| The Three Gorges Project is paid attention in the worldwide, and the ecological environment problems in reservoir area especially in hydro-fluctuation belt is the most important aspect. Changes in the Three Gorges reservoir water level is regulated by the scheduling, and periodic appeared alternating in hydro-fluctuation belt. is caused by water level fluctuations. During the changing progress, the soil in hydro-fluctuation belt is effected not only by gravitational erosion and water wave impact which is caused by fluctuation of water level, but also by rainfall erosion. The long and continuously influence will cause the altering of soil, and most of the terrestrial plants in hydro-fluctuation belt which can not change their biological and ecological habit will get survival crisis. In order to reduce even eliminate the ecological environment problems in hydro-fluctuation belt, based on the fact in Three Gorges reservoir hydro-fluctuation belt, according to water level in hydro-fluctuation belt, local conditions, choosing suitable plants, structure configuration scientifically, developing restoration and reconstruction, which are important goals in making full use of resource in Three Gorges reservoir hydro-fluctuation belt, improving the ecological environment condition and promoting economic and social sustainable development in reservoir ares. Revealing temporal dynamic change law and development trend of soil physical and chemical properties and vegetations in hydro-fluctuation belt after reservoir is the most key problem. This research is based on located monitoring of soil physical and chemical properties and vegetations in Zigui and Wushan hydro-fluctuation belt in the past three years. The result shows that:(1) The Three Gorges area of the hydro-fluctuation belt was affected by water level fluctuations, soil physical properties have changed a lot. In hydro-fluctuation belt 156-172 m above sea level section, different layers after 1 year of water level fluctuating, soil density increased 2.69-16.72%, total porosity decreased 1.73-16.25%, capillary porosity deceased 7.09-22.82%, non-capillary porosity decreased 16.26-48.21%, maximum moisture capacity decreased 2.79-14.66%, capillary moisture capacity decreased 9.31-15.87%, field capacity decreased 5.05-22.71%,and in the layer of 0-10cm, thick sand content increased by 29.43% and the fine sand, silly sand and clay content decreased by 9.17%,10.94% and 17.60% separately.In hydro-fluctuation belt 145-156 m above sea level section, different layers after 3 years of water level fluctuating, soil density increased 3.58-8.48%, total porosity decreased 3.59-20.20%, capillary porosity deceased 5.05-22.65%, non-capillary porosity decreased 12.19-41.60%, maximum moisture capacity decreased 4.63-26.29%, capillary moisture capacity decreased 2.61-28.64%, field capacity decreased 3.30-25.49%, and in the layer of 0-10 cm, thick sand content increased by 47.10% and the fine sand, silly sand and clay content decreased by25.37%,64.83% and 43.88% separately. The variance analysis showed that the effect of water level fluctuating is most significant in the layer of 0-10 cm,(2) The result shows that: the By the influence of water level fluctuating, soil nutrient had reduced in hydro-fluctuation belt generally, but the drawdown speed of each testing index were different.In hydro-fluctuation belt 156-172 m above sea level section, different layers after 1 year of water level fluctuating, available N decreased by 41.53 -59.87%, available P decreased by 5.34-36.57%, available K decreased by 3.55-45.46%, total N decreased by 5.75-40.11%, total P had no change generally, total K had decreased a little, content of organic material decreased by 12.15-37.83%, pH value turned to neutral, changed by 1.82-9.53%. Compared with the non-submerged zones, after one year of water level fluctuating, the difference of available N and organic material, was significant at 0.05 level.In hydro-fluctuation belt 145-156 m above sea level section, different layers after 3 years of water level fluctuating,, available N decreased by 34.6 -59.63%%, available P decreased by 30.97-70.32%, available K decreased by 6.10-17.58%, total N decreased by 14.02-45.60%, total P decreased by1.34-40.13%, total K had decreased a little, content of organic material decreased by 110.82-34.43%, pH value turned to neutral, changed by 1.63-5.29%. Compared two years of water level fluctuating zones, after three years of water level fluctuating, the difference of available N, P and total N in layer 0-10 cm, was significant at 0.05 level.(3) In hydro-fluctuation belt 156-172 m above sea level section, after 1 year of water level fluctuating, the number of plant species had decreased a lot. Each monitoring plot had decreased differently by 28.3-34.55%, mean by about 34%. The life form of plant had changed o lot, herbs increased by 13.56%, shrubs decreased by 72.63%,trees decreased by 84.62%. After 1 year of water level fluctuating, importance value of plants had changed significantly The herbs which were suitable in hydro-fluctuation belt were more important. The diversified index of Shanon-winner,Sinmpson,PIE, and Pielou of herbs were all decreased.In all monitoring plots in hydro-fluctuation belt 145-156 m above sea level section, in 2007(after 1 year of water level fluctuating) appeared 114 species of plants, 2008(after 2 years of water level fluctuating) appeared 95 species of plants, 2009(after 3 years of water level fluctuating) appeared 31 species of plants. From 2007 to 2009, the species of plants had decreased by 72.81%. The most of plants were herbs till 2009. And by the increase of water level fluctuating cycle, perennial herbs had decreased, annual herbs had increased by years. The diversified index of herbs in hydro-fluctuation belt were still decreased.(4) Based on the importance value of plants in monitoring plots, preliminarily considered the following plants can be options in restoration and reconstruction in Three Gorges reservoir hydro-fluctuation belt. In hydro-fluctuation belt 156-172 m above sea level section(the shallow and middle level), the herbs are: Cyperus rotundus , Bidens tripartita, Setaria viridis, Crassocephalum crepidioides, Eclipta prostrata, Digitaria chrysoblephara, Acalypha australis ,Oxalis corniculata, Saccharum arundinaceum, Bothriospermum tenellum ,Crassocephalum Setaria, crepidioides palmifolia, Ficus tikoua, Conyza bonariensis, Pouzolzia zeylanica, Gnaphalium affine, Digitaria sanguinalis, Rubu innominatu, Artemis caruifolia, Solanum americanum, Chrysanthemum indicum, Leptochloa panicea, Carex sclerocarpa, Pteris vittata, Paspalum thunbergii. The shrubs are:Diospyros lotus, Mallotus barbatus, Vaccinium mandarinorum, Rosa laevigata, Glochidion wilsonii, Coriaria sinica, Vitex negundo, Koelreuteria bipinnata, Rhus chinensis, Discocleidion rufescens, Myrsine africana , Broussonetia papyrifera, Indigofera pseudotinctoria, Vitis pseudoreticulata. The trees are: Sapium sebiferum, Koelreuteria bipinnata. In hydro-fluctuation belt 145-156 m above sea level section(the deep level), the herbs are: Digitaria ternata, Digitaria sanguinalis, Setaria glauca, Hemarthria altissima, Cyperus rotundus, Bidens tripartita,Cyperus iria, Xanthium sibiricum, Eclipta prostrata, Hemarthria compressa, Pouzolzia zeylanica, Crassocephalum crepidioides, Conyza bonariensis, Setaria viridis, Physalis angulata, Setaria palmifolia, Echinochloa crusgalli var hispidula, Cynodon dactylon, Alternanthera philoxeroides, Arthraxon hispidus, Eleusine indica, Solanum nigrum, Youngia erythrocarpa, Amaranthus hybridus. Because of the longest under water time and the deepest water level in this area, the suitable shrubs and trees are not found yet.
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