A Study On Potential Evaluation Of Farmland Consolidation In Renhuai Based On GIS

Being under the extremely intense contradiction between human and land triggered by its weak environment, Karst region shoulders the pressure not only of meeting the needs of construction land that is essential in development of society and economy, but also of seriously protecting cultivated land. Renhuai, as a typical representative of Karst region, has the problem mentioned above. Being the important part in the work of farmland consolidation, the potential evaluation of farmland consolidation contributes to scientifically analyzing consolidating potential and spatial distribution characteristics. It has the great significance of rationally making land consolidation programs, easing regional human-land contradiction, and relieving the pressure of requisition-compensation balance of cultivated land.After the comprehensive analysis of relevant references abroad and at home, selecting Renhuai in Guizhou province as a case and putting administrative villages as evaluative units, this thesis constructs the indicator system of potential evaluation of farmland consolidation by combining the actual condition in Renhuai. The index weight is synthetically confirmed by Analytic Hierarchy Process(AHP) and BP Artificial Neural Network(ANN). And finally the weighted comprehensive index model is established so that the comprehensive potential indexes of corresponding farmland consolidations of the evaluative units in Renhuai are figured out.Utilizing the Descriptive Statistical Analysis, Correlation Analysis, Geostatistical Analysis and so on, this thesis does the spatial variation analysis on evaluative results of consolidation potential of farmland in Renhuai, and then probes into the reasons and mechanisms resulted from the difference of consolidating potential of farmland. In the end, some conclusions are drawn as follows.(1) The largest limiting factor influencing the level of farmland consolidation potential in Renhuai is intensity of stony desertification. In the regions of stony desertification with different levels, the potential values of farmland consolidation are ranked in this way: Non-Karst region﹥Sub-Karst region﹥Typical Karst region.(2) There is obvious spatial heterogeneity in distribution of farmland consolidation potential in Renhuai. It is shown in spatial framework analysis that Global Moran’s I= 0.2800, which indicates that the potential distribution of farmland consolidation in Renuai has not only obvious spatial autocorrelation but also partial agglomeration effect. According to the partial spatial autocorrelation analysis, high potential values form “High-High” aggregation respectively in the southern and northern part of Renhuai. In the north, the aggregation stripes from north to south are formed along Sanhe County, Daba County and Erhe County, and in the south the aggregation core from northwest to southeast is formed in Maoba County. The low potential values respectively forms “Low-Low” aggregation in administrative border of Renhuai.(3) From the perspectives of spatial form and direction, the farmland consolidation potential in Renhuai is of variability controlled by constitutive factors, such as microscopic landform, etc. Kriging Spatial Interpolation shows that the farmland consolidation potential has variant spatial forms. Regarding the high-value aggregation as the core, potential successively diffuses to the periphery in decreasing order and presents the typical “Core-Border” construction. Besides, the potential variability is featured by directionality. In the horizontal direction, potential values are respectively in “High-Low-High” distribution pattern from south to north, and in “Low-High-Low” distribution situation from east to west. In the vertical direction, potential values are decreasing with the increment of altitude. It is also shown in geostastical analysis that the spatial structure rate in the semivariable function model parameter of farmland consolidation potential is C0/(C0+C)= 0.20337<0.25, which belongs to intense spatial autocorrelation indicating that constitutive factors cause variation. And there exists obvious negative correlation between potential evaluative results and macroscopic landform factors.Finally, on the basis of comprehensively analyzing spatial difference of farmland consolidation potential in Renhuai, the thesis divides evaluative results into various levels and areas:(1) The potential evaluative results are divided into five levels. The comprehensive potential indexes decrease from I to V. On the level of V, the dispersion degree of interior comprehensive potential index is highest, the involved agricultural acreage is smallest. On the level of II, the dispersion degree of interior comprehensive potential index is lowest, the involved agricultural acreage is largest.(2) The farmland in Renhuai is divided into five consolidation areas and corresponding consolidating orientations are preliminarily proposed afterwards.