改性木屑和稻壳生物炭对土壤镉形态和水稻镉吸收的影响  

Effects of modified sawdust and rice husk biochar on cadmium forms in soil and cadmium uptake by rice

作　　者：曾庆阳 熊振宇 张书扬 林蓉 曾斯远 颜晓[1] 吴建富[1] 魏宗强[1] ZENG Qingyang;XIONG Zhenyu;ZHANG Shuyang;LIN Rong;ZENG Siyuan;YAN Xiao;WU Jianfu;WEI Zongqiang(School of Land Resources and Environment,Jiangxi Agricultural University,Nanchang 330045,China)

机构地区：[1]江西农业大学国土资源与环境学院,江西南昌330045

出　　处：《江西农业大学学报》2024年第4期1066-1075,共10页Acta Agriculturae Universitatis Jiangxiensis

基　　金：国家自然科学基金项目(42267052、32260808)。

摘　　要：【目的】农田镉(Cd)污染对人类健康构成严重威胁,探究不同改性生物炭对我国南方Cd污染农田中Cd形态变化及其在水稻中的富集特征的影响,为南方红壤性水稻土的安全利用和农业发展提供科学依据。【方法】以木屑和稻壳制成木屑生物炭(WCBC)和稻壳生物炭(RHBC),并用KOH和K_(2)SiO_(3)进行改性,共得4种改性生物炭,KOH改性的木屑生物炭(WCBC-KOH)和稻壳生物炭(RHBC-KOH),K_(2)SiO_(3)改性的木屑生物炭(WCBCK_(2)SiO_(3))和稻壳生物炭(RHBC-K_(2)SiO_(3))。通过盆栽试验,研究不同生物炭和添加量(0.25%、0.5%、1%)对红壤性水稻土的影响,包括化学性质(pH和有效硅)、Cd形态、水稻生物量、各组织的Cd富集和硅含量的影响。【结果】6种生物炭均能提高水稻土pH和有效硅含量,且随添加量的增加而增加。添加生物炭减少了土壤中可交换态Cd含量,同时增加了土壤中残渣态Cd含量,导致土壤中Cd的生物有效性和流动性显著降低,进而减少水稻对Cd的吸收。此外,添加生物炭还可以提高水稻地上部干物质重和产量,同时还显著增加了水稻地上部各组织的硅含量。相关分析表明,土壤pH和有效硅含量与可交换态Cd和水稻各组织Cd含量极显著负相关,且土壤pH降镉作用大于土壤有效硅的作用。【结论】6种生物炭均可使土壤中Cd向植物难利用形态转化,同时促进水稻生长和提高水稻产量,添加KOH和K_(2)SiO_(3)改性生物炭的效果要优于未改性生物炭。[Objective]The contamination of farmland by cadmium(Cd)poses a serious threat to human health.This study aims to assess the effects of different modified biochars on the morphological changes of Cd in Cd-contaminated farmland in southern China and its enrichment characteristics in rice,thus providing a scientific foundation for the safe utilization of such soils.[Method]Wood chips and rice husks were used to produce wood chip biochar(WCBC)and rice husk biochar(RHBC).With the modification by KOH and K_(2)SiO_(3),four biochars were obtained,namely KOH-modified wood chip biochar(WCBC-KOH),rice husk biochar(RHBC-KOH),K_(2)SiO_(3)-modified wood chip biochar(WCBC-K_(2)SiO_(3))and rice husk biochar(RHBC-K_(2)SiO_(3)).A pot experiment was conducted to investigated the effects of different biochars and addition rates(0.25%,0.5%,1%),including soil chemical properties(pH and available silicon),Cd forms,rice biomass,and Cd accumulation and silicon contents in various rice tissues[.Result]All six types of biochar increased the pH and available silicon content of paddy soil,with higher addition rates resulting in higher increase.The addition of biochar reduced the exchangeable Cd content in the soil,while increasing the residual Cd content.This resulted in a significant reduction in the bioavailability and mobility of Cd in the soil,subsequently decreasing the uptake of Cd by rice.Additionally,the addition of biochar enhanced the aboveground biomass and yield of rice,while significantly increasing the silicon content in various rice tissues.Correlation analysis indicates a highly significant negative correlation between soil pH and available silicon content with exchangeable Cd and Cd content in rice tissues.Soil pH had a greater effect on Cd reduction than that of available silicon in the soil.[Conclusion]All six types of biochar are effective in transforming Cd in the soil into less available forms for plants,while promoting rice growth and increasing rice yield.The effect of biochars modified with KOH and K_(2)SiO_(3)is bet

关 键 词：改性生物炭 硅 土壤镉形态 镉积累 水稻 

分 类 号：X71[环境科学与工程—环境工程] X53[农业科学—作物学] S511