基于农业面源污染控制的三峡库区种植业结构优化

Planting structure optimization based on agricultural non-point source pollution control in Three Gorges Reservoir Region

基于农业经济效益最优和农业面源污染物减排的双重目标,运用线性规划模型,对三峡库区重庆段种植业结构和清洁农业生产进行了优化设计。通过对三峡库区重庆段种植业面源污染控制与种植业发展优化设计,得到三峡库区重庆段农作物净收益最大化的优化路径为:三峡库区重庆段粮食生产用地应保持约119.16×104 hm2,蔬菜用地保持约33.25×104 hm2,烟草、水果、茶用地应维持在17.05×104 hm2;在保证粮食生产稳定的前提下,应逐渐缩减玉米和大豆的种植面积,适当增加烟草、蔬菜、水果和茶的种植面积;在农作物生产过程中应大力推广清洁生产技术,扩大水稻、小麦、油料作物、玉米和大豆等种植的测土配方施肥面积,加强设施蔬菜生产基地建设,提倡蔬菜有机种植。通过这些措施,才能达到农业面源径流氮磷损失量减少30%的预期目标,才能实现农业面源污控制、农业经济转型和可持续发展。

Agricultural non-point source pollution has gradually become a major pollution source of lake eutrophication and deterioration of water quality in recent years. The Three Gorges Reservoir Region is both an important sensitive eco-economy area and a typical poverty-stricken mountain area. However, its unique geographical location, its irrational agricultural structure and its increasing serious agricultural non-point source pollution problems challenge the environment in this region. Hence, it is a necessity to take controlling agricultural non-point source pollution from the source as one of the most effective approaches. In current research, agricultural non-point source pollution control excessively depends on engineering and technology. Anyhow, the roles of agricultural planting structure adjustment and agricultural cleaner production which can reduce non-point source pollution should not be ignored. Promoting the adjustment of planting structure, reducing the use of chemical fertilizers and pesticides, and adopting agricultural cleaner production technologies not only help improve the land production capacity and agricultural products quality, but also effectively reduce the agricultural non-point source pollution. By these important measures for energy saving and emission reduction can be realized in Three Gorges Reservoir Region. Based on the dual goals of the optimal agricultural economic benefits and non-point source pollution emission reduction, the linear programming model was used to optimize the planting structure and clean agricultural production in the Three Gorges Reservoir Region. The optimization results showed that the optimal paths to maximize the crop net income were as follows： The land area for grain production should cover 119.16x10^4hm2but cleaner production area of rice-wheat, corn, soybean and tuber crops needs 31.91x10^4, 18.69x10^4, 6.79x10^4and 19.55x10^4 hm2; the land area for vegetables planting should be 33.25x10^4hm2 and its cleaner production area was 18.26x10^4 hm2; the total land area for tobacco, fruits and tea planting should be 17.05x10^4hm2 and the cleaner production area was 2.65x10^4, 10.28x10^4 and 0.95x10^4 hm2. In the premise of stable grain production, the conventionally grown grain, corn and soybean planting area can be gradually reduced. Otherwise, the planting areas of tobacco, vegetables, fruits and tea can be appropriately increased. In the process of crops production, according to the present ecological agriculture construction, the clean production can be vigorously promoted. The soil testing and formulated fertilization areas for food production in rice, wheat, oil crops, corn and soybean must be expanded. The organic vegetable planting can be increased positively. If the construction of the vegetable greenhouse is strengthened, the farmers’ household farming pattern will be affected, regulated, or transferred. Therefore, the losses of nitrogen and phosphorus in agricultural non-point source runoff can be decreased. The local government should encourage farmers to develop the sustainable agriculture and make them realize that if the agriculture nonpoint pollution can be mitigated, the greatest social welfare will be got in the Three Gorges Reservoir Region, which are the bilateral-won benefits. By this means, both the non-point source pollution can be controlled and the sustainable development of agricultural economy can be realized. Therefore, the optimization of various crops is important to control agricultural non-point source pollution. Space layout has played a decisive role in the process of the entire agricultural land system optimization. The economic and environmental comparative advantage of agricultural land can be achieved. The goal of total emission control of agricultural non-point can be achieved by reasonable structure adjustment and regional distribution of planting industry. Further research will be required to achieve the targets of controlling the total pollution emission.