Response Of Soil Microorganism By Vegetationrestoration In The Agro-pastoral Transitional Zone

Soil microorganisms are important hinge of soil ecosystem material cycle and energy exchange, and microbial system is extremely sensitive to measure the vegetation restoration performance and could earlier indicate the change of ecosystem function. Study the collaborative response of soil microorganisms on the soil environment is helpful to know microbial adaptation to the environment changes and evolution mechanism, promote the healthy development and positive succession of vegetation, and maintain the stability of soil ecosystem function. To understand the response of soilmicroorganismby vegetation restoration on desertification, with the soil of the 4 sand tune types in Yuyang district, and 3 kinds of soil under the arbor, shrub and grass vegetation communities which has restored for 30 years in Yulin desert botanical garden, and 7 different restoration chronosequences soil in Yuyang district, which are located in the southern edge ofMao Wusu Sandland, as the research object.Analyzed theimpactof vegetation restoration on soil microbial quantity,microbial biomass C, N, P content and the ratio, soil enzyme activities and the correlation with soil properties, and the trends of biological characteristics with the change of restoration chronosequences were discussed. The specific results are as follows:(1) Vegetation restoration could significantly improve the biological characteristics of soil. During the changeover process of vegetation recovery prompting desertification soil from reversely flowing to fixed sand dunes, the quantity of soil microbial bacteria, fungi, actinomycetes, soil microbial biomass carbon, nitrogen, phosphorus and the enzyme activity of soil are the highest overall performance for the fixed sand dunes and the lowest for the flowing sand dunes. Fixed sand duneis significantly higher than current sand dunes, mobile sand dunes and half fixed sand dunes.(2) The quantity of soil microorganisms(including bacteria, actinomycetes and fungus); Microbial biomass content is also significantly increased, the largest is artificial shrub, followed by artificial arbor, and the smallest is grassland. Microbial biomass carbon nitrogen ratio and carbon phosphorus ratio of shrub is the smallest,that means the bioavailability of nitrogen and phosphorus is the largest; The soil enzyme activity significantly improve, and the activity of shrubbery is the highest. It shows that in theinterim of vegetation restoration, to the improving effectof soil biological characteristics,shrubs is better the arbors and herbs.(3) Correlation analysis shows that soil microbial biomass C, N, P were highly significant correlation or significant correlation with soil organic matter, total nitrogen, alkali-hydrolyzale nitrogen, total phosphorus and available phosphorus,but show a significant negative correlation with soil bulk density. Soil enzyme activity aiso has extremely significant correlation with soil organic matter, alkali-hydro nitrogen, available phosphorus, total nitrogen and total phosphorus,but a significant negative correlation with the soil bulk density.It indicated that the changes trend under different vegetation communitiesis consistent with physical and chemical properties. Can be used assoil fertility standards to evaluate the level of soil quality.(4) Soil biological characteristicshad sensitive response to different vegetation restoration period, and the change was certain regularity. Characterized by itsignificantly decreasedwith the soil depth deepen, and rise at first and then fall with the the increasing length of recovery. The microbial biomass carbon, nitrogen, soil alkaline phosphatase activity reached the highest value at 30 a of vegetation restoration and then began to decline; microbial biomass phosphorus, soil catalase, saccharase activity reached the peak at 50 a and then decreased significantly. It showed that the improvement of soil microbial characteristics began to decreased during 30 ~ 50 a vegetation restoration when the vegetation transit from shrub to arbor.(5) Vegetation restoration improved the soil properties better than farmlandutilization. In this study, microbial biomass carbon content are not up to the farmland surface standard, but higher than the plough layer; Soil microbial biomass nitrogen, phosphorus, urease, catalase enzyme, saccharase and alkaline phosphatase activity are at or above the level of farmland soil in the process of vegetation restoration.