江苏沿江地区20年来农业土壤资源缩减特征

CHARACTERISTICS OF AGRICULTURAL SOIL RESOURCES REDUCTION IN THE REGION ALONG THE YANGTZE RIVER OF JIANGSU PROVINCE IN THE LAST TWO DECADES

在遥感和地理信息技术支持下，对江苏沿江地区1984-2003年城镇扩张侵占农业土壤资源的特征进行了研究。结果表明，1984-2000年，江苏沿江地区农业土壤资源缩减主要围绕重要城市，缩减图斑面积大，且区域分布相对平衡。2001～2003年，农业土壤资源缩减速率显著增快且各地市呈不平衡发展，除南京外主要集中在常州、江阴、泰兴、常熟地区。20年来江苏沿江地区农业土壤资源缩减了8．91％，缩减面积达到190713hm^2，所有土壤类型均受到城镇扩张影响，其中水稻土被侵占的面积最大。该区域农业土壤资源按肥力质量可分为5等，1984～2000年，Ⅰ～Ⅴ等土壤资源受城镇扩张影响程度依次降低。2001～2003年，Ⅰ、Ⅲ等土壤资源受城镇扩张影响程度明显降低，而Ⅱ、Ⅳ、Ⅴ等土壤资源受城镇扩张影响程度增加，按受影响程度排序变为Ⅴ、Ⅱ、Ⅳ、Ⅲ、Ⅰ。

With the aid of RS and GIS techniques, the characteristics of agricultural soil resources reduction caused by urban expansion was studied during 1984-2003 in the region along the Yangtze River of Jiangsu Province. The results indicated that during 1984-2000,agricultural soil resources in the region along the Yangtze River of Jiangsu Province mainly reduced around center urbans and the area of occupied soil was big and its spatial distribution was relatively equal. However during 2001-2003,agrieultural soil resources in this region decreased faster and showed a large disproportion among cities. In this period, the agricultural soil resource reduction was mainly concentrated on Changzhou county,Jiangyin county,Taixing county and Changshu county, except for Nanjing city. From 1984 - 2003 the quantity of agricultural soil resources decreased by 8. 91% and the total reduced area of agricultural soil resources was 190 713 hm^2. All types of agricultural soil showed a decreasing trend in quantity, among those paddy soils was largest in area reduction. The soil resources in this region were divided into 5 classes according to fertility quality. The influence extent of urban expansion on agricultural soil resources of Ⅰ -Ⅴ classes was lowering successively during 1984-2000. However during 2001-2003 the order was Ⅴ ,Ⅱ, Ⅳ ,Ⅲ, Ⅰ because the influence extent of urban expansion on agricultural soil resources of Ⅰand Ⅲ classes obviously decreased and that of Ⅱ, Ⅳ and Ⅴ classes increased.