不同草本植物间作对Cd污染土壤的修复效果

为了研究不同草本植物间作对空心菜Cd吸收效果及污染土壤中Cd移除率的影响，采用盆栽试验，以空心菜茎叶Cd消减率与土壤中Cd移除率为主要指标，研究了空心菜在Cd污染土壤中单作及与10种草本植物（高丹草，苏丹草，狼尾草，黑麦草，苦卖菜，菊苣，籽粒苋，三叶草，紫花苜蓿，紫云英）间作的Cd积累效应与对Cd污染土壤的修复效果.结果表明：不同间作处理对空心菜茎叶与根中Cd含量有显著影响，其中，空心菜与高丹草、苏丹草、狼尾草间作后，空心菜茎叶Cd含量显著降低，空心菜茎叶Cd的消减率分别达到34.0%、35.8%、34.3%；菊苣、籽粒苋、三叶草、紫花苜蓿及紫云英与空心菜间作对空心菜茎叶Cd吸收有不同程度促进作用.间作的不同草本植物对土壤中Cd的吸收间有显著差异，地上部Cd含量范围1.81~12.87mg/kg，最大相差7.1倍；不同间作植物茎叶中Cd含量大小为：苦荬菜 > 菊苣 > 苏丹草≈黑麦草 > 高丹草≈狼尾草 > 紫花苜蓿≈籽粒苋 > 三叶草≈紫云英.不同草本植物与空心菜间作对土壤Cd移除率为0.35%~1.49%，其中，高丹草、苏丹草、狼尾草对土壤Cd的移除率分别达到1.46%、1.49%和1.48%；高丹草、苏丹草、狼尾草间作不仅可以有效降低空心菜Cd含量，同时对污染土壤中Cd具有较高的移除率，在Cd污染农田土壤的间作修复中具有较好的应用价值.

Remediation efficiency of Cd polluted soil by intercropping with herbaceous plants

A pot experiment was conducted to evaluate the effect of intercropping with different herbaceous plants on the uptake and transfer of Cd by water spinach as well as the remediation efficiency of Cd polluted soil. In this study, ten different herbaceous cultivars i.e. Gaodan grass, Sultan grass, Pennisetum, Ryegrass, Bitter vegetables, Chicory, Grain amaranth, Alfalfa, Clover and Vetch were used as intercropping plants, Cd accumulation by water spinach and remediation efficiency were mainly evaluated by the removal rate (%) of Cd in edible part (shoots) of water spinach and removal rate (%) of Cd from polluted soil. The results showed that significant differences (P<0.05) of shoot and root Cd content of water spinach were observed between the intercropping treatments. Among the treatments, the shoot Cd content was significantly decreased by Gaodan grass, Sultan grass and Pennisetum intercropping, the Cd decrease rate (%) reached 34.0%, 35.8% and 34.3% respectively, however, the uptake of Cd by water spinach was promoted with intercropping with Chicory, Grain amaranth, Alfalfa, Clover and Vetch resulting in increased shoot Cd content. Significant difference of the uptake and transfer of Cd by herbs was also observed in this study, the shoot Cd for herbs ranged from 1.81mg/kg to 12.87mg/kg, with a maximum variation of 7.1folds, the shoot Cd content of the tested herbs followed the order of Bitter vegetables > Chicory > Sultan grass≈Ryegrass > Gaodan grass ≈Pennisetum > Clover ≈ Grain amaranth > Alfalfa ≈ Vetch. The removal rate (%) of Cd from the soil ranged from 0.35% to 1.49% among the treatments. The removal rate (%) of Cd from the soil for the intercropping with Gaodan grass, Sultan grass, Pennisetum reached 1.46%, 1.49% and 1.48% respectively. Intercropping with Gaodan grass, Sultan grass, Pennisetum can not only effectively reduce the Cd uptake by water spinach, but also remove Cd from polluted soil with high efficiency. In conclusion, Gaodan grass, Sultan grass and Pennisetum have great potential application for the intercropping treatment for remediation of Cd polluted field soils.