腐殖质活性组分对土壤镉有效性的调控效应与水稻安全临界阈值  

Regulation Effects of Humus Active Components on Soil Cadmium Availability and Critical Threshold for Rice Safety

作　　者：胡秀芝 宋毅 王天雨 蒋珍茂[1,2] 魏世强[1,2] HU Xiu-zhi;SONG Yi;WANG Tian-yu;JIANG Zhen-mao;WEI Shi-qiang(College of Resources and Environment,Southwest University,Chongqing 400715,China;Chongqing Key Laboratory of Agricultural Resources and Environment Research,Chongqing 400715,China)

机构地区：[1]西南大学资源环境学院,重庆400715 [2]重庆市农业资源与环境研究重点实验室,重庆400715

出　　处：《环境科学》2024年第1期439-449,共11页Environmental Science

基　　金：国家自然科学基金项目(42177012);国家重点研发计划项目(SQ2020YFF0426438);中央高校基本科研业务费专项(SWU120074)。

摘　　要：有机物料对于土壤中镉(Cd)的有效性和作物Cd累积具有重要影响.通过田间小区试验,结合化学连续提取形态分级方法,探讨了有机物料中的主要活性组分胡敏酸(HA)和富里酸(FA)及其不同比例组合(HA/FA)对于水稻吸收累积Cd的影响及其与水稻土中Cd赋存形态和有效性变化的关系.结果表明,腐殖酸(HAs)对土壤Cd有效性和水稻籽粒Cd累积的影响受其活性组分含量比例制约.HA/FA≥4/6处理对土壤Cd起钝化作用,Cd有效性明显降低,水稻籽粒Cd含量相较于对照CK降低了15.2%~33.3%.HA/FA≤2/8处理对土壤Cd起活化作用,Cd有效性明显增加,水稻籽粒Cd含量相较于CK提高了24.2%~42.4%.HAs活性组分含量比例影响土壤Cd的形态转化,与CK处理相比,HA/FA≥4/6处理使土壤Cd由活性高的EX-Cd向活性低的CA-Cd和FM-Cd转化,而HA/FA≤2/8处理则相反.HAs对土壤pH和有效硫含量的影响随其活性组分的不同而异,水稻分蘖期土壤中pH与HA添加量呈显著正相关,而与FA添加量呈显著负相关,土壤有效硫含量与FA添加量呈显著正相关.因此,为保障水稻品质安全,应选择配比HA/FA≥4/6的有机物料.研究结果为含腐殖酸类有机物料的定向利用提供了科学依据.Organic materials containing humic acids(HAs)play important roles in regulating the bioavailability of cadmium(Cd)in soils and thus its accumulation in crops.The effects of the two active components of HAs,humic acid(HA)and fulvic acid(FA),in organic materials and their different ratios(HA/FA)on Cd uptake and accumulation in rice were investigated using a field plot experiment,and their relationships with the Cd fractions and availability in paddy soil as influenced by the use of these organic materials were analyzed in combination with the fractionation method of chemical continuous extraction.The results showed that the effects of HAs on Cd availability in soil and Cd accumulation in rice grains were controlled by the ratios of the active components in the organic materials.The treatments with an HA/FA ratio≥4/6 had a passivating effect on soil Cd,resulting in a significant reduction in Cd availability.Compared with that in the control without the application of HAs(CK),rice grain Cd concentration was reduced by 15.2%-33.3%,whereas those with an HA/FA ratio≤2/8 activated Cd in soil,and the available Cd content was significantly increased.Compared with that in CK,rice grain Cd concentration was increased by 24.2%-42.4%.The ratios of HA/FA in HAs affected the morphological transformation of soil Cd.Compared with the CK treatment,the treatments with ratios of HA/FA≥4/6 promoted the transformation of soil Cd from the exchangeable form(EX-Cd)with high activity to the carbonate bound form(CA-Cd)and Fe and Mn oxide-bound forms(FM-Cd)with low activity,whereas those with ratios of HA/FA≤2/8 showed the opposite effects.The effects of HA and FA on soil pH and available sulfur concentration differed.Soil pH had a significant positive correlation with HA addition but a negative correlation with FA addition,and soil available sulfur content had a significant positive correlation with FA addition at the rice tillering stage.Therefore,to ensure the quality and safety of rice,organic materials with an HA/FA ratio≥4/6

关 键 词：腐殖酸(HAs) 胡富比(HA/FA) 水稻Cd 有效态Cd Cd赋存形态 临界阈值 

分 类 号：X171.5[环境科学与工程—环境科学]