Effects of nitrification inhibitors on nitrification inhibition and nitrite accumulation in calcareous soil | 石灰性土壤中不同硝化抑制剂的抑制效果及其对亚硝态氮累积的影响

Chinese. 【目的】比较不同硝化抑制剂3, 4-二甲基吡唑磷酸（DMPP）、双氰胺（DCD）、2-氨基-4-氯-6-甲基吡啶（AM）和硫脲（TU）在石灰性土壤中的抑制效果,明确其对土壤中亚硝态氮累积的影响。【方法】采用室内培养的方法,比较了硝化抑制剂对石灰性土壤中铵态氮、硝态氮、亚硝态氮、pH、表观硝化率和硝化抑制率的影响。【结果】施用TU和未施用硝化抑制剂的土壤在培养初期（1―3 d）出现了亚硝态氮的累积。TU的施用导致土壤pH下降至硝化作用适宜的范围,从而促进了硝化作用进程;施用硝化抑制剂DMPP、DCD和AM的土壤几乎未检测到亚硝态氮,且硝化抑制效果明显,硝化过程延滞35―39 d。硝化抑制率强弱顺序10%DCD＞1%DMPP＞5%AM（这里的数值代表硝化抑制剂的施入量占施入纯N量的百分比）。【结论】DMPP、DCD和AM的施用能显著抑制亚硝态氮的产生,并能显著抑制硝化作用进程（P＜0.01）;相反,TU的施用却促进了硝化作用的进程。供试的4种硝化抑制剂中,以10%DCD（纯N含量）处理的硝化抑制率最高,其次是1%DMPP。

English. 【Objective】The objective of the study was to determine the influences of four different kinds of nitrification inhibitors, DMPP, DCD, AM and TU, on soil nitrite accumulation, and to select the best nitrification inhibitor for nitrogen fertilizer in calcareous soil.【Method】The contents of ammonium nitrogen, nitrite nitrogen, nitrate nitrogen and pH were measured, and apparent nitrification rate and inhibitory rate of different nitrification inhibitors were calculated.【Result】The results showed that under the experimental conditions (60% of water hold capacity, 25℃), little nitrite nitrogen was found in the soil treated with nitrification inhibitors DMPP, DCD, and AM, however; while some nitrite nitrogen was found in the TU treatment in the beginning eight days. The nitrification inhibition rate was in the order of 10%DCD＞1%DMPP＞5%AM (depending on the amount of applied pure N). DMPP, DCD and AM treatments induced nitrification process lag behind 35-39 d.【Conclusion】DMPP, DCD and AM could significantly inhibit the accumulation of nitrite nitrogen in calcareous soil. The inhibitory effects of DMPP, DCD and AM were evident, while that of TU was not.