三峡库区农林复合生态系统的效益评价

在对三峡库区农林复合生态系统大面积调查和定点测试的基础上，根据生态学原理和生态经济学原理，采用层次分析法（AH），根据对农林复合生态系统的生物量和生产力，物质流，能量流，价值流，土地利用等系统研究的结果，对三峡库区分布面积较大的4种农林复合生态系统从经济效益，生态效益，社会效益及综合效益方面进行了评价，并与农田生态系统进行了对比研究。这一研究结果将为科学合理地利用三峡库区土地资源，生物资源和气候资源提供重要的科学依据，为保护和改善三峡库区的生态环境，解决农村移民就地安置部分的生态问题及提高农村的经济发展水平提供理论基础。

Benefit Assessment of Agroforestry Ecosystems in the Three Gorges Reservoir Area

This paper is based on the adequate survey of agroforestry ecosystems in the Three Gorges Reservoir Area. Applying ecological principles and ecological economy principles, making use of AHP, and on the basis of the results of systematic researches on biomass and productivity, material cycle, energy flow, value flow and land use ratio of agroforestry ecosystems, this paper assesses the economic benefits, ecological benefits, social benefits and comprehensive benefits of the four types of agroforestry ecosystems with larger areas in the Three Gorges Reservoir Area. The agroforestry ecosystems are also compared with farmland ecosystems. The results showed that, the amount of storage, output and return of total N, P, K in the model of cypress forest-grassland-citrus forest-crops-vegetable (T-1), cypress forest-citrus forest-crops- vegetable (T-2), citrus forest-crops (T-3), cypress forest-crops (T-4) are respectively 3.96, 3.70, 3.19, 1.02 times; 1.85, 2.15, 1.99, 1.82 times; 2.56, 2.41, 2.66, 1.88 times of farmland ecosystem of wheat-peanut (T-5). The amount of storage, utilization, output and utilization ratio of sunlight energy of T 1, T 2, T 3 and T 4 are 3.56, 3.36, 3.19, 2.96 times; 2.84, 2.36, 2.32, 1.96 times; 3.09, 2.20, 2.61, 1.94 times and 5.68, 5.64, 6.32 and 4.86 times of T 5. The benefits cost rate (BCR) of four types of agroforestry ecosystems are 1.84, 1.97, 5.11 and 1.78 times of crop ecosystem of wheat-peanut, 1.11, 1.19, 3.08 and 1.08 times of wheat-vegetable (T-6). The order of BCR and net benefit of unit area among four agroforestry ecosystems and two farmland ecosystems is T 3>T 2>T 1>T 4> T 6>T 5. The efficiencies of land use of agroforestry ecosystems (T 1, T 2, T 3, T 4) compared with farmland ecosystem of wheat-peanut (assumed 1) are 1.88, 1.98, 4.85 and 1.69; with wheat-vegetable are 1.15, 1.21, 2.96 and 1.04. It means that the efficiency of land use is T 3>T 2>T 1>T 4>T 6>T 5. All of social benefit, economic benefit, ecological benefit and comprehensive benefit of agroforestry ecosystems are higher than farmland ecosystems. The order of social benefit is T 1>T 2>T 4> T 3>T 5 and T 6; the economic benefit is T 3>T 1>T 2>T 4>T 5 and T 6; the ecological benefit is T 1>T 3>T 2>T 4>T 5 and T 6; the comprehensive benefit is T 1>T 3>T 2>T 4>T 5 and T 6. The research results provide important scientific foundation to advisabely make use of land resources, biological resources and climate resources, and to protect and improve ecological environment in the Three Gorges Reservoir Area.