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灌淤土是含有大量泥沙的黄河水流经长期灌溉而形成,其在宁夏土类中占有一定的比例。为了阐明长期施肥对灌淤土土壤微生物的影响,以宁夏灌淤土土壤肥力监测基地为试验平台,采用平板稀释法和Biolog微生物鉴定系统研究了长期施肥条件下土壤微生物特征的变化。结果表明:长期NP、NK、PK、NPK施肥处理显著降低了土壤细菌数量和土壤微生物总数,细菌数量降低达50%以上。M和1.5NPKM处理增加了土壤放线菌数量,增加的幅度达95%左右,单施氮肥处理显著降低了土壤放线菌数量。NPK和NPKM处理提高了土壤微生物群落对羧酸类、碳水化合物类和酚类碳源的代谢活性,1.5NPKM处理提高了微生物群落对胺类碳源的代谢活性,说明长期的NPK及NPK配合施用有利于土壤微生物活性的提高。施肥处理均不同程度地提高了土壤微生物群落的SHANNON多样性指数但降低了均匀度指数。
Irrigation silt is formed by long-term irrigation of the Yellow River with a large amount of sediment, which occupies a certain proportion in Ningxia soil. In order to clarify the effect of long-term fertilization on the soil microorganisms in irrigated silts soil, the change of soil microbial characteristics under long-term fertilization was studied by the plate dilution method and the Biolog microbial identification system using the soil fertility monitoring base of Ningxia irrigated soil as the experimental platform. The results showed that long-term NP, NK, PK, NPK fertilization significantly reduced the number of soil bacteria and soil microbes, and the number of bacteria decreased by more than 50%. M and 1.5NPKM treatment increased the number of soil actinomycetes, an increase of about 95%, single application of nitrogen fertilizer significantly reduced the number of soil actinomycetes. NPK and NPKM treatments increased the metabolic activity of soil microbial communities to carboxylic acids, carbohydrates and phenolic carbon sources. 1.5NPKM treatment increased the metabolic activity of microbial communities to amine carbon sources, indicating long-term application of NPK and NPK Is conducive to the improvement of soil microbial activity. Fertilization treatments increased the SHANNON diversity index of soil microbial communities to a certain extent but decreased the evenness index.