Soil Nutrient, Microorganism And Enzyme Activities Under Different Artificial Sand-Fixing Forests In The Yulin Sand Area

Because of the deterioration of natural conditions, overgrazing, excessive cultivation and over-irrational, Maowusu sandland has become one of the serious desertification regions. In the sand to establish artificial vegetation, can prevent soil erosion, soil organic matter and promote the accumulation of clay, the surface crust to form, The capability of artificial sand-fixing vegetation could fix the sand, and promote soil growing. soil microorganism and enzymes activities are the important components of soil, they play an important role in nutrient cycle, the improvement of soil fertility, the removal of pollutants. However, there were seldom systematic researches about combination in China and even abroad. Therefore, this study has important theory value and practical significance.In this study, the soil under Hedysarum scoparium×Hedysarum mongolicum,Salix psammophila, Hedysarum mongolicum, Hippop haerhamnoides, Pinus sytvestris var. mongolica, Ponulus hopeiensis forest in the sandy plant garden of Yulin sand area in Maowusu sand land are target, by field investigations and laboratory analysis to study the different ecological recovery mode distribution of soil microorganisms. The change of soil micro-flora and the evolution of soil microbial activity in the Process of Ecosystem Restoration in Yulin sand area were studied. The correlation analyses between soil microbial population and soil fertility was researched in order to propose agro-biology quality index of soil microbial in the process of Ecosystem Restoration. It provides scientific references for the evaluation of Environment Effects of Different Artificial Sand-fixing Forests scientifically and objectively. Main conclusions are as follows:1.After artificial plantations were set up, soil nutrients have been improved greatly, multiple analysis revealed that reached a significant level; soil samples under Hedysarum scoparium×Hedysarum mongolicum of the available nitrogen, total nitrogen, total phosphorus, total potassium and organic matter content under Hedysarum scoparium×Hedysarum were increased with the growth years of growth. Hedysarum scoparium×Hedysarum mongolicum improve the soil chemical properties to rise bigger than Hedysarum mongolicum; the soil chemical properties under Pinus sytvestris var. Mongolica and Ponulus hopeiensis has improved significantly. With the extension of vegetation period soil nutrients under Pinus sytvestris var. Mongolica has improved significantly. Drinfting sand dune profiles show that the soil nutrient content were higher in the soil top floor and bottom floor and in the middle were lower.2.The results showed that sand was determined to establish plantations after the number was significantly higher than that Drinfting sand dune microorganisms, in particular, Hedysarum scoparium×Hedysarum mongolicum, Pinus sytvestris var. Mongolica, Hippop haerhamnoides were More effectively to improve the soil microbial environment, the number reached 3.3×10⁶g^-1,1.9×10⁶g^-1,1.4×10⁶g^-1 Hedysarum scoparium×Hedysarum mongolicum number was significantly higher than that Hedysarum mongolicum; plantation soil bacteria and actinomycetes mainly concentrated in the 0-20 cm soil, surface soil fungi number affected by the vegetation cover Larger. Hedysarum scoparium×Hedysarum mongolicum with soil microbial life extension of the number of significant changes in the pattern of growth; with the growth years of cultivation of Pinus sytvestris var. Mongolica soil bacteria increase significantly, and the soil antinomies and soil fungi are planted reached the maximum in 20 year.3. Soil enzymes activities of Hedysarum scoparium×Hedysarum mongolicum and Salix psammophila were overall higher, the single structure Hedysarum mongolicum enzymes activities was low. In addition, four soil enzymes activities of Ponulus hopeiensis was higher, Ponulus hopeiensis improved soil fertility in more satisfactory results. In Hedysarum scoparium×Hedysarum mongolicum planted before 30 years soil enzymes activities increased significantly. soil alkaline phosphatase, Urease activity of Pinus sytvestris var. Mongolica as the age increases significantly enhanced, soil Sucrase Catalase also enhanced but did not reach significant levels. Plantation soil enzymes activities mainly concentrated in the 0-5 cm soil, with the increase of soil depth, enzymes activities decline.4. Correlation analyses showed that Correlation between soil bacteria and the number and soil chemical properties reached significant level except Available N content, especially with soil organic matter content reached a higher significant correlation. The correlation between the antinomies and soil Sucrase, Catalase, Alkaline phosphatase was significant, but there was no significant correlation between soil Urease and microorganisms. Soil organic matter and soil bacteria, soil Urease, Sucrase, Catalase, Alkaline phosphatase has significant correlation indicated that soil organic matter was the important storage bases of soil nutrients and sources of bacterial and enzymes activity. The significant correlation between the Four enzymes statemented that various soil enzymatic role was not isolated each other; they mutually influenced soil and jointly promoted soil nutrient cycling. 5. because of the close correlation between the number of soil microorganisms, enzymes activities and soil nutrients between the soil and the relative stability of enzymes, particularly soil organic matter and soil bacteria, soil Urease, Sucrase, Catalase, Alkaline phosphatase had a significant correlation, the number of soil microorganisms, enzymes activities can be as soil fertility indicators of Yu Lin sandarea. The differences of the number of soil microbial and enzymes activities of different species indicated that the different bush, shrub-soil had a complementary, to create a number of different areas of mixed shrubs, mixed-shrub can be more good to improve the conditions of soil fertility in the sandy land.