Study On The Undergrowth Vegetation And Soil Fertility Of The Typical Forest In Changsha Suburb

Undergrowth vegetation is an important component of the ecological system. Undergrowth vegetationwhich plays a very important role in accumulating and circulating nutrient elements of the forest ecosystem, maintaining the biodiversity of forest and the soil fertility, conserving water and soil, protecting environmental, and the development of forest succession et al. Based on combining the filed investigation and laboratory analysis methods, the community characteristics and soil physical and chemical properties of the forest management area of Hunan Academy of Forestry in ChangSha suburb were investigated and analyzed. The study included the genera, biodiversity, biomass of the undergrowth vegetation and the distribution and accumulation of soil nutrient. Furthermore, the relationship between the species diversity, biomass of undergrowth vegetation and soil nutrient were studied. It provided a theoretical basis for the vegetation restoration of the existing vegetation, the analysis showed that:1. In sample area, there are 25 familiars,36 genus and 44 different species, including 33 species woody plants, while 11 species herbs. The number of undergrowth vegetation in Cunminghamia lanceolata forest, Cinnamomum camphora forest and Liquidambar formosana forest was very close and significantly more than Pinus elliottii forest.2. Seven indexes including the species richness, diversity and evenness were analyzed:in distributing vertically, the species enriches and diversity index one degree of bush layer>herb layer, while evenness index was not one degree in different forest. The ecological dominance index showed bush layer>herb layer, except Pinus elliottii forest.3. The order of live undergrowth vegetation biomass showed:over ground> underground. In the litter biomass, the percent of H layer was the biggest and broad-leaved forests were more than coniferous forests. The order of total biomass in undergrowth vegetation was:Pinus elliottii forest> Cunminghamia lanceolata forest>Liquidambar formosana forest>Cinnamomum camphora forest. The order of live undergrowth vegetation biomass was:Pinus elliottii forest>Liquidambar formosana for est> Cunminghamia lanceolata forest>Cinnamomum camphora forest. The order of the litter biomass was:Pinus elliottii forest>Cunminghamia lanceolata forest>Cinnamomum camphora forest>Liquidambar formosana forest.4. The vertical differentiation law of soil physical properties and chemical properties were obvious. The soil bulk density differences in different soil layers of same stand was not obvious, and the bulk density essentially increases with soil depth, while capillary porosity, total porosity and natural water content basically reduced with soil depth. Chemical nature in different forests basically decreased with soil depth. Based on separate content analysis of total N and available N, total P and available P, total K and available K in four forests of the pilot area, all the results showed significant positive correlation.5. Undergrowth vegetation species diversity index has a positive correlation with soil total P, and has a basically positive correlation with soil water content, soil organic matter; but all kinds of forest undergrowth vegetation species diversity has not significantly relation with soil bulk density, soil non-capillary porosity, pH, N, K. Each diversity index had a linear correlation with total N, total P and available P.6. In four kinds forests, undergrowth vegetation biomass has no remarkable correlation with the soil volume weight, soil no capillary porosity and pH; the shrub layer biomass has remarkable positively correlation with soil moisture content and organic matter. The herb layer biomass is significantly related to total P, available P and available K; the litter biomass has remarkable positively correlation with soil organic matter, and has a significant positively correlation with N.