The Evaluation And Classification Of Cultivate Land Fertility In Zhangjiagang

The cultivated land is the basic resources and conditions for human beings,without which people could not live.Unfortunately,the area of cultivated land gradually reduced with the increasing of population quantity and economic level.While ensuring the area and quality of cultivated land is the precondition to maintain the agricultural sustainable development.And consequently it is very important to carry out the evaluation of cultivated land fertility,through which we could understand the quality,area and distribution of the existing cultivated land more effectively.Meanwhile the evaluation and classification of cultivated land fertility also have important meaning for the adjustment of agricultural structure,assurance of national food security and advancing agricultural sustainable development.In this research,we evaluate the cultivated land fertility of Zhangjiagang in Jiangsu province,based on the data which was collected and sorted.The environment survey soil,soil fertility survey and irrigation water were sampled,and thirty-five impact factors were measured in this study.The evaluation and classification of cultivate land fertility in Zhangjiagang were carried out by Delphi method,Analytic Hierarchy Process and fuzzy mathematic math The results showed that the cultivated land of Zhangjiagang could be divided into four levels and third level and second level are mainly level,in which,the area of third level,second level,and forth level cultivated land accords to 27.37%,69.64%and 2.80%of the total arable cultivated land,respectively.Generally,the soil fertility levels of most cultivated land in the city were middle or high.From the results of soil fertility evaluation in 1980 and 2008,it could be found that the soil fertility of cultivated land were mainly third level and forth level in 1980,while were mainly third level and second level in 2008.This result showed that the soil fertility of cultivated land in Zhangjiagang raised a level from 1980 to 2008.Through the comparative analysis of factors including soil organic?total phosphorus?effective phosphorus?available potassium?slowly available potassium?effective zinc?thickness,and pH value during the evaluation in 1980 and 2008,result showed that all the evaluation factors had been raised or keep balance,excluding the decreasing in slowly available potassium and pH value.This result confirmed the increase of the soil fertility of cultivated land in Zhangjiagang.Based on these results,we proposed several measures such as increasing application of organic fertilizer,balanced fertilization technology,flat farmland productivity construction,cultivated land quantity and quality management,preventing environmental pollution of cultivated land irrigation water and soil.