硝化抑制剂施用对水稻产量与氨挥发的影响

通过田间微区试验,应用~(15)N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(240 kg/hm~2)相比,减氮处理(180 kg/hm~2)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~(15)N吸收与利用效率,同时~(15)N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~(15)N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。

Effects of Nitrification Inhibitor on Rice Production and Ammonia Volatilization in Paddy Rice Field

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 the rice production of N180 was significantly lower than N240. For the plots received 180 kg/hm₂urea N, CP application increased the rice grain yield by 15.2% that reached to the rice production in plots received 240 kg/hm₂. However, CP had no impact on rice yield when the N input level came to 240 kg/hm₂. CP application significantly promoted the ₁₅N use efficiency by 11.1~25.0%. And the ₁₅N balance results suggested that CP usage reduced the ₁₅N losses via nitrification-denitrification and runoff by 21.7~28.1%. These probably were the mechanisms of rice yield-increasing. However, CP amendment increased the NH₃ losses by 54.7~110.6%. These results indicated that CP application can maintain a high rice production at a sub-optimal N input level. However, the counter measures should be adopted to control the much higher NH₃ volatilization in paddy soil applied with CP.