Studies On Effects Of Straw Returning On Black Soil Soil Enzyme And Diversity Of Bacteria

With the increase of years of black soil reclamation, natural factors and over-exploitation of human predatory made farmland quality degradation, increasing year on year, the number and diversity changes of bacteria in the soil gradually cause for concern with the decline of soil quality, this thesis research change law of soil microorganism number and microbial biomass (C、 N) and soil enzymes (urease, catalase) of straw returning, and research effects of straw returning on the number and the biodiversity of bacteria in soil applying PCR-DGGE, to analyze and explore that straw returning whether influence bacterial diversity in agricultural soil ecosystems. It provided a theoretical basal data to reclaim degraded black soil and improve the quality of black soil, as well as provide a scientific reference to application of straw returning technology.The experiment proved the straw returning treatments that applied active agents and cellulose-decomposing microorganisms increased soil urease and catalase activity through treatments that applied active agents and cellulose-decomposing microorganisms to the straw, soil urease activity of different straw returning treatments show that application of straw and active agents>application of straw and Degradation bacteria>composting straw>organic fertilizer>straw and Degradation bacteria and active agents>not applied straw agents. The treatment that applied straw and the active agent was the most obvious improvement on urease activity.The soil catalase activity of different straw returning treatments show that application of organic fertilizer>composting straw>straw and Degradation bacteria and active agents>application of straw and active agents>not applied straw agents. The treatment that applied organic fertilize and applied composting straw were more obvious improvement on catalase activity than other treatments.Experiments show that different straw returning treatments can increase the number of bacteria, the number of soil bacteria of treatments show that application of straw and active agents>composting straw>organic fertilizer>straw and Degradation bacteria>straw and active agents>not applied straw agents, which applied straw and Degradation bacteria and the active agent was the most obvious improvement on the number of bacteria.The number of soil fungi of treatments show that application of composting straw> organic fertilizer>straw and degradation bacteria>straw and degradation bacteria and active agents>straw and active agents>not applied straw agents.The number of soil fungi of treatments was only obvious difference effect by application of composting straw and straw and degradation bacteria and active agents, other treatments was not. Experiments show that straw returning increased the content of microbial biomass carbon, microbial biomass carbon of treatments shows that straw and degradation bacteria>straw and active agents>composting straw> organic fertilizer>straw and degradation bacteria and active agents> not applied straw agents, the content of microbial biomass N was not obvious difference effect.The number of bands and the diversity index in mature period and seedling stage were not significant differences among the treatments, the number of DGGE bands and the diversity index in mature period was significantly lower than the treatment that applied straw, the number of bacterium bands and the diversity index of different straw returning treatments show that application of composting straw>straw and Degradation bacteria and active agents>organic fertilizer>straw and Degradation bacteria>straw and active agents>not applied straw agents, the treatment that applied composting straw was the most obvious increase in the number of bacterium bands and the diversity index, followed by straw and Degradation bacteria and the active agent (GNH*).The number of bands and the diversity index of applied straw treatments in seedling stage were higher than the treatment that was not applied straw, but did not form a significant difference, the number of bacterium bands and the diversity index of different straw returning treatments show that application of composting straw>straw and Degradation bacteria and active agents>organic fertilizer>straw and Degradation bacteria>straw and active agents>not applied straw agents, cluster analysis show that the treatment of application of straw had a higher similarity in the same branch, had a lower similarity to the treatment that was not applied straw.