Evaluation Methods and Its Application on Potentials of Land Resources based on GIS Technology and Theories of Landscape Ecology

The center of new rural construction of China is to build a modern agricultural system,and the mark of modern agriculture includes industrialization and specialized farming.Agricultural modernization depends on the potentials of land resources.Landscape pattern of land resources has a strong impact on potential of land resources(SPLR).This paper focuses on discussing how to set up a indicator system including patch area,richness index,patch square index,concentration index and farming radius for evaluating SPLR.Taking the arable land resources evaluation in a Karst mountain area as an example,the authors use the landscape pattern indices and terrain indices combined with DTM data GIS technology to evaluate the SPLR of the Karst mountains areas.Because terrain gradient is also a key factor to SPLR,the paper classifies the gradient into three grade: P≤5°,5°P≤15°,P15°("P" means gradient),two regions of the Karst terrain: river valley(called "region No.Ⅰ"),Karst peak cluster-depressions and Karst peak forest-valley(called "region No.Ⅱ") according to the terrain gradient for evaluating and comparing different potential of land resources in different terrain regions.The study result shows:1) The richness index,patch square index and concentration index of land resources varies with terrain gradient.The proportion of gradient areas in region No.Ⅰ(P15°) is 0.6%,and the richness index,patch square index and concentration index of arable land resources in the region is 67.1,1.48,29.7 respectively.The proportion of gradient areas in region No.Ⅱ(P15°) is 89.5%,and the richness index,patch square index and concentration index of arable land resources in the region is 11.8,1.63, 11.2 respectively;2)The effective factors of the comprehensive SPLR include proportion of flat area(S1,P≤5°),proportion of light slope terrain area(S2,5°P≤15°),richness index,patch square index and concentration index,the most important factor to the comprehensive SPLR is the proportion of flat area(S1),which is weighted as 0.33;3) The comprehensive SPLR of region No.Ⅰ is 0.91,more than three times of that in region No.Ⅱ;4) The farming cost in region No.Ⅱ is nearly more than nine times of that in region No.Ⅰ.In summary,the SPLR is strongly restricted by the combination of spatial landscape of land resources and terrain conditions.