15N示踪控释氮肥的氮肥利用率及去向研究

选用¹⁵N同位素标记的新型回收塑料包膜控释肥和大颗粒尿素，采用池栽试验研究夏玉米-冬小麦轮作体系中肥料氮的去向及利用率。结果表明，整个轮作体系中，控释肥处理（PCU）作物吸收的肥料氮为241.03 kg/hm，高于尿素处理（Urea)的211.02 kg/hm。控释肥处理施用的肥料氮主要残留在0~40 cm土层，而尿素处理则残留在0~60 cm土层，控释肥延缓了肥料氮向土壤深层迁移的趋势。在夏玉米和冬小麦轮作体系中，控释肥处理的氮肥利用率（32.86%，32.47%）高于尿素处理（28.23%，30.16%）。在冬小麦季，控释肥处理损失率相比尿素处理从36.07% 降至28.75%，而夏玉米季，控释肥处理损失率相比尿素处理从37.17%降至29.50%。玉米季控释肥处理与尿素处理差异不显著，但在冬小麦季控释肥处理的产量显著高于尿素处理。因此，在玉米和小麦整个生长季，新型回收塑料包膜控释肥的养分释放与作物养分需求吻合，既提高氮肥利用率，也降低了肥料氮的损失。

Nitrogen Recovery and Fate of Polymer Coated 15N-urea Fertilizers under Corn-Wheat Rotation

A pool experiment was conducted to study the fate and use efficiency of ¹⁵N-labeled urea and a newly developed polymer coated urea (PCU) on an Argosols in Shandong province, on processing a corn (Zea mays L.)-winter wheat (Triticum aestivum L.) rotation systems in 2009 and 2010. Plant N uptake of corn and wheat from PCU derived N was higher than that from urea derived N (241.03 kg/hm and 211.02 kg/hm). For wheat losses rate of ¹⁵N-PCU rather than ¹⁵N-urea decreased from 36.07% to 28.75%, while for corn from 37.17% to 29.50%. The majority of N derived from PCU remained in the 0 to 40 cm depths, while from urea in the 0 to 60 cm depths, which indicated that PCU treatment can reduce the fertilizer N to migrate to the deeper soil. Yield of corn were similar whether urea or PCU was used, but yield of wheat with PCU treatment was significantly higher than that with urea treatment. Nitrogen use efficiency (NUE) of ¹⁵N-PCU (32.86%, 32.47%) was higher than ¹⁵N-urea (28.23%, 30.16%) during the corn and wheat rotation system. Result indicated that N release of PCU in synchrony with crop N need resulted in the considerable improvement of NUE at the whole growth of corn and wheat, while reducing both fertilizer and soil N losses.