| Cultivated land is the essence and irreplaceable resource for agricultural production and it is also the important resource for sustainable development of our society and national economy. Protection of arable land is one of our basic national policies; therefore, it is of great significance to know the quantity, quality and changes of cultivated land for the reasonable planning, utilization and effective protection of cultivated land. Two soil investigation tasks were carried out in 1959 and 1979 respectively in Zhangqiu. During the twenty years, urban and rural economy have changed greatly, and then based on past data to guide the current agricultural production has lost meaning. Therefore, to make new land capacity, environmental investigation and evaluation and understand the current quality of cultivated land resources, the development of modern agriculture, increasing the number of agricultural products, improving quality of agricultural products, soil-point source pollution prevention and control, optimizing agricultural production, reduce production costs, and effectively effectively improve the efficiency of agricultural production, has a pivotal roleAs a result, to understand the fertility and quality of cuitivated land and take exelusive measures to improve comprehensive productive capacity by launching regional investigation and evaluationon culiivated land fertility is of great realistic significance food security and promoting sustainable development of regional agricultural as well as our economical society.We used GIS, GPS and spatial interpolation techniques to carry out a comprehensive analysis of field investigation and laboratory testing work. We investigated and sampled in 6 Zhangqiu subdistrict offices, 11 towns, 3 townships 7.62 hectares of arable land successively. There are 536 distribution points and a total of 858 samples including 98 soil samples taken from subsoil, 136 soil samples taken from environmental survey, 87 water samples; 1 plant sample. There are a total of 24,384 items about laboratory analysis on soil organic matter, total nitrogen, phosphorus, potassium, slow potassium, exchangeable calcium, exchangeable magnesium, available S, Zn, Cu, Mo efficient, effective iron, boron, Mnand pH, soil bulk density, heavy metal, BHC, DDT and other 32 projects. In addition, we investigated 536 farmers and their production in accordance with the requirements of detailed investigations and got first-hand information and obtained the detailed data through systematic analysis.This evaluation can be divided into three main contents: Fistly, tools preparation and databases establishment: According to the evaluation, mission, scope, methodology, we Prepare and evaluate all of the natural and socio-economic data to deal with the data .Selectting the appropriate computer hardware and analysis software such as GIS and establishing the basic database of evaluation farmland. Secendly, soil fertility assessment. Setting off the evaluation units, extracting the key factors of soil fertility and making the weight, selecting the appropriate evaluation methods, developping evaluation criteria and determining the grades of cultivated land fertility. Thirdly, evaluation results analysis. According to the evaluation results, calculating the cultivated area, draw up the distribution of soil fertility maps, analyzing the soil fertility problems and then proposing measures for the sustainable use of land resources.The building of evaluation index system is based onin strict compliance with the investigation and evaluation of land quality principles, methods and the quality of cultivated land in accordance with the Ministry of Agriculture investigation and evaluation procedures and grading standards, combined with local conditions, selecting a greater impact on soil fertility (such as slope position, irrigation and drainage conditions, etc.), significant variation within the region (such as slope, soil effective thickness, etc.), in the time series are relatively stable (such as soil texture, organic matter content, etc.), and agricultural production (related to factors such as climateetc.) of the 11 factors.Through comprehensive analysis, we divided the city's land into 5 grades using the fuzzy comprehensive evaluation method and taking the polygons which includes the 1:50000 map of cultivated soil and the land use map as the evaluation units.The first grade land, its comprehensive evaluation index is more than 0.894 and the cultivated land is 32498.62hm2, accounted for 42.72% of total arable land area is the largest area in Zhangqiu city. The irrigated farmland is 24598.44 hm2, dry one is 7405.43 hm2, vegetable is 342.99 hm2, accounting for 75.69%, 22.79%, 1.06% of the first grade land respectively. In addition, there are a little of irrigated paddy fields.The second grade land, it's the comprehensive evaluation index is 0.853-0.894 and the cultivated land is 32498.62 hm2, accounted for 24.55% of total arable land area is the largest area in Zhangqiu city. The dry farmland is 7405.43 hm2, the irrigated one is 6728.26 hm2, the vegetable is 6728.26 hm2, accounting for 61.94%, 36.03%, 1.30% of the second grade land respectively, In addition, there are a little of Irrigated paddy fields .The third grade land, whose comprehensive evaluation index is 0.813-0.853 and the cultivated land is 18009.2 hm2, accounted for 15.61% of total arable land area is the largest area in Zhangqiu city. The dry farmland is 8814.31 hm2, the irrigated one is 2681.34 hm2, accounting for 74.24%, 22.58%of the third grade land respectively, In addition, there are a little of Irrigated paddy fields and vegetable land.The fouth grade land, whose the comprehensive evaluation index is 0.764-0.813 and the cultivated land is 9027.89 hm2, accounted for 11.87% of total arable land area is the largest area in Zhangqiu city.The dry farmland is 8440.96 hm2, the irrigated one is 582.77 hm2, accounting for 93.50%, 6.46% of the fouth grade land respectively, It can be said that the most is dry land, in addition, there are a small amount of vegetable one.The fifth grade land, it's comprehensive evaluation index is less than 0.764 and the cultivated land is 3998.13 hm2, accounted for 5.26% of total arable land area is the largest area in Zhangqiu city. The dry farmland is 3997.18hm2, accounting for 99.98% of the fifth grade land. In addition, there are a little of irrigated fields.Through this analysis and investigation, we basieally have been made three cultivated type regions by soil nutrient content and scope of classification.On this basis we propose the following suggestions: rational allocation of land resourees,crop structure adjustment,the quality of the establishment of a farmland protection and nurturing of grip incentive mechanism,strengthen the monitoring of soil fertility and quality of dnalmic management,the establishment of a farmland quality management of long-term mechanism.
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