改性凹凸棒土复配秸秆生物炭对生菜镉吸收的影响及机理  

Effect and mechanism of modified attapulgite combined with straw biochar on cadmium absorption of lettuce

作　　者：钟振宇[1] 姜苹红[1] 崔啸川 谢可军 ZHONG Zhen-yu;JIANG Ping-hong;CUI Xiao-chuan;XIE Ke-jun(Hunan Research Academy of Environmental Sciences,Changsha,Hunan 410018,China;College of Environment and Ecology,Hunan Agricultural University,Changsha,Hunan 410128,China;Hunan Provincial Center of Ecology and Environment Affairs,Changsha,Hunan 410019,China)

机构地区：[1]湖南省环境保护科学研究院,湖南长沙410018 [2]湖南农业大学环境与生态学院,湖南长沙410128 [3]湖南省生态环境事务中心,湖南长沙410019

出　　处：《农业现代化研究》2024年第4期702-710,共9页Research of Agricultural Modernization

基　　金：国家自然科学基金项目(U21A2033)。

摘　　要：土壤镉(Cd)污染加剧,单一施用天然材料降Cd效率较低,材料改性与复配是实现土壤Cd高效修复的重要途径。为此,本研究采用生菜盆栽试验,探讨了改性凹凸棒土单施及其复配秸秆生物炭施用对土壤理化性质、土壤Cd活性和赋存形态以及生菜生长发育和Cd吸收等的影响。结果表明,改性凹凸棒土单施显著降低了土壤Cd活性47.50%~67.19%、生菜Cd含量31.82%~36.36%,增加了生菜地上部干重8.45%~11.27%(P<0.05)。凹凸棒土复配秸秆生物炭显著降低了土壤Cd活性40.00%~72.50%,提高了土壤pH 0.21~0.36个单位、有机质含量13.10%~15.53%、电导率37.42%~50.10%和阳离子交换量7.97%~12.75%(P<0.05);显著降低了生菜Cd含量28.79%~39.90%,同步增加了生菜地上部干重13.15%~21.13%(P<0.05),其中铁改性凹凸棒土复配秸秆生物炭效果最佳。铁改性凹凸棒土复配秸秆生物炭促进了Cd由活性态向稳定态转化。路径分析显示,土壤pH是直接影响土壤Cd活性的首要影响因子,土壤Cd活性直接影响生菜Cd含量。因此,铁改性凹凸棒土复配秸秆生物炭可显著提高土壤pH和改善土壤结构,促进土壤Cd稳定化和生菜生长,进而降低土壤Cd活性,进一步抑制生菜Cd吸收,具备较强土壤Cd污染修复应用潜力。The intensification of cadmium(Cd)contamination in soil and the low efficiency of Cd reduction by sole application of natural materials have made material modification and compounding important approaches to achieving efficient remediation of Cd-contaminated soil.To this end,a pot experiment with lettuce was conducted to investigate the effects of the sole application of modified attapulgite and its combined application with straw biochar on soil physicochemical properties,soil Cd availability and speciation,as well as lettuce growth,development,and Cd absorption.The results indicated that the calcined and iron-modified attapulgite significantly reduced soil Cd availability by 47.50%~67.19%,the Cd content in lettuce by 31.82%-36.36%,and increased the lettuce dry weight by 8.45%~11.27%(P<0.05).The attapulgite combined with straw biochar significantly decreased soil Cd availability by 40.00%~72.50%,increased soil pH by 0.21~0.36 units,organic matter content(OM)by 13.10%-15.53%,electrical conductivity(EC)by 37.42%~50.10%,and cation exchange capacity(CEC)by 7.97%~12.75%(P<0.05),reduced the Cd content of lettuce by 28.79%~39.90%,and enhanced the dry weight of lettuce by 13.15%~21.13%(P<0.05).The best effect was obtained by the iron-modified attapulgite combined with straw biochar.This combination promoted the transformation of Cd from an active state to a stable state.The SEM analysis revealed that soil pH was the primary determinant directly influencing soil Cd availability,which in turn had a direct impact on Cd content in lettuce.Therefore,the combination of iron-modified attapulgite with straw biochar could significantly enhance soil pH,improve soil structure(by increasing OM,CEC,etc.),synergistically promote soil Cd stabilization and lettuce growth,and reduce soil Cd availability and Cd absorption in lettuce,demonstrating strong application potential for soil Cd pollution remediation.

关 键 词：改性凹凸棒土 生物炭 Cd活性 土壤修复 生菜Cd 

分 类 号：X53[环境科学与工程—环境工程]