玉米秸秆炭对红壤镉吸附及养分含量、赋存形态的影响

汪宜敏; 唐豆豆; 张晓辉; 袁旭音; 徐兰

文章摘要

汪宜敏,唐豆豆,张晓辉,袁旭音,徐兰.玉米秸秆炭对红壤镉吸附及养分含量、赋存形态的影响[J].农业环境科学学报,2017,36(12):2445-2452.

玉米秸秆炭对红壤镉吸附及养分含量、赋存形态的影响

Effects of corn-straw biochar on cadmium adsorption, nutrient contents, and chemical forms in red soil

投稿时间：2017-07-08

DOI：10.11654/jaes.2017-0964

中文关键词: 红壤玉米秸秆炭镉养分元素等温吸附

英文关键词: red soil corn-straw biochar cadmium nutrient elements isothermal adsorption

基金项目:中央高校基本科研业务费专项资金（2015B12314）；江苏省自然科学基金（BK20160859）；国家自然科学基金（41601540）；国家重点研发计划专项（2017YFD0800302）

作者	单位	E-mail
汪宜敏	河海大学环境学院, 南京 210098
唐豆豆	河海大学环境学院, 南京 210098
张晓辉	河海大学环境学院, 南京 210098
袁旭音	河海大学环境学院, 南京 210098	yxy_hjy@hhu.edu.cn
徐兰	河海大学环境学院, 南京 210098

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中文摘要:

为明确玉米秸秆炭添加对土壤重金属镉（Cd）的吸附固持及主要养分元素N、P形态转化的影响，以土壤质量0%、2%、4%和8%的比例向红壤中加入玉米秸秆生物质炭材料，混合后培养35 d，通过等温吸附实验探究玉米秸秆炭施加对红壤中Cd²⁺吸附的影响及其作用机制，并结合逐级化学提取法对红壤养分元素N、P和K的生物可利用性及其赋存形态变化进行研究。结果表明，玉米秸秆炭的施加能增加红壤pH值和有机碳总量，并显著提高红壤上Cd²⁺的吸附量，Freundlich和Langmuir方程均能够较好拟合该等温吸附过程（R²>0.90）；SEM-EDAX分析表明生物质炭吸附了部分土壤中的Cd²⁺，在pH 4~8范围内，土壤pH值的增大促进了红壤对Cd²⁺的吸附；土壤悬液Zeta电位结果表明玉米秸秆炭的施加增加了土壤表面的负电荷量，使得红壤通过静电吸附作用结合更多的Cd²⁺。此外，生物质炭的施加提高了土壤中离子交换态磷（KCl-P）、离子交换态氮（IEF-N）和速效钾含量，土壤中不同形态磷（Ca-P、Fe-P）含量随着生物质炭的增加均呈现上升趋势，而土壤中总可转化态氮（TTN）的含量则变化不明显。以上结果表明，玉米秸秆炭的施用能有效降低重金属污染土壤的环境风险，提高土壤质量。

英文摘要:

To better understand the effects of corn-straw biochar on soil cadmium (Cd) adsorption, and chemical forms of nitrogen (N) and phosphorus (P) and their transformation in soil, we performed an incubation experiment with the addition of different biochar levels. Red soil samples were mixed with corn-straw biochar, at a ratio of 0%, 2%, 4%, and 8% soil weight. These mixtures were cultivated in an incubator for 35 days. We explored the effects and mechanisms of biochar addition on soil Cd²⁺ adsorption, and the bioavailability and chemical forms of nutrient elements[N, P, and potassium (K)] in red soil using isothermal adsorption and chemical extraction methods. Results showed that biochar addition increased the soil pH and organic matter content, and enhanced the Cd²⁺ adsorption capacities in soil. These adsorption behaviors were well fitted with both Freundlich and Langmuir equations (R²>0.90). The results of SEM-EDAX indicated that the biochar had adsorbed some Cd²⁺ in the studied soil. Owing to soil pH changes by biochar addition, we explored the role of different pH values on red soil Cd²⁺ adsorption behavior. At pH 4~8, Cd²⁺ adsorption by red soil was enhanced with increasing pH. Zeta potential results of soil suspension showed that biochar application could increase the amount of negative charge in soil, thus proving that more Cd²⁺ would be adsorbed in red soil through the electrostatic effect. In addition, the chemical forms of the nutrient elements varied in response to biochar application in red soil. Specifically, the bioavailable forms of P (KCl-P), N (IEF-N), and K in red soil significantly increased with biochar addition. The P forms (Ca-P, Fe-P) were also enhanced by biochar addition, but no significant changes in total transferable N (TTN) content was observed. Based on the above results, we concluded that corn-straw biochar application could decrease the environmental risk of heavy metal contaminated soil, and significantly improve the quality of soil fertility.

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