晋北大同盆地土地生态安全评价中的土壤Se指标

通过对大同盆地土壤Se含量水平的调查和160组玉米籽实与根系土Se含量关系的研究发现:①大同盆地土壤Se含量一般在100～200 ng/g之间,平均值为152 ng/g;②玉米籽实Se含量对土壤Se全量、水溶态Se含量、离子交换态Se含量、碳酸盐态Se含量均具有很好的响应关系,在统计学上印证了植物中的矿质营养元素主要来自土壤和土壤溶液;③土壤全量Se可以作为土壤质量评价的重要指标之一,建议大同盆地土壤缺Se和土壤富Se的评价标准值分别为180 ng/g、360 ng/g;④大同盆地研究区内大面积缺Se和富Se的土壤仅分布在浑源县和朔州东部滋润一带。

Indicator of selenium in soils for land ecological security assessments in the Datong basin, northern Shanxi, China

Geochemical investigation of Se concentrations in softs in the Datong basin and study of the relation of the selenium con- centration of 160 groups of maize grain and that in its rhizosphere softs indicate that:(1) the selenium concentration of top softs in the Datong basin generally ranges from 100 to 200 ng/g,with an average of 152 ng/g,;(2) the selenium concentration of maize grain had a reasonable correspondence with the total concentration of selenium and concentrations of water-soluble,ion-exchange and carbon- ate Se species in top softs,which statistically verifies the hypothesis that the mineral nutrient elements in plants are mainly derived from softs and solutions in softs;(3) the total concentration of selenium in top softs may serve as one of the important indicators for soft envi- ronmental quality assessments and it is proposed that the standard values for assessments of selenium deficiency and sufficiency be 180 ng/g and 360 ng/g respectively;and (4) soils in which selenium is extensively deficient or sufficient in the study area of the Datong basin are distributed only in Hunyuan County and the east of the Shuozhou area.