GIS-based Study On Location Selection And Designation Of High Standard Basic Farmland In Hilly And Mountainous Area

Almost half of the land area in our country are hilly and mountainous, the farmland quality of these area is generally not good as it is restricted by the topographic condition. In addition, the construction land has eroded the high quality farmland nearby the cities and towns in recent years, so the food problem is more and more obvious. The construction of high standard basic farmland is benefit for the improvement of quality of farmland, the assurance of food safety, the stability and persistence of the economy and environment of the country. It is an important chain in constructing high standard basic farmland and main task in land reclamation and reallocation to configure and design the high standard basic farmland scientifically and reasonably. It has become an important method to solve the food problem in our country. As a result, the research focusing on the spatio-temporal distribution and designation of high standard basic farmland is of high practical applicability. Meanwhile the research results provide reference and decision support for the construction of high standard basic farmland of the hilly and mountainous area, which is of practical significance.Nanchuan is located at the edge of Sichuan Basin, which is typical hilly and mountainous area. This paper took Nanchuan in Chongqing as example, the high standard basic farmland in researched area was designated and planned based on the method and technology of GIS and focused on the farmland in second land survey data. The research include the following parts:(1) According to the special topography of hilly and mountainous area, explore the meaning of the construction of high standard basic farmland. Then analysis the condition of basic farmland in researched area from four aspects including quantity, quality, distribution and existing problems. Compare it with the basic farmland in flat area and investigate the evaluation indexes that affect the site selection of high standard basic farmland, lay a foundation to distribute the high standard basic farmland scientifically.(2) Obtain the evaluation indexes based on GIS technology and standardize the indexes. Acquire the comprehensive weight of each evaluation index by analytic hierarchy process and entropy Coefficient Method. Structure the evaluation system of high standard basic farmland. Based on above results, normalized decision matrix is structured. Sort all the farmland by approximation method. Accumulate the farmland quantity to high standard basic farmland index that Chongqing assigned to Nanchuan. At last output the comprehensive evaluation result map of selecting farmland into high standard basic farmland.(3) Determine the distribution of high standard basic farmland in Nanchuan in2012-2015according to the site selection evaluation result of high standard basic farmland, which is conducted by two aspects including towns and land-using comprehensive partition. Meanwhile, based on different requirement of the construction of high standard basic farmland and combined the significance, demonstrative, fund of project area, confirm the sequence of construction of high standard basic farmland. The research is divided in two aspects of construction date and construction mode.(4) After the determination of the site of high standard basic farmland, this paper use GIS technology and take the case of Nongjia in Tieshu town to study the designation of high standard basic farmland. In the aspect of land leveling project, analysis the raster data and calculate the excavation and filling earth volume in land leveling with the aid of DEM; In the aspect of the design of drainage project, analysis the hydrology of land surface based on DEM, extract the flow orientation, confluence cumulant and river network of surface water. Based on above and decide the size and length of the irrigation canals and ditches; In the aspect of field road design, calculate the raster data of road cost and weigh the cost and distance, at last obtain the optimum road network in project area by shortest path analysis.The research results indicates that GIS technology is of highly practical value in spatio-temporal distribution and designation of high standard basic farmland, which also greatly improves the calculation efficiency and accuracy.