生物炭+ 石灰混合改良剂对稻田土壤pH、有效镉和糙米镉的影响
Effects of blended amendment(biochar + lime)on pH,available Cd in paddy soiland,Cd content in brown rice
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摘要: 生物炭+ 石灰混合改良剂(BL)由生物炭和石灰以10:1 的重量比配制而成。为了研究该混合改良剂的施用效果,在广东省粤北某矿区附近的Cd 污染稻田进行小区试验。结果表明:与习惯施肥(NPK)对照比较,生物炭+ 石灰处理可以明显提高酸性稻田土壤pH 值0.53 个单位,降低土壤有效态Cd含量24.14%,降低水稻糙米Cd 含量53.12%,以上三者均达到显著水平。土壤pH 值与土壤有效Cd 含量之间、土壤pH 值与糙米Cd 含量之间均呈显著的负相关;土壤有效Cd 含量与糙米Cd 含量之间呈显著的正相关。生物炭+ 石灰处理糙米Cd 含量降低至《GB 2762-2012 食品安全国家标准 食品中污染物限量》中限定Cd 0.2 mg/kg 标准值以下,说明生物炭+ 石灰混合改良剂对治理酸性稻田土壤重金属Cd 污染有显著效果。Abstract: A blended amendment was prepared by mixing biochar and lime(BL) at a mass rate of 10:1. In order to study the effects of application of the BL on remediation of heavy metal Cd contaminated paddy soils,a field experiment was conducted near a mining area in northern Guangdong province. The results showed that the BL increased soil pH by 0.53,decreased soil available Cd by 24.14%,and decreased the Cd content of brown rice by 53.12%(P < 0.05). There were significantly negative linear correlations between the soil pH and the available Cd in soil,and significantly negative linear correlations between the soil pH and the Cd contents in brown rice(P < 0.05). Meanwhile,the available Cd in soil had significantly positive linear correlation with Cd content of brown rice(P < 0.05). The BL treatment could decrease Cd content in brown rice to the limits(0.2 mg/kg) of the National Standard GB 2762-2012. The study indicated that BL was a high-effective material on the remediation of paddy soil contaminated by heavy metal Cd.
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