| In this paper, the typical plant configuration modes of returning farmland to forests in Liping County, Guizhou province was chosen to be the study objects. Through the method of field investigation laboratory analysis, and the quantitative calculation combined with qualitative analysis, the paper did some individual studies to the species diversity, the plant biomass, the physical and chemical properties of soil as well as woodland hydrological characteristic analysis, and then conducted a comprehensive evaluation of ecological benefits by using the method of market substitute.Since returning farmland to forest in Liping County, At the end of2009, the new forest area promoted by cropland to forest project is14340.5hm2, and the forest cover increased3%; The soil erosion modulus declined from1265.4t/km2·a to4734t/km2·a in the area of the project. The herbaceous species under the different configuration modes is vegetation-rich but significantly different. The role Cunninghamia Lanceolata played in aspect of promoting forest species diversity is significantly. The species diversity under the modes of Quercus mixed with Alnus cremastogyne and Alnus cremastogyne mixed with Toona sinensis were relatively better than some individual forest mode. The biomass of tree and shrub layer, herb layer and litter in all converting types accumulated and increased but different with the yeas of returning forest to farmland increased. The biomass of Cunninghamia Lanceolata is maximum, the understory herbaceous biomass under most types of converting land are greater than natural grassland. The litter accumulated under the woodland effectively reduced the water erosion and enhanced soil corrosion resistance.The soil of reforestation of the cultivated land is looser than farmland, so aeration is improved and soil storage capacity increased, then a good plant-soil loop structure formed. The stereo composite structure of tree, shrub and grass because that returning farmland to forest is favorable for rainfall spatial-temporal distribution, thus played the role of soil and water conservation. Though intercepting rainfall and adjusting water infiltration effects vary for different trees, herbaceous and litter, they all reflected the forest hydrological functions and achieved the goals of soil and water conservation.By methods of market substitution, the result indicates that the total eco-efficiency value of the cultivated land in Liping County is6,601,555,100Yuan including water resources protection value which is2,211,481,200Yuan, soil conservation value which is15,772,300Yuan, carbon dioxide fixed and oxygen output value which is4,150,227,100Yuan, environment purification value which is2994thousand Yuan, biodiversity protection value which is137.4177million Yuan, and microclimate improvement value which is83,662,800Yuan. |
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