Evolution Of Arable Land And Optimization Of Spatial Distribution Of Basic Farmland In Yinchuan

Arable land is the essence of land resources, which is a basic condition for human access to agricultural products. With the condition of our country is fewer land resource and more people, the situation of urban expansion occupied the arable land is serious; it determines the importance of arable land protection. This paper selected Yinchuan Plain as a typical representative study area, which combines of remote sensing and geographic information system to analyze the characteristics of the arable land to be set in the context of rapid urbanization. To identify the key driving factors of the arable land’s change, and predict the trend. Finally to propose indicators and methods of basic farmland layout optimization, provide the theoretical basis and scientific support for the arable land protection and regional sustainable development. The main conclusions of this paper are as follows:(1) In the context of rapid urbanization, by analyzing the quantity, the space and quality variation of the arable land which show:From1989to2009, the total amount of arable land shows the characteristic of sustained and rapid increase. Before1999, increase in arable land mainly located in the new city (Xixia District); after1999, which is mainly located in eastern old town (Xingxing District) and the northern suburban county (Helan County). As the characteristic of spatial and structural change, before1999, the conversion of arable land focus on the unused land in west city; After1999, which are focus on the rapid expansion of the central city occupied arable land, the development of the periphery of the agricultural production circle, the land remediation of the entire region. The gravity of city’s arable land moves to the northwest, agricultural production has formatted local stability region, the proportion of "welt construction" occupied arable land is large, and the phenomenon is more significant after1999. The average natural quality of Yinchuan’s arable land is sustained decrease, and the phenomenon is more meaningful before1999. And through the arable land landscape index shows arable land fragmentation experienced the process of first up and then down, and the intensive use of arable land continued to increase.(2) Combine the statistics township panel and classification of remote sensing data, to explore the driving forces of Yinchuan’s arable land from1999to2009, which shows:Natural quality of arable land and raw distance are the important driving factor of the reduction of arable land, and it proved the reduction of arable land has a certain preference on natural conditions and geographic conditions, the immigration development is the main driving force to increase the number of arable land, and it is also proves the increase the total population and rapid urbanization are the main reasons for the arable land increase; Economic conditions have two driving action on the quantity change of arable land, and make use of economic measures to control the number of arable land, from a macro point of view, which need to adjust the industrial structure, it is means to reduce the production value of the secondary industry gradually. From the microscopic point of view, which need to protect the farmers’income level.Planning crops have a remarkable biphasic effect on the promotion of arable land increased and decrease of arable land reduce, Yinchuan as an important commodity grain base in irrigated areas of the strategic positioning which for the protection of arable land had a positive impact.(3) Under the constraints of land use planning, this paper predicted spatial distribution of the arable and in2020. Using remote sensing images of1999and2009combined the limit of Yinchuan municipal land use planning space layout and indicators, by CA-Markov model to predict the spatial distribution of land use in2020. The prediction result shows in the upcoming planning period arable land is still the core class of land use structure; the number of arable land will still increase. The reserve resources for the development of arable land has been nearly depleted, the quality of arable land will stable and slightly improved, and over-exploitation of arable land will bring the degradation seriously, so it is focus on protecting the environment and coordinated water supply balance, the key to achieve the arable land protection sustainable development is the implementation of high-quality arable land protection policy.(4) Based on the Yinchuan’s land use change, for the characteristics of Yinchuan, the paper build an integrated system of quality evaluation of arable land which based on natural quality of arable land, economic drivers, planning forecast and ecological risk assessment, and at the same time set three kinds of scenarios of the best quality, the best economic and the best ecological. By selecting polygons as the evaluation unit, combining quality arable land location, polygons attribute and use types, and which propose comprehensive ranking model based on polygons innovatively, to achieve a high-quality arable land protection centrally, through the model we proposed the method of delimit the scope of basic farmland protection, and delimit the scope. The comparative analysis shows Yinchuan’s current delineation of basic farmland protection areas consider three aspects of the natural quality, the economic driver and the ecological risk, the overall layout is reasonable.