County Land Productivity Evaluation Method And Its Application

This paper,selecting Xundian county of Yunnan province as a case study,aims at proposing a evaluation method for the county arable productivity based on the Fuzzy Mathematics Model, with using the technologies of Geographic Information System(GIS),Remote Sensing(RS)and Global Positioning System(GPS)and combining with the Analytical Hierarchy Progress(AHP) and Delphi Principle.This paper,in allusion to the actuality of the arable land resources in Xundian county, establishes the arable land resources database based on the technology of 3S,by collecting and standardizing relative information of maps,datum,sampling and testing date;the assessment unit creates a superposition graph of land use actuality map,land type map and agrotype map,17 essential evaluation factors are decided from the aspects of the condition of nutrient,soil physic-chemistry character,parent material,irrigation condition,land management etc,and the weight of indicators has been calculated by using Delphi principle;the evaluation model of Fuzzy Mathematics are to be applied,linking with the Analytical Hierarchy Progress,to calculate the integrative index of Xundian county's farmland fertility;finally the evaluation results are obtained by counting and analyzing the assessment outcomes:The total area of the Xundian county is 359800 hm~2,in which the arable land area is 73921.07 hm~2,taking up 20.5%of the total area.It gives priority to the arable land grades of three to five,the two grade and six grade is comparatively not enough and the grade one is much less in which grade one 164.02 hm~2,grade two 5096.02 hm~2,grade three 26881.19 hm~2,grade four 18617.28 hm~2,grade five 18802.38 hm~2,grade six 4360.17 hm~2,sharing each percentage as 0.22%,6.89%,36.36%,25.19%,25.44%,5.90%respectively.The local features of the arable land productivity grade distribution ara relatively clear,the grade level is closely associates with type of topography,soil type and altitude,Showing a clear geographical distribution,with the arable land grade that is elevating,landforms along the direction of ease slope-Piedmont tilt the ground-gentle Kong-valley terrace-near mountain terrace changes;at the same time,as the altitude gradually increases,presenting sloping land,the agrotype transformes from Cinnamon-alluvial,Cinnamon leaching and Chao Cinnamon to Kuroshio soil,Cinnamon influx of soil,Cinnamon Shajiang black soil and then to Cinnamon soil,brown soil,Stone Zhatu and gravelly soil.This paper Integrates the technology of 3S with traditional evaluation methods of the arable land fertility,analyses the variation features of farmland fertility and soil fertility factors in the temporal and spatial,makes the best grasp of arable land resources of quantity,quality and distribution,which is of great practical significance to rational use of arable land,effective protection and improvement arable land fertility,agricultural planning and the development of modern agricultural science and technology in xundian county.