs in the rhizosphere of soybean. With maize residue amendment, the increased N₂-fixing capability of nodules during the reproductive period, rather than residue-derived N, fulfilled the N demand for maintaining seed yield of soybean. In the maize-soybean rotation system, maize residue amendment would facilitate the N₂ fixation to partly substitute for N fertiliser for soybean production in Mollisols.

建议对土壤进行作物残留改良作为一种有效的管理措施，以恢复养分，特别是在产生大量玉米残留的玉米-大豆轮作系统中。量化后续大豆作物对玉米残留氮的利用对于优化可持续生产的施氮策略至关重要。然而，玉米残留改良剂是否以及如何改变大豆植物中氮的获取在很大程度上是未知的。假设玉米渣将供应N 并增强N ₂固定以满足后续大豆的N 需求。三个处理，即：1）化肥（氮、磷、钾分别为55.2、35.2 和 22.4 kg ha ^-1），2）玉米秸秆（8 t ha ^-1) 和 3) 在 Mollisol 土壤中的玉米-大豆轮作系统中施用非肥料。结果表明，玉米渣处理的大豆种子产量与化肥处理相同，2014 年分别为 2.9 比 3.2 t ha ^-1，2016年分别为 2.7 比 2.6 t ha ^-1和 3.0 比3.2 t ha ^-1。. 3.1 t ha ^-1 in 2018. 使用¹⁵ N标记残留物的后续盆栽试验表明，残留物衍生的N占大豆种子中总N的0.5%，共生固定N的比例达到82%。残渣处理结荚期固定氮量为0.66 g植株^-1，分别比化肥和不施肥处理高 49% 和 41%。N ₂固定的刺激与每个根瘤固定N的增加和大豆根际固氮菌的富集有关。随着玉米渣修正案中，增加的Ñ ₂在生殖周期结节-定影能力，而不是残留物衍生的N，满足用于维持大豆的种子产量的N个需求。在玉米-大豆旋转系统，玉米渣修正案将有助于Ñ ₂固定到部分地代替氮肥对大豆产量黑土。