不同植物组合对煤矸石混合土中镉的吸收效应

Effect of Different Plants Combinations on Cadmium Uptake Grown in a Mixed Matrix of Coal Gangue Weathered Material and Soil

煤矸石是煤炭开采和利用过程中产生的废弃物,堆放的煤矸石风化物镉含量高,易造成邻近水体和土壤污染,利用植物修复煤矸石重金属污染已成为研究热点。本文采用盆栽模拟试验方法,将煤矸石风化物与土壤以1︰1混合作为培养基质,比较黑麦草、菊苣、紫花苜蓿单作与间作条件下的生长状况,以及植株氮、磷、镉含量和吸收量等,以期筛选出适合煤矸石镉污染修复的植物组合。结果表明,单作条件下黑麦草在煤矸石混合土壤上生物量最大,但其镉吸收量与菊苣、苜蓿无显著差异;间作提高了黑麦草生物量、氮、磷和镉的吸收量,降低了菊苣的生物量、氮、磷和镉的吸收量,间作对苜蓿的影响不明显;6种植物组合中,黑麦草与苜蓿间作植物地上部生物量、氮、磷和镉吸收量均最高,其中镉吸收量是其它组合的1.29~1.76倍,可作为修复煤矸石重金属镉污染的优质组合。

Coal gangue with high cadmium （Cd） content is an inevitable product from the process of coal mining. The abandoned coal gangue could cause Cd contamination to the adjacent water and soil. Phytoremediation of heavy metals contamination has become a research hotspot. Using a mixed matrix of coal gangue weathered material and soil （w/w, 1：1） as cultivation medium, a pot experiment was conducted to investigate Cd uptake by ryegrass, chicory, and alfalfa in monoculture or intercropping. The results indicated that ryegrass biomass in monoculture was the largest, but with no significant different for Cd uptake compared with chicory and alfalfa. The biomass and nitrogen, phosphorus, Cd uptake by ryegrass significantly increased after intercropping with chicory or alfalfa. While the significant decrease and no significant change were observed for chicory and alfalfa, respectively. Among all treatments, ryegrass intercropping with alfalfa has the highest aboveground biomass and the uptake of nitrogen,phosphorus, and Cd. Especially, the Cd uptake was 1.29-2.76 times of other planting combinations. Ryegrass intercropping with alfalfa as the optimal planting combination could be used into the remediation of Cd contamination in coal gangue.