| Energy demand in the developed countries and developing countries has increased dramatically In recent years. Bioenergy will play a more important role in the future energy system. It can alleviate the greenhouse effect to some extent, guarantee the energy security, at the same time bring economic and ecological benefits. Energy plants usually refers to those plants which are of high energy use efficiency, have higher ability of reducing hydrocarbon synthesis, can produce products that are close to the oil and alternative oil, also rich of fat, sugar, starch, cellulose. Wheat, corn and other food crops can be used as an energy plant, however, it is against with the principle of "not to reclaim land and food, not compete for food with people". Elephant grass, as a new generation of biomass energy resources, not to reclaim land and food, not compete for food with people is in the stage of rapid development. There are a lot of marginal land in China which is not suitable for food crops. But it is suitable for those energy plants with strong environment appropriate ability.This study is based on the data of land use in2008、DEM data、soil data、 meteorological data, etc. According to temperature, moisture content, slope and soil environment requirements that various energy crops need to grow, based on ArcGIS platform, adopting the method of multifactor comprehensive evaluation, the SWOT analysis to analyze marginal distribution, suitability level of land resources in our country as well as the appropriate marginal land area, discuss marginal land use strategy, put forward marginal land utilization countermeasures in accordance with resource saving and environment-friendly society building requirements. Main results and conclusions are as follows:1. The concept of marginal land is defined. Marginal land refers to the natural condition is poor, neglected woodland (open woodland, shrub woodland and other woodland), grass (high coverage grassland, medium coverage grass, low coverage grassland), unused land in fragile ecological environment area. These lands are distributed scattered, difficult to use, but is suitable for energy plants cultivation whose environmental requirements is not high.2. On the basis of suitability evaluation of Pennisetum Purpureum, with annual average temperature, effective soil layer thickness, water, surface gradient, soil texture, altitude six factors as evaluation indexes, using ArcGIS for comprehensive analysis and evaluation, the suitability of Pennisetum Purpureum is divided into three levels, the most suitable, basic suitable and unsuitable. Thereby get the type distribution of marginal land use and the total number of marginal land suitable for hair elephant grass, the most appropriate number and basic suitable quantity.3. Marginal land development strategy is elicited based on the SWOT analysis of elephant grass. Marginal land utilization should play all sorts of advantage, overcome weaknesses, seize the opportunity and defuse threat from all sides.4. Suggest popularizing the knowledge of rural biomass energy, giving full.play to the role of private investment, meanwhile, the government should increase investment and scientific research strength, tilt is given from the funds to biomass energy high technology and new technology enterprise. Build "company+farmer cooperative economic organization+peasant household" mode of marginal land development and utilization, to coordinate the power of all aspects, solve problems step-by-step and specifically, overcome shortcomings, and jointly promote the development of biomass energy industry in China. |
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