Study On Soil Ecological Function Of Water Conservation Forests And Selection Of Optimal Afforest Models In HuangPu Jiang River Basin

The thesis studies the soil ecological function of water conservation forests and discusses the optimal afforest models in HuangPu jiang River Basin, the results are described as follows: (1)Organic matter content, total nitrogen content, available phosphorus and potassium content reduce obviously with depth of the soil in each plot, but PH value increase obviously on the contrary. (2)The plots can be divided three kinds by the average distance clustering analysis according to soil fertility conditions, the difference of the soil conditions among the plots indicates that forests improve the soil condition and the older forests make the better effect. (3)Soil moist content and porosity reduce with the depth of the soil and they are different obviously with the kind and the age of forests .The max water conservation capacity varies between 265.64mm and 380.58mm and the available conservation capacity varies does between 8.05mm and 32.05mm within 0.6m soil. It indicates that forest can improve the soil physical properties and conserve water greatly. The main factors that effect water conservation capacity are porosity, organic matter content and bulk density. (4)Soil infiltration rate are different obviously among the plots. The older forests make the better effect. The process of soil infiltration accords with the logarithm curve. Bulk density, organic matter content and porosity are the main factors which effect the soil infiltration greatly by analyzing the relationship between the infiltration rate and main physical and chemical properties, but the soil texture has a little effect on the soil infiltration. The relationship model between the infiltration rate and main physical and chemical properties can be established by the stepwise regress. (5)Based on the general ecological area partition and the stand quality assessment and adjusting measures to local condition with the principle of ecological properties and economical construction, the proper afforest trees (arbor, shrub, grass) are selected for the HungPu jiang River Basin. The afforest models for each area are designed according to the ecological properties of the tree, landscape optimization and the environmental function sanity. Three to five various test demonstrating areas of water conservation forests (ecology type, ecology economy type, landscape ecology type, marsh environment protection type) are established, each type consists of three to five models and each model consists of thee to four main kinds of trees. The pure and mixing afforest matters are used for the spatial structure. The investigation indicates that all the models grow well and produce good result.