4种改良剂对土壤-黑麦草系统中镉行为的影响

以黑麦草（Lolium perenne L.）作为修复植物,开展了石灰、磷灰石、木炭、猪粪4种改良剂对重金属Cd污染土壤的田间原位修复试验研究。结果表明：改良剂提高了土壤pH值并促进土壤Cd从生物可利用性高的形态向迟效态转化,降低对生物和环境的直接毒害作用,促进黑麦草的生长。以黑麦草生物量和Cd富集量的增加作为评价指标,4种改良剂修复Cd污染土壤效果依次为：石灰〉磷灰石〉木炭〉猪粪。石灰处理中黑麦草Cd富集量为13.11 mg,与其他处理均呈现显著差异。污染土壤重金属Cd的化学形态与黑麦草对Cd的吸收密切相关。黑麦草地上部分Cd质量分数,与土壤B-2态Cd呈极显著正相关关系,相关系数为0.730。黑麦草地下部分Cd质量分数,与B-2、B-3态Cd均呈极显著正相关关系,相关系数分别为0.756、0.786;黑麦草地上部分和地下部分Cd质量分数均与B-4态Cd呈极显著负相关关系,相关系数分别为0.757和0.708。

Effects of four amendments on behaviors of cadmium in soil-ryegrass system

In this paper,four amendments,including lime,apatite,charcoal,and pig manure,were applied in a Cd contaminated filed,and ryegrass（Lolium perenne L.）was planted for in-situ soil remediation.The results show that these amendments not only increased soil pH but also promoted the transformation of Cd from active forms to inactive ones.These amendments have the ability to decrease the soil Cd toxicity in the order of lime apatite charcoal pig manure.The quantity of Cd bioaccumulation in ryegrass is 13.11 milligram as lime was applied,which is significantly different from the other treatments.Ryegrass Cd uptake depends on soil Cd fractionations.Shoot Cd concentration is positively correlated with B-2-Cd in soil,and the correlation coefficient is 0.730（P0.01）.Root Cd concentration is positively correlated with B-2-Cd（r=0.756,P0.01） and B-3-Cd（r=0.786,P0.01） in soil.But,the shoot and root Cd concentrations were negatively correlated with B-4-Cd in soil with correlation coefficient of 0.757 and 0.708,respectively.