Study On Agricultural Land Suitability Evaluation In Karst Area Support With RS And GIS

The suitability evaluation for Agricultural land is one of the most major contents of land resource research in last decades,which divides suitable graduation of Agricultural land,and then,according to the type and intensity of the restricted factor of each land unit,makes rebuild measures in line with the local conditions,and offer service for scientific management,rational utilization and planning land.Concepts and principles of land suitability evaluation are detailed introductive in this article which makes simple introduction on content system and method of《A framework for land evaluation》(FAO).In this Paper,Zhenning Buyi nationality & Miao nationality autonomous county(short for Zhenning county) borough as the study area,which is part of GuiZhou Province's Anshun City,belongs to the representative karst area.As for different land utilization type,the natural and socioeconomic condition should be analyzed to determine the sort system and build the indices system under the direction of the basic theories.The rocky desertification grade is considered as a index in this especial area.And the weight of eaeh factor is calculated by the measure of Analytic Hierarchy Process.Specifically,the article utilizes the remote sensing images as information sources to process and capture the land information. The results are as following:1.There is high suitable farmland by 35,143.78hm~2 of Zhenning County that account for 24%of the present agricultural land area.It mainly distributed in north and mid-north of Zhenning County,which equates present farmland distributing;There is moderate suitable farmland by 50,656.54hm~2 that account for 34.59%of the present agricultural land area.It mainly distributed in mid-north and mid-south; There is morginal suitable farmland and unsuitable farmland by 60,633.58hm~2 that account for 41.41%of the present agricultural land area.2.There is high suitable forestland by 37,036.40hm~2 of Zhenning County that account for 25.29%of the present agricultural land area.It mainly distributed in north,south and mid-east;The moderate suitable forestland mainly distributed in north and south of Zhenning County,which by 60,855.25hm~2 that account for 41.56%of the present forestland area,the present using types is Shrub Land and short of forest land;There is morginal suitable forestland and unsuitable forestland by 37,036.40hm~2 of Zhenning County that account for 25.29%of the present agricultural land area,it mainly distributed in high rocky desertification degree area.3.The grassland play a great effection on preventing rocky desertification get higher,we suggest planting grass to improve ecological environment.4.There is 74,505.21hm~2 land which is suitable for farmland, 56,269.81hm~2 land which is suitable for forestland and 12,757.33hm~2 land which is suitable for grass land,the result is equates present agricultural land distributing.The present area of farmland is 57,127.59hm~2,18,573.37hm~2 in it is high suitable for farming,which account for 33.46%of the present agricultural land area;The present area of forestland is 60,342.38hm~2,22,994.8hm~2 in it is high suitable for forestland,which account for 38.11%of the present agricultural land area; The present area of grassland is 28,770.17hm~2,2,598.38hm~2 in it is high suitable for grassland,which account for 9.03%of the present agricultural land area.