| The karst area of southwest China centers on Guizhou plateau, which is the largest in area and most vulnerable ecological environment area in world’s three largest karst contiguous area. The area in Guizhou rocky desertification is the first in every province of China and the degree is the most serious. To solve the problem of rocky desertification is one of the most urgent tasks in southwest karst mountain area. The problem of desertification is composed of two aspects mainly, one is the ecological environment and the two is the social economy. The appearance of desertification problem is mainly due to people develop ecological environment blindly and unreasonably under backward economy, which cause ecological environment worsened and hinder economic and social development ultimately. Agricultural grass and vegetation project is one of the best ways to restore the rocky desertification ecological environment and develop society economy.This study selected two typical karst rocky desertification form-- karst plateau mountain and karst plateau valley to establish demonstration area. Bijie Salaxi Demonstration Area is a typical representative of mild moderate rocky desertification environment as karst plateau mountain while Guanling-Zhenfeng Huajiang Demonstration Area is a typical representative of moderate intensity rocky desertification as karst plateau valley. Taking relevant theoretical principles like the natural geography, ecology, soil and water conservation, ecological economic, the system coupling, ecological breeding, pratacultural science etc. as the theoretical support. Through experimental study in the demonstration area of agricultural grass and vegetation construction, compacting the key technology, forming demonstration mode, finally summarizing the benefits of monitoring, integrating and promoting.The essence of agricultural grass and vegetation optimization configuration technology is vertical zonality theory. Studying the optimization configuration technology on agricultural grass and vegetation y of the rocky desertification area, the essence is taking small watershed as a unit of the micro spatial scale, studying how agricultural grass and vegetation make full use of light, heat, water, soil and other natural resources, then realize the governance of rocky desertification. Through carrying out agricultural grass and forest planting under small watersheds of different spatial scales, in accordance with the basic principle as " Farming if suitable for farming, forestation if suitable for forest, grass if suitable for grass", conducting the construction of spatial allocation of agricultural grass forest project.The grade and potential index of rocky desertification are important indicators for space layout of agricultural straw project. With the condition of that in the bottom of peak cluster depression and the plateau valley, the low rocky desertification grade, thick soil, difficulting in happening water and soil loss, combing with specific circumstances to carry out the economy oriented govern model of “ crop and grass”, “economic forest and herbage” for rocky desertification; From the real situation, conducting ecological restoration oriented management model of " protection forest and herbage", “ herbage and crop” for rocky desertification under the area of high grade, incident water and soil loss, steep slope and high potential index of rocky desertification. The vertical zonality of Huajiang Demonstration Area is obvious and the degree of differentiation of spatial configuration is higher than that of Bijie Demonstration Zone.Ecological restoration and economic development oriented are the two modes of agricultural straw and spatial optimization in rocky desertification control. Ecological oriented agricultural grass vegetation spatial optimization allocation model, under the condition of potential rocky desertification index greater than 5, mainly on ecological restoration and economic development as supplement. In this mode, the ecological environment is very fragile and can easily lead to the occurrence and aggravation of rocky desertification. Whether agricultural-grass or forest-grass project must be focused on the control of desertification, with the development of forest-grassland animal husbandry and economic forest. As the premise of farmers’ willingness in planting crops is hard to change, low density of crop planting in order to harvest forage grass is better. Economic oriented agricultural grass vegetation spatial optimization allocation model, is the condition of potential rocky desertification index less than 5, use advantage resources to develop the economy oriented characteristics of mixed farming and forestry and animal husbandry on the basis of rocky desertification has been effectively improved. This model can develop economy and control rocky desertification at the same time, finally format economic and social development form such as the characteristic fruit industry, grassland ecological animal husbandry industry, agricultural product commercialization etc.Pasture is the material basis for rocky desertification control project of agricultural grass and vegetation measures, and an important part of the ecological restoration and the improvement of soil and water conservation efficiency. The photosynthetic experiments of economic forest and grass in Bijie Demonstration Zone show that: The middle-aged net photosynthetic rate of Legume is the highest in Medicago sativa, the next are Trrifolium repens and Trifolium pratense. Water use efficiency of Trrifolium repens Medicago sativa and Trifolium pratense are the highest. Among the gramineous plants, Festuca elata in the net photosynthesis grasses have the highest photosynthetic rate, the next is Bromus cartharticus. Lolium and Dactylis glomerata. The Dactylis glomerata and Lolium have the highest water use efficiency, the next is Festuca elata. Alexeev and Dactylis glomerata. Through the Trrifolium repens+Lolium unicast and mixed sowing tests, showing that mixed sown pasture treatment can improve the net photosynthetic rate and water use efficiency. The net photosynthetic rate of annual difference of Walnut and Rosa roxburghii is not obvious, but the Walnut have higher water use efficiency. The Stylosanthes guianensias net photosynthetic rate and water use efficiency are higher than Medicago sativa. In Hua Jiang demonstration area. The net photosynthetic rate and water use efficiency of Zanthoxylum bungeanum. In the group of Zanthoxylum bungeanum. forest+Medicago sativa is higher than merely Zanthoxylum bungeanum forest.The Key Technology of spatial optimal allocation of agricultural-grass and forest-grass. According to the Rocky Desertification in Bijie karst mountainous plateau, combined with the natural and social economic background, carrying out ecological restoration-led the key technology of optimizing configuration of agricultural grass, economic development-led the key technology of optimizing configuration of agricultural grass, and economic development-led the key technology of optimizing configuration of unique forest grass. Through the crop and economic forest intercropping forage livestock breeding, forming mode of ecological restoration of mixed farming in the rocky desertification control of economic development. According to the Rocky Desertification in Huajiang karst Valley, combined with the local natural and economical background, and potential index of rocky desertification development, to carry out ecological restoration-led the key technology of optimizing configuration of forest grass, ecological restoration-led technology of optimizing configuration of agricultural grass, economic-led technology of optimizing configuration of agricultural grass, economic development-led the key technology of optimizing configuration of unique forest grass, ecological restoration-led the key technology of optimizing configuration of forest grass, and livestock and poultry breeding technology in courtyard. Through using vertical differences in the dry-hot valley, develop characteristic economic forest, improve “pig-biogas-pepper” through forest crop intercropping forage, and form distinctive model of “pig-biogas- pepper-grass”, realizing the control of rocky desertification and economic development.Monitoring and Evaluation of spatial optimal allocation of agricultural-grass and forest-grass. Through ecological monitoring of optimizing configuration of grass between Bijie and Huajiang demonstration area, in unit time, the growth height and diameter at breast height of Juglans regia, Rosa roxburghii and Chinese prickly ash in forest and grass intercropping mode are higher than economic forest; economic forest and crop diseases and insect pests occurrence and wild weed invasion probability in forest and agricultural grass intercropping mode are lower than economic forest and maize monoculture. Vegetation coverage in the mode of agricultural and forest grass is significantly higher than pure forest and crop monoculture. Through the monitoring of social economic benefits, two model of optimizing configuration of grass in rocky desertification control can not only increase crop output per unit area, but also increase the yield and quality of fruit, increase economic efficiency.Using the raster data spatial analysis method, through ARCGIS spatial analysis, the model promotion of demonstration zone were evaluated aptly. The comprehensive promotion suitability on mixed agricultural and forest grass compound management mode of Salaxi in South China karst distribution range shows, the most suitable area for promotion is 19.97 million km2, accounting for 10.31% of the land area; the more appropriate area for promotion is 42.64 million km2, accounting for 22.02% of land area while suitable area basically for 50.78 million km2 and accounting for 26.22% of the land area. The promotion suitability on the mixed mode of agricultural and forest and ecological farming garden of Huajiang in South China karst distribution range shows, the most suitable area for promotion is 27.05 million km2, accounting for 27.09% of land area, the more appropriate area of promotion is 45.29 million km2, accounting for 23.39% of the land area while basic suitable promotion area for 55.19 million km2 and 28.48% of the land area. |
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