Evaluation Of Farmland Productivity On Wuhu City Based On GIS

Farmland is the basis for agricultural production,but also indispensable resources for human survival and development,and food security related to the development of the whole society,farmland is fundamental to ensure food security.Currently,the County of Anhui Province has been fully completed fertility evaluation of arable land,but the municipal of fertility evaluation are exploring,make municipal farmland productivity evaluation not only able to grasp the spatial variability situation of soil nutrient,find out the productive potential,also has an important significance for the comparison of soil fertility in different counties,and the establishment of municipal soil testing database.In this study,take Wuhu City as an example,and supported by GIS,using the Delphi method selected 16 cultivated land fertility evaluation index,create AHP judgment matrix to calculate the weight of each evaluation index,based on fuzzy mathematical theory,to build membership functions,to determine the membership of each measure,and finally the use of the additive model to calculate the integrated fertility index,and according to a cumulative curve,divided farmland productivity levels.In the process of farmland productivity evaluation,make a research for the spatial variability of soil nutrients on Wuhu City.The results are as follows:(1)Spatial variability of soil nutrients.Make a research of spatial variability for soil organic matter,phosphorus and potassium,and using Kriging and GIS mapping technology to produce spatial variability of soil nutrients.The results showed that: organic matter,phosphorus and potassium in the coefficients of variation were 67.48%,50.49% and 26.36%,showed a moderate variation.Variation coefficients of P> K> OM.From the semi-variance analysis results,The ratios of nugget and sill [C0 /(C0 + C)] of organic matter,phosphorus and potassium were 51.10%,91.84% and 63.01%,in the regional context there is space relevance,in which the C0 /(C0 + C)values of organic matter and K ranged from 25% to 75%,with a moderate degree of spatial correlation by structural factors and random factors influence.The available phosphorus' s C0 /(C0 + C)is greater than 75%,its spatial correlation is very weak,mainly from random spatial variability factor.In addition,the space distribution of soil nutrients vary.Among them,the soil organic matter in Wuhu City,east of the highest content,followed by central and southwest,northeast and northwest with lower content;The regular of distribution of phosphorus is,east than the west,a strong heterogeneity,only a few western regional content is very low;potassium is manifested in the local area in north-central and east were relatively higher than those of local content in the southwestern and eastern regions.(2)Evaluation of soil nutrient status.Based on the patterns of spatial distribution of soil nutrients,according to the second national soil survey nutrient grading,soil organic matter,phosphorus and potassium were evaluated.The results showed that: soil organic matter content in general more moderate levels;soil phosphorus overall in the low level;and potassium content is generally at a low level.And with different cultivated land types,the status of soil nutrient is different.(3)Classification and evaluation of farmland productivity in Wuhu City.According to the relationship between the counts of evaluation units and farmland productivity index,farmland productivity will be divided into five levels,using of Arcgis9.3 draws maps of cultivated land fertility rating and statistics actual arable land of each class.the result is that,the first-class area is 39,553.83 hectares,accounting for 14.76 percent of the total cultivated area in Wuhu City;the second-class area is 74,942.83 hectares,accounting for 27.96%;the third-class area is 95,456.25 hectares,accounting for 35.62 percent;the fourth-class area is 37473.19 hectares,accounting for 13.98 percent;the fifth-class area is 20,594.94 hectares,accounting for 7.68%,the size of each cultivated land fertility level is third-class> second-class> First place> Four other places> five other places.According to the situation of the levers of farmland Productivity,analyzes the reasons of difference and the change regulation on terrain,soil types and parent materials etc.of cultivated land fertility,and gives the corresponding countermeasures.On the whole,with the change of terrain in the direction of plain polder area-depression-mountains and hills,and soil parent material changes by river alluvium-the Yangtze river alluvium-under loess-Alluvial material-argillaceous rocks eluvial material,and the type of soil along the paddy soil-red soil-yellow brown soil transition,the cultivated land fertility continues to weaken in Wuhu City.