大豆玉米轮作对暗棕壤肥力及微生态的调控效应OA

To investigate the long-term evolutionary characteristics of farmland soil fertility and crop productivity under different soybean and maize cropping systems,a long-term located experiment was conducted in Heihe City,Heilongjiang Province.Five treatments were established:soybean continuous cropping(SC),maize continuous cropping(MC),soybean-maize rotation(SM),maize-soybean rotation(MS),and fallow(F).The effects of these treatments on soil physicochemical properties,carbon fractions,enzyme activities,microbial communities,and soil partial factor productivity were analyzed,and the soil fertility and microecological mechanisms underlying the alleviation of continuous cropping obstacles by rotation were explored.The results showed that the MS treatment had the highest soil organic matter content and partial factor productivity,which were significantly increased by 23.6%and 19.7%compared with the SC treatment,and by 10.4%and 5.5%compared with the MC treatment,respectively(P<0.05).Compared with the SC and F treatments,the SM treatment significantly increased the contents of dissolved organic carbon,microbial biomass carbon,and microbial biomass nitrogen.The MS treatment exhibited the highest soil organic carbon sequestration,which was increased by 17.9%,6.2%,and 44.8%compared with the SC,MC,and F treatments,respectively.The activities of catalase,sucrase,alkaline phosphatase,and urease in the SM treatment were significantly higher than those in the SC treatment.The activities of catalase and sucrase in the MS treatment were significantly higher than those in the MC treatment,whereas the activities of alkaline phosphatase and urease were significantly lower than those in the MC treatment.The SM treatment significantly enhanced bacterial richness and diversity,as well as fungal richness.The rotation treatments(SM and MS)significantly enriched the beneficial microorganisms Sphingomonas and Bradyrhizobium,while the continuous cropping treatments significantly increased the relative abundance of the pathogens Colletotrichum and Fusarium.In conclusion,maize-soybean/soybean-maize rotation constructs a stable and efficient soil ecosystem by improving soil physicochemical properties,enhancing key enzyme activities,optimizing microbial community structure,and enriching beneficial bacteria,thereby effectively alleviating continuous cropping obstacles.This study provides a theoretical basis for optimizing cropping systems and improving cultivated land quality in the dark brown soil region of Northeast China.