| Hills are widely distributed over the middle and lower reaches of Changjiang River in our country.There are many problems in this region--the shortage of the forest area, the reduction of ecological function,soil erosion,outbreak of diseases and difficulties in the protection of rare and endangered species of plants.Thus,how to recover the deteriorated forest,improve the forest structure and select efficient rehabilitation pattern, it has been becoming an important strategic and practical problem.In order to study the feature of six typical degenerated vegetations,and the ecological benefit of three vegetation rehabilitation patterns in the Xishui county,a resersch has been carried out and some conclutions have been obtained as follow:1.The exterior feature of the deteriorated community was the reduction of the layers. There was no arbor layer in the wasteland and shrubbery.The canopy density and the rate of plant coverage were declined.The canopy density was 0 in the wasteland and rate of plant coverage wasonly 60%.2.With the degenarated of the vegetation,the trend of Shannon-Wiener index was "less-more-less",and the trend of Simpson index was "more-less-more".In the paper,the Shannon-Wiener index of Lithocarpus forest was 1.4276,the Simpson index was 0.6615. The Shannon-Wiener index of less degenerated forest Mao bamboo was 2.097,the Simpson index was 0.8425.The Shannon-Wiener index of most degenerated forest wasteland was 1.3288,the Simpson index was 1.2534.3.The more degenerated a stand was,the worse of structure and ecological function it was.The soil bulk gravities of Lithocarpus forest and Cunninghamia lanceolata were 1.33g·cm-3,1.36 g·cm-3 which were less than the dates of wasteland and shrubbery 1.43 g·cm-3,1.41g·cm-3.The Pinus massoninana forest was of the best soil porosity,followed by shrubbery,Lithocarpus forest.The wasteland was of the worst soil porosity.As the same of the soil porosity trend,the soil moisture and the soil water-holding capacity also showed that the Pinus massoninana forest was best,followed by shrubbery,the wasteland was the worst.4.The degeneration of vegetation also influenced the soil nutrients.In this research, the contents of organic matter and total nitrogen in the wasteland were the least of the six plots(organic matter:0.97%,total nitrogen:0.06%),While the content of total phosphorus and total potassium was no change.5.The trendency of soil bulk gravity was wasteland＞farmland＞Pinus massoninana forest＞Amygdalus persica×Hemerocallis middendorffii forest.The bulk gravity of 0～20cm soil layer was less than that of the 20～40cm layer in all kinds of forest.The result tested that:a forest can improve the physical property of the soil.This capability was relative to the structure of a forest.6.The forest could improve the soil porosity better than that of the wasteland.The soil porosity in 0～20cm soil layer was better than that of in 20～40cm layer.The tendency of soil porosity was Pinus massoninana forest＞Amygdalus persica×Hemerocallis middendorffii forest＞farmland＞wasteland.7.The soil moisture's tendency was the same of the soil porosity.Pinus massoninana forest＞Amygdalus persica×Hemerocallis middendorffii forest＞farmland＞wasteland. Also,the soil moisture in 0～20cm soil layer is better than that of in 20～40cm layer except for Pinus massoninana forest whose soil water-holding capacity in 20～40cm was better than that of in 0-20cm layer.8.The content of nutrient was change widely in the four patterns,especially the organic matter and total nitrogen.The tendency in organic matter was Pinus rnassoninana forest＞farmland＞Amygdalus persica×Hemerocallis middendorffii forest＞wasteland. The tendency in total nitrogen was farmland＞Pinus massoninana forest＞Amygdalus persica×Hemerocallis middendorffii forest＞wasteland.9.The changes of soil porosity and moisture in different forests in different seasons was:Sep.＞Jun.＞Mar.＞Dec.10.The initial permeability and the stable permeability of Pinus massoninana forest were the most of the four forests,while the Amygdalus persica×Hemerocallis middendorffii forest were the least.11.The surface runoff after raining of rehabilitation patterns could be cut down 13%～34%contrasting to wasteland,and the quantity of soil erosion could be cut down51%～87%.The soil erosion of Pinus massoninana forest could be cut down the most.
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