Soil nitrogen (N) supply for wheat N uptake can be manipulated through legume and fertilizer N inputs to achieve yield potential in low‐rainfall sandy soil environments. Field experiments over 2 years (2015–2016) were conducted at 2 different sites in a low‐rainfall sandy soil to determine the soil N supply capacity relative to wheat N uptake at key growth stages, after a combination of crop residue (removed, wheat or lupin) and fertilizer N (nil, low or high N) treatments were manipulated to improve wheat yield. We measured the temporal patterns of the soil profile mineral N and PAW to 100 cm depth, wheat aerial biomass and N uptake in both years. In 2016 we also measured the disease incidence as a key environmental variable. There was 35 kg ha⁻¹ more soil mineral N to 100 cm depth following lupin than wheat residues at the end of the fallow on average in both years. In a below average rainfall season, wheat biomass produced on lupin residues was responsive to N input with soil profile mineral N depleted by increased crop N uptake early in the season. In an above average rainfall season, a higher soil mineral N supply increased actual and potential grain yield, total biomass, N uptake, harvest index and water use efficiency of wheat, regardless of the source of N. Our study showed that the combination of lupin residues with high N rate increased soil profile mineral N at early growth stages, providing a greater soil N supply at the time of high wheat N demand, and the inclusion of a legume in the rotation is critical for improving the N supply to wheat, with added disease break benefits in a low‐rainfall sandy soil environment.

中文翻译：

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来自豆类残留物和肥料的氮输入相结合，改善了小麦的早期氮供应和吸收

可以通过豆类和肥料氮素的投入来控制小麦吸收氮素的土壤氮素供应，以在低雨量沙质土壤环境中实现增产潜力。在作物残渣（去除的小麦）组合后，在低降雨沙质土壤的两个不同地点进行了为期两年（2015-2016年）的田间试验，以确定在关键生长阶段相对于小麦氮吸收的土壤氮供应能力。或施用羽扇豆）和氮肥（零氮，低氮或高氮），以提高小麦产量。我们在这两年中测量了土壤剖面矿质N和PAW到100 cm深度，小麦空中生物量和N吸收的时间模式。2016年，我们还将疾病发病率作为关键环境变量进行了测量。面积为35千克公顷^-1在这两个年份，羽扇豆产后到100厘米深度的土壤矿物质N的平均含量要高于小麦残留量。在低于平均降雨量的季节，羽扇豆残渣产生的小麦生物量对氮的输入有响应，土壤剖面中的矿质氮因季节初作物氮吸收的增加而减少。在高于平均降雨量的季节，较高的土壤矿质氮供应量会增加小麦的实际和潜在谷物产量，总生物量，氮素吸收，收获指数和水分利用效率，而与氮素的来源无关。我们的研究表明羽扇豆的组合高氮含量的残留物在生长早期增加了土壤剖面的矿质氮，在小麦高氮需求时提供了更多的土壤氮供应，轮作中加入豆类对于改善小麦的氮供应至关重要，