The Study On Object Selection Of Cultivated Land Protection In Land Use Planning Of China

China's land resources are extremely scarce in comparison to the world average with more than 21 percent of the world's population living on cultivated land which is less than 10 percent of the total area available on earth. Cultivated land protection is one of the most important aspects in land administration. The object of cultivated land protection is a set of aim, demands and executive consequences of land protection policy. The characteristics include diversity, hierarchy, stage and rationality. Cultivated land plays different roles in satisfying requirement of social and economic development. Based on these understandings, there are discrepant objects between country and province. The rational object of cultivated land protection can ensure effective implementation of land use planning, and balance interests of regional land use.This paper construct the object selection system of cultivated land protection of land use planning. Methods of multi-objective linear programming, genetic algorithm, factor analysis and grey correlation degree are employed. The paper focuses on how to get the rational object of cultivated land protection in the level of national and provincial land use planning, and researches how to assign task of cultivated land protection for provinces and counties of typical province. The following conclusions are drawn through the study:(1)As China is the most populous county in the world, the food security has been a primary concern of researchers and politicians for decades. It is hard to satisfy China's consumption needs of food from international market. The food security should depend on national grain production.(2)Cultivated land is a subsystem of the land use system. The object selection of cultivated land protection belongs to the multi-objective optimization. The Pareto solution sets of total area of cultivated land are obtained by Multi Objective Genetic Algorithm method. The optimal solution of cultivated land protection is determined by OWA and CWAA in different objective preference. Based on the results and national social and economic development goals, the object of cultivated land protection is set up The qualitative object are drawn as followed:the food security is core goal; the food needs should be satisfied by these ways which are steadily improving quality of cultivated land and maintained a certain amount of arable land; reserved cultivated land should be properly developed for scares water resource and soil erosion; the sustainable use of cultivated land is ultimate goal. The quantitative object is described as followed:by 2020 in China:The yield per unit area of grain is 5250 kg/hm2, the total area is 11948×104 hm2, the food production capacity more than 63831.39×104 tons; the increased area of cultivated land should be less than 40% of total increased area (367×104 hm2) by the way of land consolidation.(3)The land administration has a spatial difference in China. The regional resource-niche of cultivated land is determined by resources endowment, social and economic environment, agricultural technical condition and regional economic position of cultivated land. Based on the resource-niches, protective amount and cultivated land requisition-compensation balance index of the provinces are calculated. The provinces with higher niche will be assigned more protective index. According to balance index, the provinces can be distinguished four types. The first type is the provinces which have great compensation capability of cultivated land and the balance index above 1; the second is the provinces which have great compensation capability of cultivated land but the balance index blow 1; the third is the provinces which have weak compensation capability of cultivated land but the balance index above 1; the last one is the provinces which have weak compensation capability of cultivated land and the balance index blow 1. We can get such conclusions:The provinces which have developed economic but resources shortage are still in important position in cultivated land protection due to superior agricultural production condition. The balance index will be changed with labor, agricultural production conditions and land conversion's changes.(4)The main task of cultivated land protection is finishing the object of China to province government. Meanwhile they take the press of economic and social development. Xinjiang have the most abundant reserve land resources and poorest water resource in comparison than other provinces. Although photosynthesis-temperature resources are favorable for crop growth, but ecological environment is very fragile. The key to the sustainable use of cultivated land is coordinated confliction between agricultural irrigation water and ecological water demand in Xinjiang. Based on analysis available water resources of cultivated land of Xinjiang and predicting the water-saving irrigation technique level, the control area of cultivated land of Xinjiang was determined. The qualitative objects are drawn as followed:ecological security is core in Xinjiang. The main task is to coordinate the conflict between cultivated land and ecological land. The reserve land wouldn't be explored until ecological and other water demand is satisfied, and the area of cultivated land should be steadily increasing by developing water-saving irrigation. It is the quantitative object which range of cultivated land area between 411.4×104 and 474.3×104hm2 in Xinjiang by 2020.(5) The model of dominance degree of cultivated land protection was constructed which is a basis to allocation of cultivated land protection indices in county scale. The first and second of dominance degree counties are Sanga and Qapqal. The county with lowest difference is Wuqia. The results indicate that the counties with greater dominance degree have more flexible implementation in cultivated land protection policies.