Evaluative Feature Of Microbial Population And Enzyme Activity Under Plant Restored Process In Loess Regions

Conceding the land to forest (grass) was a fundamental policy in China. It is most important to improve the ecological environment in the north of Shannxi province. The soil biochemical properties (including to soil microorganism, enzyme and particular microbiological groups) made up one of three main components in soil. they played very important role in the cycles of nutrient substance, improvement of soil fertility and remediation of pollutant. But there were seldom systematic researches about combination in China and even abroad. Therefore, this study has important theory value and practical significance.This paper commenced on National Loess Plateau Ecology laboratory in Ansai, concerned on soil fertility, soil microorganism, soil microbiological physiological groups and soil enzyme activity of different time and vegetation restoration. The change of soil micro-flora and the evolution of soil microbial activity in the Process of Ecosystem Restoration in Loess Hilly-gully Region were studied. The correlation analyses between soil microbial population and soil fertility was researched in orde 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 the Returning Farmland into Forest and Grassland scientifically and objectively.The results showed that Soil Physical and Chemical Properties were improved notably after natural rehabilitation in erosion environmental slope farmland, among which Sophora viciifolia was the most effective plant. There was significant positive correlation between soil physic-chemical properties and rehabilitation times. The mixed shrubs and Sophora viciifolia increased soil microorganism and soil enzyme activity evidently. As time went on, the microorganism increased. The variational regularities of soil enzyme activity were different. But the total regularity was increasing. A part of soil microorganism and microbial physiological groups population increased after fallow.Soil fertility and soil microbial population improved notably after the Robinia pseudoacacia, Caragana korshinskii, Hippophae rhamnaides were planted. Apple orchard rehabilitation in erosion environmental slope farmland showed the same result. Compared with the site of control, the increasing range of Soil Physical and Chemical Properties were 5%-340%. Hippophae rhamnaides has the best effect. Generally the soil properties improved continuously with the time going on. The Effect of Soil Amelioration of R.pseudoacacia-A.fruticosa, P.tabulaeformis-Amorpha fruticosa and fallow land were better than pure forest. The regularity of Soil Physical and Chemical Properties were not distinct after artificial. Apple orchard. Possibly because of the apple bumper and poor harvest.The soil urease and phosphatase activities of Robinia pseudoacacia and Apple orchard were increased obviously while the soil urease, phosphatase and sucrase activities of Hippophae rhamnaides increased obviously with the time going on, too.The soil organic matter, total N, available K, phosphatase and invertase activity in the grazing reached the highest level under different cultivated land use types. The content of soil total p, available p and available N in the plain terra were the highest. Soil fertility and enzyme activity sequence was Quercus liaotungensis >Mixed shrubs >Platycladus orientalis >Sophora davidii under different Natural Forest types. It revealed that the soil quality be improved mostly in Quercus liaotungensis and soil microbial population could be improved notably under different cultivated land and natural forest use types.Correlation analyses showed that the correlation between soil physic-chemical Properties, microbial population and enzyme activities were distinct under different soil conditions. It indicated that the ecological system was extremely complex because of the multiple factors; a thorough study should be made future.Principal component analysis (PCA) was an important mathematic analytic method. The PCA of microbial population, enzyme activities and soil Physic-chemical properties had done under different soil conditions, showed PCA can be better explain soil enzyme activity affected by different vegetation restoration patterns. It also revealed the differences of restoration under different plant-life and vegetation types. The soil microbial population and enzyme activities could basically reflected the deviance of soil information system. It proved the importance of soil microbial population and enzyme activities once again and their feasibility and reliability of using as evaluation indexes in vegetation ecological restoration.