Study On Main Forest Communities Structure And Their Soil Properties In The Source Of Jialing River

Using eight different forest communities (Quercus aliena BI.var.acuteserrate, Betula albo-sinensis, Pinus tabulaeformis, Pinus armandii, Abies fargesii, coniferous and broad-leaved mixed forest, shrub forest, meadow)in the source of Jialing river of as object, this paper investigated plant community characteristic in sample area, calculated species diversity, analyzed soil pH value, the content of organic matter and main nutrient at the different levels of soil under different communities, studied on soil fertility of different communities, correlations between the indices of soil nutrient, correlations between species diversity and soil nutrient. The results showed that:The main forest communities in study area are Quercus aliena, Betula albo-sinensis, Pinus tabulaeformis, Pinus armandii, Abies fargesii, mixed with a few other types, such as Populus davidiana, TiliatuanSzysz tuan, Toxicodendron vernicifluum, D.japonica var.chinensis, Carya cathayensis. The main shrub types are Euonymus alatus, Rubus corchorifolius, Lonicera japonica, Rosa multiflora, Spiraea salicifolia, Corylus chinensis. The main herbal types are Carex rigescens, Roegneria kamoji, Saussurea , Rubia cordifolia.The diversity index (Margalef species richness index, Shannon-Wiener diversity index, Simpson dominance index, Pielou evenness index) of different communities was correlated with coenotype. Margalef species richness index of each community land showed a consistent trend: herbal layer>shrub layer>tree layer. Shannon-Wiener diversity index, Simpson dominance index, Pielou evenness index of different communities do not had a consistent trend among three layers. The diversity index became much higher with more complexity of community structure, more richness of species in three layers, weak dominant species and more mixed species.The soil in Pinus armandii, Pinus tabulaeformis and coniferous and broad-leaved mixed forest were near neutral, the soil in Quercus aliena, Betula albo-sinensis, shrub forest and meadow were slightly acidic, the soil in Abies fargesii was acidic. The soil pH value, the contents of soil organic matter, total N and P, alkali-hydro N and available P tended to decrease with soil depth. The soil fertility was decreased in the order of Betula albo-sinensis >meadow >Abies fargesii>shrub forest> Quercus aliena >coniferous and broad-leaved mixed forest >Pinus tabulaeformis >Pinus armandii.According to analysis of correlations between the indices of soil nutrient, soil pH was significantly negative correlated with the contents of soil organic matter; the contents of soil organic matter was highly significantly correlated with soil total N and P, alkali-hydro N. There were significantly correlation between soil total N and alkali-hydro N, total P and available P.According to analysis of correlations between species diversity and soil nutrient, Margalef species richness index was significantly correlated with soil organic matter. Shannon-Wiener diversity index was significantly correlated with soil total N and P. Simpson dominance index was significantly correlated with soil total N and P. Pielou evenness index was significantly correlated with soil organic matter and soil total N. All indices of species diversity were negative correlated with soil nutrient, but the relative coefficients were small.