Agro-ecological Security And Evaluation System

The rapid development of science and technology has made great contribution to the improvemeiits in life quality and social productivity for mankind since 20th century. However, many ecological problems, such as rapid population growth, natural resources depletion, environmental pollution and deterioration, have also become more and more severe at the same time, and are inhibiting further development of economy and improvement of the life quality, even menacing the existing of human life in the future. Therefore, the ecological security attracts more and more attention in the world. In China, a series of ecological problems, such as water and soil loss, shrinking and disappearing of lakes, drying of rivers, water shortage and water & air pollution, are even more severe than those in other countries because of its fragile foundation of natural ecosystems. Hunan province is one of the important parts of China's essential area for agricultural production. Agriculture in this province plays a very important role in its regional economic system. In the past 20 years, although the central government and regional governments of all levels have made great efforts in the environmental engineering for lakes, rivers, mountainous areas construction, the environmental quality of this province is still worsening. Ecological deterioration and natural disasters are still the main obstacles for the regional economic and agricultural development in this province. This dissertation, mainly based on the research project on the agricultural ecological security of Hunan province, can provide practical instructions to the maintenances of ecosystem and sustainable development of regioaal economy of Hunan province. Theoretically, it also expands the research realm of regional ecology and agricultural ecology, especially by improving the methods of quantitative evaluation of ecological security. A new concept of ecological security was defined as the state of ecosystems at different hierarchical scales and categories in certain period that can maintain its normal inaer structure and functions and can meet the needs of sustainable development of human life. Furthermore, the agricultural ecological security was defined as the healthy state of agricultural environment and ecosystem that is not polluted, destroyed or menaced. A general study was carried out to analysis the current quality of ecological environment, the main problems in the construction of ecological security and great achievements of application of ecological agricultural technologies, the extension of multi-class ecological agricultural models, the development of green industry and no harmful agricultural products of China in the past two decades in the beginning of this dissertation. Based on a detail study which concentrates on the systematic appraisal of ecological environment of Hunan province-the AOI (area of interest) of this dissertation, the main problemsmenacing the ecological security of Hunan province are given out as following: (1) too great pressure of large rural population on the environment and resources; (2) deterioration of natural ecological environment and natural disasters; (3) severe pollution of environment and its difficulty in harnessing; (4) overuse and abuse of chemical fertilizer and its resulted water & soil pollution; (5) overuse and abuse of pesticide and its severe negative impacts on the quality of agricultural products and menacing to human health. A mathematic model for ecological security was also employed to qualify Hunan agricultural ecological security, using AHP (Analytic Hierarchy Process). In this quantitative evaluation, the basic unit was confined to administration region at county level. The evaluation index were composed of 3 classes, i.e., indexes reflecting pressure of agricultural resource, environment and ecology, indexes reflecting the quality of agricultural resource, environment and ecology, and indexes reflecting the reconstruction ability of agricultural resource, environment and ecology. Quantitative evaluation result...