Cd对我国不同类型土壤硝化活性影响的主控因子研究  

Main factors affecting the toxicity of Cd by soil nitrification activity

作　　者：谭向平[1] 王紫泉[1] 张晶[1] 和文祥[1,2] 韦革宏[3] 

机构地区：[1]西北农林科技大学资源环境学院,杨凌712100 [2]农业部西北植物营养与农业环境重点实验室,杨凌712100 [3]西北农林科技大学生命科学学院,杨凌712100

出　　处：《环境科学学报》2016年第7期2624-2630,共7页Acta Scientiae Circumstantiae

基　　金：国家自然科学基金项目(No.41571245);国家高技术研究发展计划项目(No.2012AA100602);西北农林科技大学"基本科研业务费科研创新重点项目"(No.ZD2013012);国家公益性行业(农业)科研专项(No.200903015)~~

摘　　要：硝化作用是土壤中存在的一个重要生物学过程,其对环境条件的变化表现出极高的敏感性,其中包括重金属污染.本文选取我国10种不同类型土壤,采用室内模拟方法,研究硝化活性对不同Cd污染程度的响应特征以及影响Cd毒性的主要控制因素.结果表明:除红壤和黑土外,土壤硝化活性随外源Cd的增加而降低,采用Logistic模型和完全抑制模型可很好的表征两者之间的关系;通过Logistic模型获得的不同土壤ED25和ED50值分别为2.44~363.03 mg·kg^(-1)、10.99~553.64 mg·kg^(-1),由完全抑制模型拟合结果表明Cd对硝化活性的作用机理为完全抑制作用;基于土壤性质和ED50值建立的多元回归预测模型表明,pH和阳离子交换量(CEC)共同解释了回归模型变异的95.6%.综上表明在一定范围内土壤硝化活性可表征土壤Cd污染程度,土壤CEC和p H是影响Cd毒性的主控因素,可较好地预测土壤中外源Cd对硝化活性的毒性阈值.Nitrification is one of the most important microbial processes in soil that responds quickly to changes in environment condition,such as heavy metal contamination. This study explored the relationship between soil nitrification activities and Cd pollution levels,and discussed the main factors affecting the toxicity of Cd. Effects of Cd on nitrification activities in 10 typical soil types in China were studied using laboratory simulation experiments.The results showed that soil nitrification activities decreased in all Cd-contaminated soil except red soil and black soil. Logistic models can describe the dose-response relationship. The ED25 and ED50were 2.44 ～ 363.03 mg·kg^（-1） and 10.99 ～ 553.64 mg·kg^（-1）,respectively. The main mechanism of Cd on nitrification activity is complete inhibition. The values of ED50 were strongly influenced by p H and CEC contents,which explained up to 95. 6% of the variability. It was therefore indicated that the levels of soil Cd pollution could be characterized by soil nitrification activity to some extent. The developed regression model based on the main soil properties,such as p H,and CEC,can accurately predict Cd toxicity in the soils on nitrification activities.

关 键 词：硝化活性 CD 生态剂量 主控因素 预测模型 

分 类 号：X144[环境科学与工程—环境科学]