钾对土壤镉有效性的影响及其机理  

Effect of Potassium Cations on Cadmium Bioavailability and Its Mechanisms in Lateritic Red Soils

作　　者：宋正国[1,2] 徐明岗[2] 丁永祯[1] 孙楠[2] 刘平[2] 唐世荣[1] 

机构地区：[1]农业部环境保护科研监测所农业部产地环境与农产品安全重点开放实验室,天津300191 [2]中国农业科学院农业资源与农业区划研究所,北京100081

出　　处：《中国矿业大学学报》2010年第3期453-458,共6页Journal of China University of Mining & Technology

基　　金：国家重点基础研究发展计划(973)项目(2002CB410809);北京市自然科学基金项目(6062026)

摘　　要：分析了不同用量钾肥对土壤镉有效性的影响,采用盆栽与等温吸附试验,研究了镉污染赤红壤上,施用钾肥对小油菜生物量、镉吸收量与土壤溶液中钾、镉含量及土壤镉吸附等的影响.结果表明:无论是低镉还是高镉污染水平,与对照相比,小油菜干质量均以高钾用量增幅最大,两季平均增加分别为16.6%(低镉)和17.7%(高镉).在低、高镉两种污染水平下,增加钾肥的施用量,土壤溶液中钾含量明显增加,小油菜体内钾含量也明显增加.钾肥施用量为195 mg/kg时,土壤溶液中镉含量最高,较对照分别增加2.80%(低镉)与23.7%(高镉);而小油菜体内镉含量较对照平均分别增加10%(低镉)和45.9%(高镉).钾离子与镉共存时,明显改变土壤吸附镉的能力,与钠体系相比,钾体系赤红壤的总吸附容量降低了31.3%.钾与镉共存时,土壤对镉的吸附作用明显影响小油菜对镉的吸收,是控制土壤镉有效性的关键因子.Based on the importance of co-existingcations in soils that may change bioavailability of cadmium, the effect of applied different rates of K fertilizers on bioavailability of cadmium was investigated. Pot and isothermal adsorption experiments were explored to investigate the effect of the K fertilizers applied onto Cd-contaminated lateritic red soil on rape biomass, Cd accumulation, K and Cd concentrations in soil solution as well as adsorption of cadmium. The results show that, compared with the control, the rape dry mass increased to a great extent when grown on soils spiked with either low or high concentrations of K regardless of Cd levels, with the average increases of dry mass for two seasons being 16.6% for low level of Cd and 17.7% for high level of Cd. At either low or high levels of Cd, with the increase of K application, K concentration in soil solution increased, and K concentration in rape organs increased as well. At 195 mg/kg of K applied to the soil, the Cd concentration in soil solution reached up to themaximum, being by 2.80% and 23.7% for low and high levels of Cd, respectively, compared with the control, but Cd concentration in rape organs increased on average by 10% and 45.9%, respectively. Coexistence of K and Cd cations in soils may change the adsorption ability of Cd significantly. The total adsorption amount of Cd in K system decreased by 31.3% compared with the Na applied system. When potassium co-existed with cadmium, soil adsorption on Cd significantly affects Cd uptake by rape, and could be a key controlling factor that influences cadmium bioavailability.

关 键 词：镉 钾 小油菜 赤红壤 有效性 

分 类 号：X503.231[环境科学与工程—环境工程]