| In order to carry out the strategy of the sustainable development of the Communist party of China , arable land must be protected. It may build up rivalrousness in market. It is very important that how to make use of and protect it effectively to our country ,which has many people and little crop land. Vegetable land that is an embranchment of arable land has its basic identity. We must wake up to importance of fertility and environment in order to increase stably in agriculture and produce non-environmental vegetable .Processing estimate about its quality is a premise to utilize with reason. The assessment result will serve for reasonable print of land use and uniform non-pollution vegetable land. We will adjust crop species gradually according to soil fertility and environment quality.Geographic Information System (GIS) is a wholly new advanced spatial technique, which took its place in 1960s and has been developing swiftly and violently with the development of computer technology .So far, it has been applied in almost all areas dialing with geographical or spatial information. That GIS in used in estimate of vegetable land has significance and value . because of the function which connects spatial data with attribute data.This research was conducted at Zhouxiang town in Cixi county of zhejiang province. With the support of Arc/info8.2, MapinfoS.O, Arcview3.2 software, basic data in the study area has been established, which including indoor analysis , extraventricular research , land use map .material of society and economy. And based on the database, vegetable land quality evaluation has been attained as follows: Survey in the fieldWe gathered 10 samples of Vegetable Land in Cixi in Oct.2001and 26 samples in72Zhouxiang in July.2003. And each sample was serted to by GPS.Analysis in the doorThese items included particle composition, bulk density, organic matter, pH, available N,Olsen-P,available K, total salt concentrations and fractions of four heavy metals (Cd> Cr, Pb> Hg) and residua of DDT & BHC pesticide. The principal component analysis was employed for relations among the heavy metal.Basic database establishmentThe design of database include objectives, principle, demand, analysis, conception and logical structure designs and data classification. Mapping data is mainly managed and edited with the aid of MAPINFO,ARC/INFO. The latter is the tool for editing, establishing of topology for point, line and polygon features. The spatial database for mapping of landform, soil nutrient land use, planning ,and attribute database have been established ,while the statistical database have been founded in EXCEL software.Through the common item, spatial database can be joined with statistical database.Vegetable land quality evaluationAccording to standard of soil environment quality, standard of class of vegetable land, land in the county, contamination, the class was decided. The research endowed evaluation index with marking for quantity expression of result of estimate.The objective weight was obtained by Method of Analytical Hierarchy Process after calculation and verification If consistency. The cell of 20 X 20 meter was conducted in this research, very vector map has been resampled to the same standard grid map. This research adopt the layer analysis method to decide the impact of item in order to decide the class of vegetable land.According to standard of safety qualification for agricultural product invironmental requirements for origin of non-environmental pollution vegetable, heavy metals (Cd> Cr> Pb> Hg) and residual of DDT & BHC pesticide are under standard of soil environment quality, so vegetable land in Zhouxiang may be used non-environmental pollution vegetable land.According to standard of agriculture -the class of vegetable land , particlecomposition and pH are moderate,but organic matter, available N and available K are under.Cd and Cr are very under ,but Hg is in some sort high.By evaluation, 11 samples belong to the third class and 15 samples...
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