太湖地区不同土地利用影响下水稻土重金属有效性库变化

在太湖地区调查选择了乡镇工业环境、集约化农业丰产方及长期肥料试验地等几种人类农业利用类型和环境影响的地块,采集水稻土耕层样本作若干重金属的有效性库分析.结果表明,各种环境和利用影响下太湖地区水稻土重金属有效性库都存在升高的趋势,其程度介于30%至200%,且以表层最为突出.近工业区环境和长期单施化肥下这种有效性库变化最为剧烈,其土壤Cu、Pb有效性库分别达到7.96～2.15 mg·kg^-1、24.7～3.47mg·kg^-1和8.34～4.42 mg·kg、9.01～4.95 mg·kg^-1.这种有效性升高伴随着总量的积累趋势可能是太湖地区土壤环境质量演变的当前特点,这必须在本地区农业与食物安全中备加关注.

Change of Available Pool of Heavy Metals in Paddy Soils Under Human Land Use Impacts from the Taihu Lake Region, Jiangsu Province, China

A number of representative farms under various human land uses were selected through a general survey in the Taihu Lake region, Jiangsu Province, China. The land uses covered vicinity of smelt industry and township industry, long history of high-yielding performance, long term fertilization treatments. Top layers of the paddy soils were sampled for analysis of available pool of heavy metals. A prevalent trend of increasing availability was observed of heavy metals by a degree of 30% up to 200% in the soils under these human impacts as compared with that under relative conserved conditions. This increasing trend was most remarkably exhibited in the top sub-layer of the paddy soils. The highest rise of the available pool largest was found in those under smelt industry impact and under long term chemical fertilization alone. The result showed that available pool of surface soil Cu and Pb under these impacts were 7.96-2.15 mg.kg-1, 24.7-3.47 mg.kg-1 and 8.34-4.42 mg.kg-1, 9.01-4.95 mg.kg-1 respectively. The dramatic rise of the availability with the increasing trend of the total (as previously reported) might stand for contemporary soil environmental quality and, thus, require severe concerns for agriculture and food security in this rapidly developing region.