南方丘陵区农业生态系统适应能力及其驱动因子——以衡阳盆地为例

全球变化背景下的适应性研究引起了广泛关注。南方丘陵区是典型的水稻农业区,研究其农业生态系统适应性尤为重要。采用主成分分析法对衡阳盆地农业生态系统适应能力进行了定量研究,分析不同适应能力区的适应性主要驱动因子。结果表明:适应能力的分布规律为衡阳市区最高,各县域适应能力呈现出盆地中部低、四周高的分布规律。不同适应能力区适应性驱动因子各异,高适应能力区主要驱动因子是经济条件,水热配合条件和灌溉设施是较高适应能力区的主要驱动因子,低适应能力区的主要驱动因子是人口规模和水土保持,热量和地形条件是极低适应能力区的主要驱动因子。高适应能力区因以农药和化肥的施用量为主要驱动因子具有短暂性,较高适应能力区以良好的水热配合条件和灌溉设施作为驱动因子具有可持续性,因而较高适应能力区的发展潜力超过高适应能力区。

Adaptability of agricultural ecosystems in the hilly areas in Southern China: a case study in Hengyang Basin

Adaptability is the response to external pressures or actions that people make efforts to reduce the adverse effects caused by global change with the aim of harmoniously inhabiting the environment. In studies focused on global change, adaptability has attracted great attention. There have been many studies on the ecological adaptability of plants under global change. The model of water ecological adaptability of upland crops has been discussed, and the eco-environment adaptability under changing climates in the past decade has been investigated. However, little research has been conducted on agricultural ecosystem adaptability (AEA). Agricultural ecosystem adaptability is affected by the natural environment, as well as by social and economic factors. Different factors have different driving or restraining effects on AEA values. The rice farming regions of the hilly area in the Hengyang basin in southern China is the basis for our AEA study. Our study on AEA values is quantitative and applies principal component analysis to analyze the main driving factors affecting adaptability in the different regions of our study area. Based on the calculation of the size of the driving force and AEA values, we analyzed the adaptability of the different regions. The AEA concept helps maintain sustainable agricultural development. Sustainable agricultural development is more likely to recover quickly from environmental disasters (such as floods or droughts) or economic (i.e. poor, lack of food, fluctuations in commodity prices) crises. Based on natural, social and economic factors, we establish the AEA indexes for different regions in the Hengyang Basin. Our findings show that AEA is highest in Hengyang. In the other regions, the central parts of the basin have low adaptability and the surrounding regions have high adaptability. Good economic conditions are the main driving factors of a high AEA, and good hydrothermal and irrigation systems induce high adaptability. Hengyang is the economic, political and cultural center of the Hengyang Basin. The per-capita net income of farmers in Hengyang is the highest in region, and the farmers'' Engel coefficient is the lowest. Nevertheless, the use of pesticides and chemical fertilizers are still prevalent in Hengyang. Changning and Leiyang have good hydrothermal and irrigation systems. Flood and drought disasters seldom occur in these cities and this contributes to a high adaptability. Population size and the conservation of soil and water are the primary driving factors in low adaptability areas. Extreme heat and harsh terrain conditions lead to the lowest agricultural ecosystem adaptability. The application of pesticides and chemical fertilizers result in a temporary high AEA, which cannot be sustained. High AEAs resulting from good hydrothermal and irrigation systems are sustainable. The development potential of a region with high AEAs is greater than that of regions with low AEAs. The low adaptability areas can improve their AEA ratings by not only using the natural environment in a sustainable way, but also improving social and economic factors. Increasing the production of good crop strains, improving irrigation and drainage conditions and developing advantageous agricultural policies are very effective ways of enhancing adaptability.