不同氮肥策略对汞污染土壤修复效果的影响  

Influence of Nitrogen Fertilization Strategies on Effects of Hg-Contaminated Soil Remediation

作　　者：曹昊宇 杨波 郑向群 柳博 王强 CAO Haoyu;YANG Bo;ZHENG Xiangqun;LIU Bo;WANG Qiang(Agro-environmental Protection Institute,Ministry of Agriculture and Rural Affairs,Tianjin 300191,China)

机构地区：[1]农业农村部环境保护科研监测所,天津300191

出　　处：《环境科学与技术》2022年第1期28-38,共11页Environmental Science & Technology

基　　金：天津市自然科学基金(19JCQNJC13400);国家重点研发计划(2016YFD0800406)。

摘　　要：为明确不同施氮肥策略对汞污染土壤的改良效果及其对土壤细菌群落的影响作用,该研究选取受汞污染的酸性土壤(G)和碱性土壤(S)为研究对象,分别设置未施肥空白对照(GK、SK)、仅施速效氮肥(GA、SA)、仅施缓释氮肥(GS、SS)以及生物炭配施缓释氮肥(GB、SB)8种实验处理,基于盆栽实验,探究各处理对汞污染土壤的改良作用、微生物群落的影响,并进一步明确对作物安全的作用效果。结果表明,与GK、SK相比,施肥使汞污染土壤中汞含量分别降低了20.47%~81.60%(酸性)与23.38%~75.74%(碱性);与GA、SA相比,GS、SS处理中,土壤中汞含量分别显著降低了75.96%、69.86%;值得注意的是,生物炭配施处理(GB、SB)对汞污染土壤的改良效果与仅缓释氮肥(GS、SS)处理之间并无显著差异。生物炭配施缓释氮肥处理与其他各处理相比,对原土壤微生物群落结构影响显著,其中,酸性土壤的微生物丰度增加了6.23%,多样性下降11.36%,而碱性土壤中二者均呈下降趋势,分别下降了17.69%、16.81%。对韭菜中汞含量的研究发现,各施氮肥处理中,酸性土壤的可食用部分与根部的汞含量分别下降20.38%~66.46%、20.76%~35.22%;而在碱性土壤中,仅配施处理中作物的可食用部分与根部中的汞含量显著下降,与仅缓释氮肥相比显著下降,分别为45.05%、28.15%。根据Spearman相关性分析金属汞、pH和有机质是影响细菌群落的重要因子。由此可得,施缓释氮肥是降低汞污染土壤的最佳策略,而生物炭配施缓释氮肥在有效改良土壤汞污染(尤其酸性土壤)的同时,显著提高了土壤中细菌的丰度,降低作物中汞含量。该研究在为汞污染土壤改良提供理论依据的同时,探究了缓释氮肥及其与生物炭配施的作用效果。To probe into the effects of nitrogen(N)fertilizer application strategies on the effects of mercury(Hg)-contaminated soil remediation aiming at clear-cut crop-safe measures,pot experiments were conducted to determine soil properties,microbial communities,and eight experimental treatments were carried out including four kinds of N application strategies respectively in acid and alkaline soils:(1)GK,SK(blank control group);(2)GA,SA(applying readily available N-fertilizer);(3)GS,SS(applying slow-release N-fertilizer);and 4)GB,SB(applying slow-release N-fertilizer plus biochar).The experimental results showed that in contrast with the control group(GK,SK),N fertilization could reduce Hg content in acid soil by20.47%to 81.60%and 23.38%to 75.74%in alkaline soil;comparing with group GA,SA,GS,SS showed reduction of soil Hg content by 75.96%and 69.86%(in acid soil and alkaline soil),respectively.It was worthwhile to note that the treatment using biochar(GB,SB)had no notable effects on the remediation of Hg contaminated soil,compared with the treatment using slowrelease N fertilizer(GS,SS).In contrast with other treatments,slow-release N fertilizer with biochar considerably impacted the soil microbial community structure,i.e.the microbial abundance of acidic soil increased by 6.23%and the diversity decreased by 11.36%,while these two groups in alkaline soil both showed a downward trend,with a decrease of 17.69%and16.81%respectively.In regard to the investigation on Hg in leaks,in contrast with the control group,all the N-fertilizer application groups showed that Hg content in leeks edible parts and roots decreased by 20.38%to 66.46%and 20.76%to 35.22%in acid soil,respectively.However,in alkaline soil only slow-release N fertilizer plus biochar group(GB,SB)could remarkably reduced Hg content in edible parts and roots,and compared with group slow-release N fertilizer(GS,SS),declined by 45.05%and 28.15%,respectively.Moreover,according to Spearman correlation analysis,soil pH,organic matter and Hg content were the critical fac

关 键 词：土壤 汞污染 缓释氮肥 生物炭 微生物群落 

分 类 号：X53[环境科学与工程—环境工程] S143.1[农业科学—肥料学]