硝化/脲酶抑制剂对石灰性潮土N_2O减排效果及氮素转化的比较

Effects of nitrification/urease inhibitors on mitigating N_2O emission and transformation of N from calcareous fluvo-aquic soil

以华北平原石灰性潮土为对象,采用室内静态培养方法,在土壤中添加不同类型的抑制剂(硝化抑制剂、脲酶抑制剂),监测N_2O和无机氮随时间变化的特征,对比分析何种添加剂减排N_2O效果明显,为其在农业生产中的应用提供科学依据。试验设置7个处理:不施肥(CK);只施尿素(U);尿素和2-氯-6-三氯甲基吡啶(Nitrapyrin,由中化集团公司代理)同时施用(U+NP);尿素和推荐用量2-氯-6-三氯甲基吡啶(Nitrapyrin,由陶氏化学公司代理)同时施用(U+NPD);尿素和2倍推荐用量2-氯-6-三氯甲基吡啶(Nitrapyrin,由陶氏化学公司代理)同时施用(U+2NPD);尿素和双氰胺同时施用(U+DCD);尿素和N-丁基硫代磷酰三胺同时施用(U+n BPT),共培养56 d。在培养第1、2、3、5、7、10、14、19 d采气测定N_2O和CO_2,气体监测到培养第19 d为止;在培养的第0、1、3、7、14、21、28、42、56 d进行破坏性取样,监测土壤氮素转化。结果表明:供试硝化抑制剂能够降低87.4%~99.6%的N_2O排放,脲酶抑制剂降低30.0%N_2O排放;氮素转化过程中,硝化抑制剂处理只有0.03%~0.84%的铵态氮转化为N_2O,脲酶抑制剂处理有4.69%的铵态氮转化为N_2O。DCD和陶氏公司Nitrapyrin产品在抑制N_2O排放的效果上无显著差异,与推荐用量陶氏公司Nitrapyrin相比,施用2倍推荐量并没有显著降低N_2O排放。综上,供试硝化抑制剂能够显著降低石灰性土壤N_2O的排放,减排效果最好的处理为U+NP,陶氏公司Nitrapyrin产品按推荐用量施用即可。

N2O emission can be reduced by nitrification and urease inhibitors which are also connected to soil N transformation. An incubation experiment was conducted in calcareous fluvo-aquic soil in order to compare the effects of different nitrification/urease inhibitors on N2O emissions and N transformation, find out proper nitrification/urease inhibitor for this soil, provide scientific basis for applying proper inhibitors in agricultural production. Seven treatments were set：No fertilizer（CK）, Urea（U）, Urea plus Nitrapyrin belonged to the Sinochem Group（U＋NP）, Urea plus recommended dosage of Nitrapyrin belonged to the Dow Chemical Company（U＋NPD）, Urea plus double recommended dosage of Nitrapyrin belonged to the Dow Chemical Company（U＋2NPD）, Urea plus Dicyandiamide（U＋DCD） and Urea plus nBPT（U＋nBPT）. The incubation last for 56 days. Gases were sampled on the first, second, third, fifth, seventh, tenth, fourteenth and nineteenth day of the incubationfor N2O and CO2 analysis, soils were sampled on the zero, first, third, seventh, fourteenth, twenty-first, twenty-eighth, forty-second and fifty-sixth day of the incubation for N transformation analysis. The main results showed that the experimental nitrification/urease inhibitors reduced N2O emissions in different degrees, from 87.4% to 99.6% for nitrification inhibitor treatments while 30% for U＋nBPT treatment compared with CK.There was only 0.03% to 0.84% of the ammonium transformed into N2O for nitrification inhibitor treatments, while 4.69% for U＋nBPT treatment.There was no significant difference on mitigating N2O emissions between U＋DCD and U＋NPD, double recommended dosage of Nitrapyrin did not increase the effect on reducing N2O emission correspondingly. In summary, the experimental nitrification inhibitors significantly reduced N2O emissions from the calcareous fluvo-aquic soil, and the nitrification inhibitor effects were better than urease inhibitor. The best one was U＋NP treatment.