Evaluation Of City Cultivated Land Fertility Based On GIS

National evaluation of farmland work were taken by ministry of Agriculture in2005as farmland productivity determines the sustainability of agricultural production and even threatens the food security of the country, County-level of this work has been nearing completion, however, it cannot meet the municipal or provincial demand for its limitations. So it is imminent to find out municipal or provincial evaluation of farmland process. This article takes Fuyang City, Anhui Province for example. In this study, a workflow has been explored initially which can be applied to municipal Evaluation of Farmland, meanwhile, a detailed analysis and research about entire Fuyang of fertility distribution has been taken. The results are as follows:1. Under the support of GIS and combined with the Fuyang counties, regions and municipalities’ land resources management database, soil maps, land use maps and administrative maps are eventually overlay which formed16,175evaluation units, meanwhile, land resources management information database of Fuyang are constructed. Cultivated land fertility evaluation index system of Fuyang are established by using the Delphi method, AHP method, and then explored a set of technical process of Fuyang municipal Evaluation of Farmland.2. Farmland of Fuyang are divided into five levels combined with farmland evaluation index system of Fuyang. IFI>0.7485are classified as first-class area of82,985.32hectares, accounting for14.42%of the total cultivated area in Fuyang. IFI between0.7320and0.7485are classified as second-class area of153320.32hectares, accounting for26.63%of the total cultivated area in Fuyang. IFI between0.6900and0.7320are classified as third-class area of220312.68hectares, accounting for38.27%of the total cultivated area in Fuyang. IFI between0.6550and0.6900are classified as fourth-class area of73702.24hectares, accounting for12.80%of the total cultivated area in Fuyang. IFI<0.6550are classified as fifth-class area of45346.00hectares, accounting for7.88%of the total cultivated area in Fuyang. First-class focus on Shajiang black soil and sand loess ginger, which account for5.37%and5.69%respectively of the total arable land,49.47%and39.22%of each soil type, however this class soil don’t include mud bone black soil, mud bone soil, linen sand, sand and mud slope loess, silt slope loess. Second-class focus on the plainer soil, lime concretion black soil fields, sand and mud slope loess, which account for8.45%,11.24%and3.46%respectively of the total arable land,74.92%、49.01%and44.32% of each soil type, however, this class soil don’t include sand, silt black soil, silt slope loess and silt soil. Third-class include all types of soil and mainly focus on the black silt、sand loess ginger and shajiang black soil, which account for12.08%、7.11%and4.81%respectively of the total arable land,74.92%、49.01%、44.32%of each soil type. Fourth-class focus on black silt, mud bone soil, the soil of the two together and white loess, which account for2.11%、1.04%、1.61%and1.23%of the total arable land. Fifth-class have little area and focus on combined soil silt soil and sand, which account for1.60%、1.13%and1.28%of the total arable land. Distribution of first-class is more fragmented which are mainly concentrated in the north-central region and the second class is more concentrated, mainly in the western region. The third class is distributed more widely and evenly in every region. Fourth class and fifth class are mainly focus along the central and southern areas.3. Through analysis of soil nutrient data in Fuyang, the average value of soil organic matter and total nitrogen are15.3g/kg and0.97g/kg at shortage level. The average of available P and K are19.2g/kg and142mg/kg at middle level. The average of available Zn and water soluble boron are1.14mg/kg and0.62mg/kg at lower-middle-level. The average of available Fe and Mn are40.37mg/kg and31.8mg/kg at rich level.