Study On Variation Characteristics Of Soil Microbial Community For Apple Orchard By Interplanting Herbage In Weibei

Grass cultivation, which is a new orchard management model, plays an important role in improving orchard soil conditions. In recent years, most researches are mainly focused on the effect of interactions with the fruit trees, but it is still weak in the mechanism of interactions with the fruit trees. Based on the background of apple orchard with Interplanting grass in weibei, this study investigated species composition and quantity change of soil microorganism for orchard with grass cultivation, and the carbon source utilization characteristics of microbial community was explored by using the laboratory analysis method, the relationship between soil microbial community with soil physichemical properties was analyzed, which could further provide a reference for revealing driving mechanism of ecological process of orchard soil. The main results were as follows:(1) Compared with clear tillage, grass cultivation could significantly increase the quantity of soil microorganism, interplanting white clover, interplanting small crown flower, interplanting crowtoe, interplanting Cocksfoot could improve by 70.36 percent, 77.70 percent, 78.56 percent and 21.46 percent, respectively. But there exsited differences in the quantity of soil microorganism in different grass treatments, which legume herbages increased higher than gramineous herbages for soil bacteria, and gramineous herbages increased higher than legume herbages for soil actinomycetes and fungi.(2) Soil microorganism of apple orchard with Interplanting grass had obvious spatial and temporal distribution characteristics. From the aspect of season, the quantity of soil microorganism reached the maximum in spring, the next in spring and the minimum in summer. In the vertical distribution, the quantity of soil microorganism decreased with the increase of soil depth.(3) Grass cultivation could provide metabolic activity of soil microbial community, but soil microbial activity had significant difference among different treatments and in the order of white clover >small crown flower > crowtoe >Cocksfoot >clear tillage, which legume herbages were superior than gramineous herbages. Soil microbial activity decreased with the increase of soil depth. There exsited seasonal differences in soil microbial activity, which grass treatments were higher in spring and autumn, and lower in summer, yet clean tillage presented that the seasonal differences were not obvious.(4) Different treatments presented different carbon source utilization characteristics. In spring and autumn, grass treatments improved carbon source metabolic ability of soil microbial community and had higher utilization ability of sugars, amino acids, polymers and carboxylic acids, but different grass treatments had differences in the utilization of carbon sources. In summer, the utilization of carbon sources of different treatments were relative less.(5) Soil microbial diversity index had difference among different treatments, and the average well colour development, shannon index, richness index and McIntosh index of white clover were large.(6) The correlation analysis showed that soil microbial quantity, activity and diversity index were all significantly positively correlated with soil nutrients and organic matter, and these index had significantly or extremely significantly negative correlation with soil bulk density, but not significant correlation with soil moisture and pH; Path analysis showed that the direct action of total nitrogen and organic matter and interactions of two factor produced great influences on soil microbial quantity and activity.