| Cultivated land is a precious part of land and the basic source for agricultural production. It is an important substance element which human being relies on to live and develop. The quality of cultivated land affects the sustainable development of agriculture and food security directly. Zhuzhou County located in Hunan province, the xiangjiang midstream and has good agricultural foundation. The fertility of the soil and the quality of cultivated land has changed a lot since the second national soil survey. Therefore, soil classification system and Characteristics of Soil Fertility are studied by the methods of field investigation, laboratory analysis, mathematical model, "3S" technique in Zhuzhou County, Hunan Province from 2007. The contributions of this dissertation are as follows:1) Soil of Zhuzhou County includes 4 types:the paddy soil, moisture soil, redearth and purple soil,9 subclass,38 soil genus and 95 soil species. Paddy field is in majority and widespread, all of which is the paddy soil. Its area is 24 445.13hm2, accounting for 84.62%of the total area of cultivated land. The paddy soil contains 4 subclass,27 soil genus and 78 soil species. The redearth is in majority and its area is 3321.1 hm2, accounting for 84.62%of the total area of dry land. The paddy soil contains 2 subclass,5 soil genus and 12 soil species.2) Basing on the evaluation principles, a indicator system of Zhuzhou county soil capability assessment was established, which including:topography sites, soil available Phosphorus, texture, organic matter, obstacle factors, slowly available Potassium, discharge ability, irrigate ability, Structure Profile, thickness of Topsoil layer. Using fuzzy comprehensive evaluation model, the result showed that the farmland productivity level of Zhuzhou County is in middle level. Its mainly level was sixth grade, the second grade and fifth grade. And the sixth, the second and the fifth grade accounts for 21.38%,17.98%, and 17.72%of the total area of cultivated land, respectively. Cropland of the low yield spread almost every town.3) Through the evaluate result of cultivated land in Zhuzhou county statistically analyzed with the single factor, the results showed that the mainly restricting factors of farmland productivity of Zhuzhou are slowly available potassium, thickness of Topsoil layer and soil texture. Potassium index is low in every grade land.4) There are 7286hm2 low-yield fields,12721 hm2 medium-yield fields and 8879 hm2 high-yield fields. The area of low-yield and medium-yield field is more than high-yield field; accounting for 69.26% of the total area of cultivated land.The high-yield field maintenance can be achieved by fertilization. The low-yield field can be improved by engineering measures, biological measures, agricultural measures and Chemical measures. |
