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通过田间小区试验研究了氮肥一次基施对高肥力土壤上冬小麦产量、吸氮量及氮肥利用率的影响 ,旨在了解高肥力土壤上减少基肥氮的可行性。结果表明 ,高肥力土壤上冬小麦产量对氮肥的反应不明显 ,而施用氮肥显著增加了冬小麦吸氮量。根据差值法计算结果 ,当施氮量为 75、1 1 2 .5和 1 5 0 kg/ hm2 时冬小麦的氮肥利用率分别为 1 6 .0 %、1 4 .5 %和1 3.5 % ,表明多达 84 %～ 86 .5 %以上的基肥氮未被作物吸收利用。氮平衡计算的结果进一步表明 ,未被当季小麦利用的肥料氮主要以无机氮的形式残留于 0～ 1 m土体中 ,当施氮量分别为 75、1 1 2 .5和 1 5 0 kg/ hm2时氮肥的土壤残留率依次为83.3%、4 6 .0 %和 5 8.8% ,而相应的表观损失率为 0 .5 %、38.9%和 1 9.0 %。由此可见 ,在高肥力土壤上应严格控制基肥氮的用量或不施基肥 ,否则将造成氮素资源的大量浪费。
The field experiment was conducted to study the effects of primary nitrogen fertilization on winter wheat yield, nitrogen uptake and nitrogen use efficiency in high-fertility soils to understand the feasibility of reducing basal fertilizer nitrogen in high-fertility soils. The results showed that the response of winter wheat yield to nitrogen fertilizer was not obvious in high-fertility soils, while nitrogen application significantly increased the nitrogen uptake of winter wheat. According to the difference method, nitrogen use efficiency of winter wheat was 16.0%, 14.5% and 15.5% when nitrogen rates were 75,1 1 2.5 and 150 kg / hm2 respectively, As much as 84% ~ 86.5% of basal nitrogen was not absorbed by crops. The results of nitrogen balance calculation further showed that fertilizer nitrogen not used by the seasonal wheat remained mainly in the form of inorganic nitrogen in 0-1 m soil. When the nitrogen application rates were 75, 115 and 150 kg / hm2, the soil residual rates of nitrogen fertilizers were 83.3%, 46.0% and 58.8%, respectively, while the corresponding apparent loss rates were 0 .5%, 38.9% and 1 9.0%. Thus, we should strictly control the amount of basal nitrogen or non-basal fertilizer on high-fertility soil, otherwise it will cause a lot of waste of nitrogen resources.