中文摘要：

通过田间微区试验，应用15N标记技术研究两个施氮水平下硝化抑制剂CP施用对水稻产量、氮素利用率、氮素土壤残留和氨挥发的影响。结果表明：与推荐施氮处理（240kg／hm2）相比，减氮处理（180kg／hm2）水稻产量明显降低，但是减氮处理下施用硝化抑制剂CP后增产15．2％，差异显著，并且达到了推荐施氮处理下的产量水平。而推荐施氮处理下施用硝化抑制剂对水稻产量反而没有显著影响。施用硝化抑制剂可显著提高11．1％～25．0％的15N吸收与利用效率，同时15N平衡计算结果表明稻田施用硝化抑制剂减少了21．7％～28．1％的硝化-反硝化、径流等途径15N损失，这可能是CP施用增加水稻产量的机理之一。然而，施用硝化抑制剂会增加54．7％～110．6％的氨挥发排放。因此，在水稻生产过程中施用硝化抑制剂CP时要进一步减施氮肥才有明显的增产效果，同时还需要采取一定的措施来控制氨挥发。

英文摘要：

A micro-plot scale field experiment with two labeled 15N-urea input level, i.e., 180 kg/hm2 and 240 kg/hm2, was carried out to study the effects of nitrification inhibitor （2-Chloro-6-（trichloromethyl）-pyridine, CP） application on rice grain yield, N use efficiency, soil residual N and NH3 volatilization in a paddy rice field. The results showed that rice production of N180 was significantly lower than N240. For the plots of 180 kg/hm2 urea N, CP application increased the grain yield by 15.2% that reached to rice production in plots of 240 kg/hm2. However, CP had no impact on rice yield when N input level was 240 kg/hm2. CP application significantly promoted 15N use efficiency by 11.1%-25.0%. And the 15N balance results suggested that CP usage reduced 15N losses by 21.7%-28.1% via nitrification-denitrification and runoff. These probably were the mechanisms of rice yield increase. However, CP amendment increased NH3 losses by 54.7%-110.6%. These results indicate that CP application can maintain a high rice production at a sub-optimal N input level and meanwhile measures should be adopted to control higher NH3 volatilization in paddy soil applied with CP.