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1、2013,32(9):1786—1792農(nóng)環(huán)境科學(xué)學(xué)報(bào)2013年9月Journalagro-EnvironmentScience鎘污染稻草還田對土壤鎘形態(tài)轉(zhuǎn)化的影響曹曉玲,一,羅尊長,黃道友,朱奇宏,劉守龍,饒中秀,任雪菲,席園1(1沖國科學(xué)院亞熱帶農(nóng)業(yè)生態(tài)研究所,亞熱帶農(nóng)業(yè)生態(tài)過程重點(diǎn)實(shí)驗(yàn)室,長沙410125;2.湖南省土壤肥料研究所,長沙410125)摘要:采用模擬培養(yǎng)實(shí)驗(yàn),研究了鎘污染稻草還田后清潔土壤(pH=4.72)和鎘污染土壤(pH=7.90)中有效態(tài)鎘含量及鎘形態(tài)分布的變化特征。結(jié)果表明:添加稻草和淹水培養(yǎng)使土壤pH值向6.0—7.5的區(qū)間轉(zhuǎn)變,并
2、顯著提高了土壤可溶性有機(jī)碳(DOC)含量。清潔土壤添加鎘污染稻草后,土壤DTPA(Diethylenetriaminepentacetateacid)提取態(tài)cd含量增加23.5%一225.0%,土壤酸提取態(tài)和可還原態(tài)鎘的相對比例顯著提高,而殘?jiān)鼞B(tài)和可氧化態(tài)鎘的比例則相對降低,其效果隨稻草添加量的增加顯著增強(qiáng);鎘污染土壤添加鎘污染稻草后,DTPA提取態(tài)鎘僅在培養(yǎng)初期(2d)略有提高,隨培養(yǎng)時(shí)間的延長,DTPA提取態(tài)鎘含量顯著降低(28.6%~41.1%),且添加稻草促使酸提取態(tài)鎘向可還原態(tài)鎘和殘?jiān)鼞B(tài)鎘轉(zhuǎn)化。研究表明,鎘污染稻草進(jìn)入清潔土壤會帶來鎘污染的擴(kuò)散風(fēng)險(xiǎn),而
3、進(jìn)入供試污染土壤后則能在一定程度上降低污染土壤中鎘的有效性。關(guān)鍵詞:稻草還田;Cd污染;清潔土壤;污染土壤;土壤Cd形態(tài)中圖分類號:X53文獻(xiàn)標(biāo)志碼:A文章編號:1672—2043(2013)09—1786—07doi:10.116546aes.2013.09.012EfectsofCd-contaminatedRiceStrawInc0rp0rati0nonTransformationofCdFormsinSoilsCAOXiao-ling。,LUOZun-chang,HUANGDao-you’,ZHUQi-hong,LIUShou-long,RAOZhong
4、-xiu,RENXue-~i,XIYuan(1.KeyLaboratoryforAgro—ecologicalProcessesinSubtropicalRegion,InstituteofSubtropicalAgricuhure,CAS,Hunan410125,China;2.HunanSoilandFertilizerInstitute,Hunan410125,China).Abstract:ToinvestigatetheeffectsofCd—contaminatedricestrawincorporationontheCdfractionsandth
5、eavailableCdcontentsinsoils(anon-contaminatedsoil,pH=4.72andaCd—contaminatedsoil,pH=7.90)anincubationexperiment(28d)wasconducted.Theresultsindi—catedthataftertheadditionofricestraw(bothcontaminatedandcleanricestmw)thepHinbothsoilswereneutralized(6.0to7.5)andthecontentsofdissolvedorga
6、niccarbon(DOC)inbothsoilsweresharplyincreasedinthefirst2dandreducedgraduallyintherestincubationperiod.Atthesametime.Cd—contaminatedricestrawincorporationsignificantlyincreasedtheDTPAextractableCdbv23.5%~225.0%andtheproportionsofacid-extractableandreducibleCd,andrelativelydecreasedthe
7、proportionsofresidualandoxidizableCdincleansoil.TheseeffectswereenhancedwiththeincreasingofCd-contaminatedricestrawadded.ereas.inCd—contaminatedsoil.theDTPAex—tractableCdwasslightlyincreasedfirstly。andthendecreased(by28.6%~41.1%)continuallyduringtherestincubationperiod(2-28d)whenCd—c
8、ontaminatedr