3,5-二甲基吡唑(DMP)施用后土壤硝化作用潜势及微生物群落动态变化研究

采用室内培养试验方法,从3,5-二甲基吡唑施用后土壤硝化作用潜势、参与氮转化的主要生理菌群、土壤微生物群落的数量及其生理活性等的动态变化入手,研究了新型硝化抑制剂3,5-二甲基吡唑(DMP)的施用对土壤硝化作用及生物学质量的影响。结果表明,适量DMP的施用可在一定时间内显著降低土壤的硝化作用潜势和土壤氨氧化菌的数量,刺激土壤三大微生物群落的增殖,但细菌、真菌和放线菌对DMP的剂量反应不同。土壤细菌数量呈现随DMP用量增加而增加的趋势,真菌和放线菌数量在培养28d之前则以中等剂量处理的为最高。超高量DMP的施用则强烈抑制土壤氨氧化菌的生长,土壤硝化作用潜势在整个培养期间一直维持在一个较稳定的低水平状态,且在施用前期对真菌和放线菌的增殖及总的微生物生理活性表现了一定的抑制效应,微生物商降低,qCO2值增大;在施用14d后,这种负效应逐渐缓解,进而表现出一定的刺激效应。DMP施用对土壤反硝化细菌影响不大。

Dynamics of Soil Nitrification Potential and Microbial Populations After Applying 3,5-dimethylpyrazole

Using incubation test,the effects of a new nitrification inhibitor 3,5-Dimethylpyrazole(DMP) on soil nitrification and related microbiological characteristics were studied.The results showed that appropriate dosage of DMP could significantly decrease the potential of soil nitrification and the individuals of ammonia-oxidizing bacteria in a definite duration.Soil bacteria increased with increasing dosage of DMP,while soil fungi and actinomyces had the greatest amounts in the first 28 days of incubation under medium dosage of DMP.With the high application dosage of DMP,ammonia-oxidizing bacteria suffered a strong inhibition throughout the incubation duration,and thus,the potential of soil nitrification was at a low level all along.In the first 14 days,the proliferation of soil fungi and actinomyces was inhibited to some degree under high application dosage of DMP,microbial quotient decreased,and qCO2 value increased,but thereafter,such effects were relaxed gradually.Applying DMP had little effect on soil denitrifiers.