The urease inhibitor [N‐(n‐butyl) thiophosphoric triamide (NBPT)] and the nitrification inhibitor (NI) 3,4‐dimethyl pyrazole phosphate have been reported to conserve urea‐based N fertilizers by reducing N losses. However, their effects on crop yield and N uptake are inconsistent and fall‐applied N fertilizers are usually less efficient than spring applications. We conducted a 2‐yr field study on contrasting soils [Carman sandy loam (CSL) and Portage clay loam (PCL)] on the effects of NBPT with and without NI on grain yield, grain N removal, and crop N uptake from fall and spring surface‐applied urea‐based fertilizers. Fertilizer treatments (75 or 100 kg N ha⁻¹) were urea and urea ammonium nitrate (UAN) with and without NBPT or NBPT + NI. Canola (Brassica napus L.) and wheat (Triticum aestivum L.) yield, N removal, and N uptake were not consistently greater for urea and UAN treated with inhibitors than for untreated urea and UAN. The inhibitors’ effect on yield and N uptake was observed in urea treated with NBPT in CSL but not PCL. Although agronomic efficiency was significantly greater for spring‐applied untreated urea or UAN than fall‐applied urea or UAN with and without inhibitors in PCL, no significant difference appeared between fall‐applied urea or UAN treated with inhibitors and spring‐applied untreated urea or UAN in CSL. The N conserved by the inhibitors did not appear in the soil as nitrate‐N. Although inhibitors may reduce N losses, their use to increase yield and bridge the efficiency gap between fall‐ and spring‐applied urea‐based fertilizers may be site‐specific.

中文翻译：

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用尿素酶和硝化抑制剂处理的秋季施肥与春季施肥的尿素基肥料的效率II。作物产量和氮素利用效率

据报道，脲酶抑制剂[ N-（正丁基）硫代磷酸三酰胺（NBPT）]和硝化抑制剂（NI）3,4-二甲基吡唑磷酸酯可通过减少氮的损失来保护基于尿素的氮肥。但是，它们对作物产量和氮素吸收的影响不一致，而且秋季施用的氮肥通常比春季施用的效率低。我们进行了为期2年的田间研究，研究了对比土壤[Carman沙壤土（CSL）和Portage黏土壤土（PCL）]含和不含NI的NBPT对秋季和秋季土壤氮素吸收和作物氮素吸收的影响。春季表面施用的尿素基肥料。化肥处理（75或100 kg N ha ^-1）为尿素和有或没有NBPT或NBPT + NI的尿素硝酸铵（UAN）。油菜籽（油菜L.）和小麦（小麦L.）抑制剂处理的尿素和UAN的产量，氮去除量和N吸收量并未始终高于未处理的尿素和UAN。在CSL中用NBPT处理的尿素中观察到了抑制剂对产量和氮吸收的影响，而在PCL中未观察到。尽管PCL中春季施用的未处理尿素或UAN的农艺效率显着高于秋季施用的尿素或UAN，但在抑制剂中和未施用抑制剂的秋季施用尿素或UAN与春季施用的未处理尿素或UAN的农作效率无显着差异。在CSL中。抑制剂保守的氮在土壤中并未以硝态氮的形式出现。尽管抑制剂可以减少氮素的损失，但是它们可以用来提高产量并弥合秋季和春季施用的尿素基肥料之间的效率差距，这可能是因地制宜的。