植物套作系统修复镉污染农田土壤的效应——以苏南地区为例

Effect of plant intercropping system on remediation of cadmium contaminated farmland soil-A case study on the southern Jiangsu province area

为了研究不同套作模式对苏南地区Cd污染农田土壤的修复效果,选用能在苏南地区生长的伴矿景天、东南景天、苋菜和龙葵4种Cd超富集植物与大豆、油菜和小麦3种常规作物在Cd污染农田土壤中进行单作和套作修复试验.结果显示,与油菜套作后,4种超富集植物的Cd吸收量均有所增加,其中东南景天增幅最大,地上部Cd含量比单作增加24.4%;与小麦套作后,东南景天对Cd的吸收有所增加,地上部Cd含量比单作增加2.75%,龙葵和苋菜对Cd的吸收变化不显著,说明与油菜和小麦套作均能促进东南景天对Cd的吸收.套作伴矿景天减少了大豆根部Cd含量,套作苋菜和龙葵显著降低大豆茎、叶部分的Cd含量;套作模式下油菜根、茎的Cd含量均显著降低,叶片Cd含量受套作影响不显著;套作均显著降低了小麦的Cd含量,表明套作能抑制作物对Cd的吸收.此外,东南景天-油菜模式下Cd总积累量和土壤Cd去除率最高,为1343μg/盆和16.4%;东南景天-小麦次之,为1053μg/盆和9.8%.因此,东南景天-油菜/小麦两种套作模式均是苏南地区Cd污染农田土壤的适宜植物套作修复模式.研究结果可为该地区Cd污染农田修复同时安全利用提供科学依据和技术支持.

In the study,soybean(Glycine max(L.)Merr.),rape(Brassica napus L.)and wheat(Triticum aestivum L.)were used as the subjects,intercropped with Cd hyperaccumulators,i.e.Sedum plumbizincicola,Sedum alfredii,Amaranthus tricolor L.and Solanum nigrum L.,to investigate the remediation effects of various intercropping patterns on Cd polluted farmland soil in southern Jiangsu Province.The findings revealed that intercropping with rape,the Cd concentrations in the hyperaccumulator plants were enhanced,among which Sedum alfredii increased the most,and the Cd concentrations in aboveground parts increased by 24.4%compared with monoculture.After intercropping with wheat,Cd concentration in Sedum alfredii was increased,the Cd concentrations in aboveground parts increased by 2.75%compared with monoculture,but the Cd concentrations of Solanum nigrum and Amaranthus tricolor did not change significantly,indicating that intercropping with rape or wheat could promote the absorption of Cd by Sedum alfredii.Intercropping with Sedum alfredii decreased the Cd concentration in soybean roots,and intercropping with Amaranthus tricolor and Solanum nigrum significantly decreased the Cd concentration in soybean stems and leaves.Under the intercropping mode,the Cd concentration of rape roots and stems decreased significantly,and the Cd concentration of leaves was not significantly affected by intercropping.Intercropping significantly reduced the Cd concentration of wheat,suggesting that intercropping could inhibit the absorption of Cd by crops.The total accumulation of Cd and the removal rate of Cd in soil under Sedum alfredii-rape model were the highest,which were 1343μg/pot and 16.4%.Sedum alfredii-wheat was the second,with 1053μg/pot and 9.8%.In summary,the intercropping pattern of Sedum alfredii-Brassica napus/Triticum aestivum were the suitable model.This study screens out a plant intercropping remediation model suitable for Cd-contaminated farmland soil in southern Jiangsu province area and provide technical support for both safe production and remediation of Cd-contaminated farmland soil in the region.