| The arable land is related to national food security, food safety, and light industrial development and it is of great significance social stability and the health of the national and economic development. When domestic arable land is difficult to increase, soil degradation, pollution-prone background, to improve the fertility of arable land and the level of quality both for the country or region is important practical significance.Changjiang is an industrial county that is located in Hainan northwest. It is very important to develop high-efficiency tropical agriculture when the mineral resources increase depletion. Therefore, the thesis is with Changjiang County as the study area and research the Farmland preliminary evaluation with the ArcGIS9.3, Access2007software and the use of fuzzy mathematics and analytic hierarchy. The main results are the following.(1) The study has established Changjiang County arable land resources information database and Changjiang County, arable land fertility evaluation index system, and vector-based data structure further completed Evaluation of Arable land; accumulated experience of Arable land Productivity Evaluation in Changjiang.(2) The statistical results of Changjiang nutrients in cultivated soils show that soil total nitrogen, nitrogen, potassium and effective average sulfur content is very low, which is0.54g/kg,54.49mg/kg,51.25mg/kg and15.55mg/kg respectively. the average content of soil organic matter and exchangeable magnesium is lack withl5.12g/kg and71.38mg/kg; the average content of available phosphorus is13.24mg/kg, in the middle and lower level; the average content of exchangeable Ca, Cu, zinc is higher with875.88mg/kg,1.83mg/kg,1.22mg/kg; the soil pH average of5.88, at a weak acid level.(3) The spatial analysis of soil nutrient of Changjiang arable indicated that the distribution of nutrients is significant differences in cultivated soils of different regions. The soil nutrients of Changhua and Haiwei in northwest coast is lack, for example the soil organic matter and total nitrogen, potassium, exchangeable calcium/magnesium is very low. The effective zinc and available phosphorus of Wulie in inland is relative lack. The soil nutrient content in central hilly area is relatively higher.(4) Compared with the second national soil survey, the soil potassium, nitrogen content in Changjiang decreased significantly, and soil organic matter content also declined, little change in the average content of soil available phosphorus, but increasingly uneven distribution. (5) According to the force evaluation index, the arable land of Changjiang is divided into five grades. The total area of the first grade is about1445.42ha, accounting for9.13%of the total arable land, which mainly concentrated in the north of the barracks of Hong Ling area and southern Hongyang, ginger Park. The total cultivated area of second grade is5687.25ha, accounting for35.90%of the total area of arable land, which mainly distributed in the central and western arable land a peripheral area. The total arable land area of the third grade is5064.80hectares, accounting for31.97%of the total area of arable land, which mainly in the central and western regions, mixed with other levels of arable land located in the alluvial plain area. The total arable land area of the fourth grade is2335.65ha, accounting for14.75%of the total area of the county’s arable land, which mainly distributed in the lower level along the Coastal Plain terrain. The arable land area of the fifth grade is1306.89ha, accounting for8.25%of the total arable land,which mainly in the western alluvial plain area which the irrigation is relatively poor.(6) The results of Evaluation of Arable land clarify the main factors affecting the Arable land of Changjiang County; the results also identify and analyze the existing problems in arable land Use of Changjiang County which can propose measures recommended Changjiang arable land sustainable use of resources. |
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