Effects Of Conservation Tillage On Fiuvo-aquic Soil Enzyme Activity And Soil Microbial Community And Soil Fertility

A field experiment was carried out to evaluate effects of conservation tillage on fiuvo-aquic soil enzyme activities、microbial community and soil nutrient following a cropping rotation of corn and wheat in Fengqiu National Agro-Ecological Experimental Station, China. The experiment was designed to have8treatments or practices, i.e.,tillage for both corn and wheat(CTWT, all turnover treatment), no-tillage for corn and tillage for wheat annually (CNTWT, conventional tillage treatment), no-tillage for corn and tillage for wheat every four year (CNTW4T, alternate tillage treatment), no-tillage for either corn and wheat(CNTWNT, no-tillage treatment), all turnover treatment with straw incorporated(CTWTS), conventional tillage treatment with straw incorporated (CNTWTS), alternate tillage treatment with straw incorporated (CNTW4TS), no-tillage treatment with straw incorporated (CNTWNTS). The results were as follows:(1) In the whole corn growth period, the4kinds of tested soil enzyme activities, the number of bacteria, fungi, the content of organic matter, microbial biomass carbon and microbial biomass nitrogen were improved by no-tillage and alternate tillage treatment, on the country, the number of soil actinomycete decreased. all turnover tillage treatment depressed the4kinds of tested soil enzyme activities.(2) No-tillage treatment, alternate tillage and straw remaining treatment could improve4kinds of wheat soil enzymatic activities, microbial biomass carbon and nitrogen. The tested soil enzyme activities reached a peak under no-tillage+straw remaining treatment in wheat seedling stage and jointing stage, followed by no-tillage treatment, while which were highest in booting stage and maturity stage under minimal tillage+straw remaining treatment, followed by minimal tillage. Among the8cultivar modes, the soil microbial biomass carbon and nitrogen were highest under no-tillage+straw remaining treatment, followed by no-tillage, minimal tillage+straw remaining and turnover tillage leads to the lowest value.(3) The correlation coefficient among the4kinds of wheat soil enzymatic activities, microbial biomass carbon and nitrogen reached significant level mostly. Cluster analysis further indicated that the treatments could be sorted into three groups according to wheat soil enzemy activity and microbial biomass. Only no-tillage+straw remaining treatments was divided into the highest activity group. It suggested that no-tillage combined with stubble-remaining can effectively increase soil enzyme activity.(4) In the whole corn growth period, no-tillage and alternate tillage could improve the content of soil organic matter, soil nitrogen, soil phosphorus, soil potassium and soil pH value, while all turnover tillage treatments reduced all above but the soil pH value, it had almost no influence on soil pH.(5) The correlation coefficient among maize soil urease、alkaline phosphate、sucrase、 dehydrogenase、soil microbe number and soil nutrient reached significant level mostly. The maize order of soil quality index from high to low was no-tillage treatment, alternate tillage, all turnover treatment and conventional tillage.