Ecological Benefits Of Different Land-use In Karst Area

Karst widely distributes in Southwest China. The natural factors and human factors result in karst rocky desertification. For the purpose of ecological restoration and reconstruction, a series of measures are taken and they achieved different results. The evaluation of eco-efficiency is particularly prevalent in returning farmland to forest (grassland). The rocky desertification area is less, the common methods of Eco-efficiency evaluation are fuzzy evaluation method, AHP, and the Gray Relation Projection method. The study area is located in Nanchuan Nanping.rocky desertification becomes a constraining factor of economic and social development. For bringing rocky desertification under control and improving the local ecological environment, returning farmland to forest, terracing, planting herbs, etc as the measure are taken. Analysis of the restoration measures can better guide the local rocky desertification area to restore and promote the local ecological economic and social to be harmony.The representative recovery mode in this area is honeysuckle, camphor, pine, terracing farmland, and abandoned land as the compared.The altitude gradient of every mode is similar. From 6:00 to18:00, active photosynthetic radiation, temperature, relative humidity, and soil temperature of each mode are recorded. The soil samples are gathered for the determination of physical and chemical properties.Micro-climate benefits:the different vegetation types vary photosynthetic active radiation, the intensity of shading effect between different vegetation is returning farmland to forests (camphor, pine), terracing (farmland), Chinese herbal plant (Lonicera japonica), abandoned land. For the regulation of relative humidity, the relative humidity of the same pattern gradually weakened with height increasing. Abandoned land is lower than the other modes. Daily temperature range of the abandoned land is larger than any others on each level. Overall, the order of daily soil temperature is returning farmland to forest, terracing, Chinese herb. The average soil temperature range of them is less than the abandoned land. The recovery model increase vegetation cover and reduce the diurnal soil temperature. The soil structure and water content are improved. This is good for physical and chemical processes of vegetation. By comparing the soil and water conservation benefits of every mode, we can see, organic matter content of farmland, honeysuckle, camphor forest and pine forest is more than abandoned Camphor forest and pine forest organic matter content is higher than honeysuckle. It is due to the longer resuming time, the higher degree of surface vegetation and the surface litter decomposition. The highest is farmland, as opposed to abandoned land, the farmland, honeysuckle, camphor forest, pine all improve the degree of nitrogen content of surface soil. The level of soil available K follows agricultural land, honeysuckle, camphor, pine, abandoned land, which is same as available phosphorus content order.For research purposes, the photosynthetic active radiation, temperature, relative humidity and soil temperature selected on micro-climate benefits, soil bulk density, soil organic matter, total nitrogen, available phosphorus, available potassium selected on soil and water conservation can build Gray Relation Projection evaluation index system. According to Gray Relation Projection evaluation methods, first of all is setting the optimal program, building matrix. The final projection is getting value of the recovery mode. The eco-efficiency of other recovery model are better than the abandoned land. The farmland is largest. This is due to the artificial application of organic manure and chemical fertilizer for agricultural crops, increasing in soil organic matter and N, P, K content. Thereby it affects the value of projection. Overall, all the recovery mode of Rocky desertification area are beneficial to the ecological environment improvement and sustainable development.