【摘要】 利用长期定位试验资料,评价了东北黑土增施有机肥条件下玉米连作(CMC)、玉米-大豆轮作(MSR)和大豆连作(CSC)等种植模式对土壤微生物数量与结构、土壤理化性质的影响及其相互关系。结果表明:0~40 cm土层内,土壤微生物总量呈CMC>MSR>CSC趋势,且差异显著(P<0.05);细菌数量占微生物总量的比重呈CMC>MSR>CSC的趋势,而真菌和放线菌所占比重均呈CSC>MSR>CMC的相反趋势;CMS处理下的土壤容重最低,但土壤有机碳、全氮、有效氮、有效磷含量均显著高于其他处理;相关分析发现细菌和放线菌数量与土壤容重显著负相关,但与土壤有机碳、全氮、有效氮显著正相关,而真菌数量占微生物总量的比例则与土壤容重显著正相关,与土壤有机碳、全氮、有效氮显著负相关。综上所述,长期玉米连作结合有机肥施用,有利于改善土壤理化性状,增加土壤微生物数量,但以细菌增加为主,微生物多样性呈下降的趋势。更多还原

【Abstract】 Based on the long-term experiment in black soil region of Northeast China, the effects of cropping regimes with organic manure application on soil microbial amounts and structure, soil physical and chemical properties were analyzed. In the 0- 40 cm soil depth, soil microbial amount under continuous corn cropping(CMC) treatment was significantly higher than that under the corn-soybean rotation(MSR) and the continuous soybean cropping(CSC)treatments(P < 0.05). The ratio of bacteria to total soil microbes under CSC treatment was significantly higher than that under CMC and MSR treatments, whereas the ratio of fungi and actinomycetes to total soil microbes showed opposite tendencies. Soil bulk density was significantly lower under CMC treatment than under MSR and CSC treatments. Furthermore, CMC treatment achieved the highest soil organic carbon, total nitrogen, available nitrogen,and available phosphorus among the treatments. According to the correlation analysis, significantly negative correlation was found between the amounts of bacteria, actinomycetes and soil bulk density, whereas significantly positive correlation was found between the amounts of bacteria, actinomycetes and soil organic carbon, total nitrogen, and available nitrogen. Moreover, the ratio of fungi to total soil microbes showed positive correlation with soil bulk density,but negative correlation with soil organic carbon, total nitrogen, and available nitrogen. Present study indicated that long-term continuous corn cropping with organic manure amendment could improve soil quality and increase soil bacteria amount. However, the predominance of bacteria in soil microbial community under continuous corn cropping may result in the decrease in microbial diversity.更多还原