潮土重金属复合污染对紫花苜蓿的影响

本文依据我国土壤环境质量标准确定潮土中重金属（铜、锌、镉）复合污染物的不同浓度，通过正交设计的盆栽试验观测紫花苜蓿的生物量、植株体中重金属含量、土壤中重金属有效态含量等指标分析重金属复合污染对紫花苜蓿生长的影响。结果表明，当土壤中供试的各重金属浓度为我国土壤环境质量二级标准水平时，紫花苜蓿的生长不受重金属的胁迫作用；当土壤中重金属铜、锌浓度均达到三级标准水平时，紫花苜蓿的生长才受到明显的抑制作用。说明我国土壤环境质量标准对潮土上紫花苜蓿的生长基本适用。在复合污染条件下，铜、锌之间存在明显的抑制作用，同时土壤中重金属有效离子冲量能较好地表征紫花苜蓿－潮土中重金属复合污染的影响。

Impacts of heavy metals contamination in fluvo-aquic soil on alfalfa

Pot experiments with orthogonal design have been conducted to study the impacts of heavy metals contamination (copper, zinc and cadmium) in fluvo-aquic soil on alfalfa growth. The heavy metal concentrations of the test soil are based on the Chinese Soil Environment Equality Standard (CSEES). The biomass and the total heavy metal contents of alfalfa and the available heavy metal concentrations of the test soil have been determined. The results indicate that heavy metals stress has little effects on the growth of the alfalfa when the concentration of the test soil is under the second level of CSEES, and there is evident stress on the growth of the herbage when heavy metals concentration reaches the third level. So CSEES is appropriate to the alfalfa growth in the test soil. There is evident antagonism between copper and zinc under the combined contamination. The soil available ion impulse is the appropriate method to evaluate the correlation of the heavy metal between the alfalfa and fluvo-aquic soil.