The Influence Of Enclosing On Soil And Vegetation On The Degradation Grassland In Duolun

We used vegetation bionomics, resume bionomics and agrology to study the degradation grassland in the Duolun County, and researched the influence of enclosing on soil physical and chemical properties and vegetation characters by fieldwork, experiments and analyzing data. The main conclusions are as follow:Enclosing can improve the soil physical properties effectively. As inclosing time increasing, soil physical clay content, soil porosity, saturation moisture retent and the water content of topsoil increase markedly. But the water content of deepsoil and bulk volume decreases gradually. As the inconclosing time'increasing, the pH and available potassium of soil decrease gradually. The organic matter, total nitrogen,available phosphorus,the total Phosphorus and total Potassium increase have an opposite result, available nitrogen rises a little. The topsoil'change are obvious and the deposal'are not. Except the soil pH, the changes of other soil chemical index have close relation with the enclosing time. It shows that enclosing can improve the soil's development.Enclosing can renew the degradation grassland rapidly. The vegetation coverage, grass height and biomass of the classical grassland in inclosure increased remarkably at the early stage. The vegetation coverage and biomass are the biggest after 5 years'inclosing. But the longer the time of enclosing is, the increase degree begins to decrease. Inclosing has no marked effect on species composition, population density and spatial pattern. Considering the ecological and economic benefit, 5 years is the best enclosing period in Duolun.