农业生态系统结构的线性规划选优探讨

在崔营生产结构最优方案中,我们选择农业净产值最大为规划目标,同时设置了十七个决策变量和十九个约束方程.最优化方案指出,调整后农林牧结构由单一种植业为主变为农林牧工副各业相结合的林果业和畜牧业迅速发展的经济效益与生态效益相统一的新结构.

LINEAR PROGRAMMING OPTIMAL EXPLORATION IN THE STRUCTURE OF AGROECOSYSTEM

In order to gain experience, we have done linear programming in Cuiying place in Daxing county as a test in structure programming of agricultural ecosystem in Beijing-Tianjin region.In the optimum plan, we choose maximum net returns of agricultural production as an objective fouction, also set seventeen decision variables and determine nineteen constraint equations. The mathematical pattern can be written as follows. Maximize ConstraintThe optimum plan inbicates that a ratio of agriculture, forestry and animal husbandry will be relatively reasonable after it is fulfilled. It transforms the old structure of single crop plant production into a new structure of increasingly varied productions, helping each other forward in a common development.In the crop production, a net product value transformed from neg-tive into positive will increase ninety eight thousand dollar, 142 times and 33 times as much as before adjustmen of structure with separate forestry and animal husbandry.An analysis of ecological benifit suggests that a covering area of woods shall reach 31.6%, and shall increase one third in comparison with its profit in 1983, which may alter microclimate environment of the cultivated land, may improve the use of soil nutrient by crop plants and may increase transformable efficiency of the sun energy.A sensitivity analysis shows that chemical supply, balance between supply and demand for herbage, total seeded areas of crop plant production, the demandable amount of grains, peanut and vegetables are most sensitive constrained conditions effecting on an area of water melon.The test point of Cuiying shows that method of linear programming is feasible for optimization of agroecosystem structure. However, because of variable factors in agricultural ecosystem, therefore in order to make plan in keeping with the true world, it is necessary to take various parameters accurately, and data storehouse should be built.The linear programming of agroecosystem in Beijing-Tianjin region would be progressed in the way in which the whole region and each county carry out together. Viewing from the angle of the whole region, i.e. from top to below, first we should set about construction of data storehouse and determination of objective set, then according to various level of the regional agro-ecosystem, determine its plan of product structure. From below to top, it is that the scheme in some representative counties which are chosen from agricultural ecosystem with various natural-economic property worked out. Finally, according to objective set, overall plan is coordinated from an allround way.