| As human beings has walked into the21century, not only have problems such as population, resources, environment etc. not been solved, but also the problems are becoming more and more severe day by day. The total farmland of our country stands only1/3in the world in aera, while it has to feed1/4of the population all over the world which makes the contradiction between human being and farmland much sharp. In the pace with the quick development of the economy in Liuhe District, Nanjing City and the accelerating of industrialization and urbanization, a large amount of farmland has been embezzled and affected by both industrial point source and agricultural non-point source which has made the farmland productivity decreased in different degrees. It has brought hidden danger to agricultural production, agricultural product quality and food security. To understand farmland productivity and quality comprehensively, promote the strategic adjustment of agricultural structure, speed up the quality of agricultural products, raise the overall production capacity of arable land and keep the sustainable development of agriculture, the comprehensive survey and evaluation are needed as soon as possible.In this paper, Liuhe District, Nanjing City was the study area and the evaluation of the soil fertility of cultivated land was the research object. We owned county land resource management information system software as application platform, using GIS technology to process and integrate a variety of attribute data and spatial data; using overlaid land-use maps and soil maps to form evaluation units; selecting13factors which are related to the farmland’s natural elements as evaluation factors; using the mathematical analysis ways such as correlation analysis, factor analysis, fuzzy evaluation, hierarchical analysis etc. to make structural hierarchies, establish an evaluation factor model and calculate the weight of each factor to set a farmland evaluation method which combined qualitative with quantitative.The study investigated4033farmers, collected3464grain and oil field samples,71soil samples of vegetable land,246tea garden samples,112fruit garden samples and140 seedling land samples. Mainly based on the IFI, the evaluation took the method---cumulative frequency curves, to divide the farmland of Liuhe District into6levels, using the software Arcview to operate the library of evaluation chart attributes, search and statistic various grades of cultivated land area and map sites in the area, then get the area of each level.The result showed that the farmland area of Liuhe District was divided as follows:the1level is2477.12Ares, stands5.2%in the total area; the2level,5467.21Ares, stands11.5%of total area; the3level,16691.38Ares, stands35.1%; the4level,10990.01Ares, stands23.1%; the5level,9313.05Ares, stands19.6%; the6level,2688.64Ares, stands5.6%of the total area.The result of the study showed that the division of fertility levels and the determination of each level’s proportion were scientific and objective. The evaluation result reflected the fertility of cultivated land within the study area much accurately which was broadly in line with the objective reality of Liuhe. It meant that the method in this study was viable and scientific in the evaluation of Farmland Productivity. At the same time, the evaluation result told us that the overall standards of the farmland productivity in Liuhe were in a middle level, the proportion of high yielding land and middle-low yielding land was very low which also provided a scientific basis in the alteration and improvement of low-grade cultivated land in Liuhe. At the same time, the result of farmland productivity evaluation provided a scientific basis in the applying of Equilibrium Fertilization Technology to fertilize farmland productivity. |
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