Evaluation Of Potential Land Productivity On Ecotone Between Farming And Animal Husbandry

How to evaluate the potential land productivity in the region with diversified physiognomy types,to generate gridded datasets,and to establish a reasonable evaluation model are important and fundamental work for studying agriculture production,environment protection and sustainable use of water and soil resource at regional scale.There is typical loess ravine terrain,more than ten large areas of the plateau, and is mixed plateau,ravines,girder,valley,flat plain,chain of mountains,slope in Qingyang research region.Qingyang lie deeply in China's interior,the complex terrain conditions characterized by mountainous regions induced complex spatio-temporal variations on such eco-environmental variables as temperature and precipitation.The variations of these variables result in highly differed conditions in heat and water,which will directly determine the potential land productivity in Qingyang.These eco-environment variables were quantified in space and time domains,and griddized datasets were generated,evaluating potential land productivity based on these conditions is the main research question need to solve in this thesis.Based on the complex topography and the characteristics of the Loess Plateau,refer to previous research results,and on the basis of objective analysis evaluation of the regional natural and socio-economic resource,this research took Qingyang in Gansu province as research region,selected ten affected factors from three aspacts as terrain physiognomy,climate condition,soil physico-chemistry condition,based on the ARC GIS 9.0 Geographic Information System software, adopted the scores which are made by experts and the Tell Fay method to identify the subjection function of several affected factors and introduced Analytical Hierarch Program(AHP)and Fuzzy Mathernatics Theory(FMT)to identify the weight of ecological index factors.Meanwhile,the spatial databases of correlative ecological index factors have been established according to the GIS spatial interpolation module,and then according to the spatial overlay analysis of the ecological index factors,the potential land productivity grade distribution of Qingyang region was simulated using the spatial computation of the evaluating models which are established by the ecological index factors.Ultimately the geographic distribution map about the potential land productivity grade distribution of Qingyang region is formed,and agricultural sustainable development counterplan was supplied in order to provide theoretical basis for development of agricultural resources of Qingyang and the development of the Northwest,and to supply reference for the development of regional agriculture policy-makers and managers.Its main conclusions as follows:1.Potential land productivity effective coefficient in Qingyang research region changed from 0.257 to 0.916,average is 0.587,the natural productivity level of entire Qingyang region is medium-up.2.According indicators factor on potential land productivity and contribution for land productivity as well as the especial topography of Qingyang region,indicators of potential land productivity were identified as follow:Slope(S),aspect(A),annual accumulate temperature(T),annual average precipitation(Aap),frost-free period(F), relative humidity(H),total nitrogen(N),total phosphorus(P),total potassium(K), organic matter(O)and so on.For Qingyang research region,the main influencing factors are precipitation and slope,generally,the less precipitation,the smaller the slope,the worse the quality of the soil,and the lower of the soil natural productive potential.3.Potential land productivity integrated index model of Qingyang region was obtained:PLPⅡ=Aap×0.2761+S×0.2080+A×0.1041+T×0.0395+F×0.1183+ H×0.1578+N×0.0307+P×0.0078+K×0.0181+O×0.03924.Spatial database of ten ecological indicators factor in Qingyang were established,levels distribution map of Qingyang region was simulated,with the character of potential land productivity gradually increasing from southeast to northwest.5.This study adopt GIS technology firstly to calculate and simulate potential land productivity for complex topography region as Qingyang in Gansu Province,and the evaluation result is in line with the local situation of the region.This result not only contribute a beneficial exploration for carrying out studies about the evaluation of the potential land productivity of Longdong ravine region,but also supply credible information and decision-making basis for government departments such as agriculture,land,forestry etc.so as to carry on agricultural structure adjustment,land planning and renovation,ecological environment construction.