Study On Ecological-Agriculture Models For Rehabilitaion In The Rocky Desertification Area Of Guangxi

Guangxi is one of the typical karst regions in the world, which 79 counties are confronted with rocky desertification. The peak-depressions region of erosion-corrosion types in Northwest Guangxi is the most adverse in natural condition and the most vulnerable ecological environment. Some eco-agricultural developing models were introduced for rehabilitation in the desertification regions in the past five years, which has shown an effective ways. Basing on the existing studies, three demonstration site including Sanzhiyang, Duan county, Guzhou, Huanjiang county and Longhe, Pingguo county were selected for research in this paper, where it has been considered serious rocky desertification in environment and poverty in social and economy. Investigation and data were collected in the three sites, which is applied in the qualitative and quantitative methods to conduct analysis and evaluation on the eco-agricultural developmental model.Considering the fact of this rocky desertification region, 18 indexes were chosen for evaluation model system establishment. They are from the consults of specialists, and then converted by AHP to determine the weightiness. The results showed that weightiness for ecological system, economical system and social system were 0.3745, 0.3504 and 0.2751 respectively. Among various evaluation indexes, the biggest weightiness is vegetation coverage, reaching to 0.0878, followed by 0.0702 of farmer's skill, 0.0675 of net income per capita, 0.0673 of the basic education level, 0.0659 of output/investment ratio and 0.0654 of the labor work efficiency.The field and social and economic data of 2000 and 2006 were monitored and collected from three demonstration sites, for static and dynamic state analysis. The results showed that, the values of integrated evaluation index of static state for the complex effects of eco-agriculture in Sanzhiyang, Guzhou and Longhe were 0.6446, 0.6424 and 0.6138 respectively, indicating that they fit in middle level eco-agricultural development. The values of integrated evaluation index of dynamic state for the complex effects of eco-agriculture in these 3 sites were 0.3705, 0.4536 and 0.3250, suggesting the change condition of the system is stable maintainability and rapid development. In 2006 year, the first three biggest weightiness indexes (the vegetation coverage, the farmer skill and the net income per capita) in the evaluation system had considerable increase than those in 2000 year, which had greatly contributed for promoting eco-agriculture's complex effects.However, the intensity of adopting pesticides, the intensity of using chemical fertilizer and the cultivated area ratio of slope over 25°formed negative influences on the complex effects of eco-agriculture system. In all three systems, these 3 indexes are low. Therefore, in the process of developing eco-agriculture, it is necessary to apply less pesticides and chemical fertilizer, particularly to avoid virulent pesticides, and it is necessary to advocate the application of biological pesticides, organic fertilizer and biological fertilizer and spread the techniques of biological control. The polity of "to substitute the farming by the afforestation" should be developed and the ratio of cultivated area with steep slope should be decreased.The results of this research would be a reference for the ecological rehabilitation to promote the agricultural production in the rock desertification area of Guangxi, and would have important significance for raising the ecological and social development level of the people in the karst area as well.