长三角典型区占补耕地土壤肥力的时段特征

Temporal characteristics of soil fertility of cropland requisition-compensation in the typical region of Yangtze River Delta,China

基于1984、2000和2016年卫星遥感影像,分析了江苏省常熟市耕地占补时空变化特征;基于Arc GIS和土壤采样数据,利用隶属度函数综合法评价了1984和2000年耕地土壤肥力;采用叠加分析,揭示了1984—2000、2000—2016年间该地区占补耕地土壤肥力特征.结果表明:1984—2016年间,常熟市耕地面积减少了1/3,1984—2000年被水域和居民点工矿用地分别占用了51.7%和41.4%,2000—2016年只居民点工矿用地就占用了80.8%.1984—2000年间,常熟市耕地土壤肥力上升的面积占65.5%,仅3.9%下降;南部地区土壤肥力均高于其他地区.研究期间耕地数量和质量占补不平衡,前时段"占多补少、占优补劣"形势严峻,后时段"占多补少、占劣补劣"特征明显.耕地减少的趋势并未扭转,异地补充明显,耕地占补平衡应当关注异地补充耕地质量和土壤肥力时段性特点.

Based on the satellite image in 1984, 2000 and 2016, we analyzed the temporal and spatial variation of cropland requisition-compensation in Changshu City, Jiangsu Province. Based on ArcGIS and the data of soil samples, membership function with integrated fertility index were used to evaluate the soil fertility in 1984 and 2000, respectively. The overlay analysis had been used to reveal the characteristics of soil fertility of cropland requisition-compensation between the period of 1984 to 2000 and 2000 to 2016. Results showed that the cropland reduced by 1/3 from 1984 to 2016, which was occupied by water area （51.7%） and residential, industrial and mining land （41.4%） between 1984 to 2000, while between 2000 to 2016 cropland was occupied dominantly by residential, industrial and mining land （80.8%）. The soil fertility of in 65.5% of the total area of Changshu increased while the decreasing part just accounted for 3.9% from 1984 to 2000. At the same time, soil fertility was higher in the south area of Changshu City than other area. The quantity and quality of cropland requisition-compensation were not balanced, with the serious status of occu- pying more cropland but replenishing less, occupying fertile cropland and replenishing poor one in former period, and occupying more cropland and replenishing less, occupying poor cropland and replenishing poor one in the later period. The trend of cropland shrinking had not been altered, and the cropland compensation in different places was epidemic. The quality of cropland compensation in different places and the temporal characteristic of soil fertility should be highlighted for the balance of cropland requisition-compensation.