不同类型氮输入对三峡库区消落带紫色潮土氮赋存形态的影响  

Effects of Different Types of Nitrogen Inputs on Purple Alluvial Soil Nitrogen Fractions in Riparian Zone of Three Gorges Reservoir Area

作　　者：何立平[1,2] 林俊杰 段林艳[1] 陆伟 HE Liping;LIN Junjie;DUAN Linyan;LU Wei(Key Laboratory of Water Environment Evolution and Pollution Control in Three Gorges Reservoir,Chongqing Three Gorges University,Chongqing 404100,China;Collaborative Innovation Center of Ecological Environment Protection and Disaster Prevention in the Three Gorges Reservoir Area,Chongqing Three Gorges University,Chongqing 404100,China)

机构地区：[1]重庆三峡学院,三峡库区水环境演变与污染防治重庆高校市级重点实验室,重庆404100 [2]三峡库区生态和灾害防治重庆市协同创新中心,重庆404100

出　　处：《环境科学研究》2021年第9期2228-2236,共9页Research of Environmental Sciences

基　　金：重庆市教委科学技术研究项目(No.KJQN201801233);三峡库区可持续发展研究中心开放基金项目(No.18sxxyjd11);三峡库区水环境演变与污染防治重庆高校市级重点实验室开放基金项目(No.WEPKL2019YB-05)

摘　　要：陆源氮输入是三峡水体富营养化的主要原因之一,外源氮在消落带土壤中的赋存形态是决定其进一步向三峡水体释放的关键.为此,以三峡典型土壤-紫色潮土为研究对象,进行4种氮输入〔分别添加NaNO_(3)、NH_(4)NO_(3)、(NH_(4))_(2)SO_(4)、CO(NH_(2))_(2)〕和淹水-落干两个水文条件处理,利用连续分级提取法测定土壤氮赋存形态含量,分析氮添加类型及水文条件对消落带紫色潮土氮赋存形态的影响.结果表明:NaNO_(3)、NH_(4)NO_(3)、(NH_(4))_(2)SO_(4)和CO(NH_(2))_(2)添加下,土壤培养结束后,离子交换态氮(IEF-N)含量在落干期分别为93.88、79.42、59.02和46.80 mg kg,在淹水期分别为65.60、56.95、42.46和32.94 mg kg;有机及硫化物结合态氮(OSF-N)含量在落干期分别为122.18、126.21、137.53和148.19 mg kg,在淹水期分别为142.22、149.09、156.43和161.76 mg kg;IEF-N含量变化占比在落干期分别为45.20%、35.56%、21.96%和13.82%,在淹水期分别为36.57%、30.80%、16.21%和7.26%;OSF-N含量变化占比在落干期分别为12.33%、15.02%、22.57%和29.68%,在淹水期分别为16.76%、21.84%、26.73%和30.29%.落干期和淹水期,IEF-N含量及其变化在氮添加总量中的占比均表现为NaNO_(3)添加下最高、CO(NH_(2))_(2)添加下最低,且落干期大于淹水期;OSF-N含量及其变化占比则与IEF-N表现相反.落干期和淹水期,外源氮主要表现为向OSF-N转化,此外,外源氮在落干期还存在向铁锰氧化物结合态氮转化的过程.研究显示,控制落干期消落带土壤氮输入(特别是硝态氮)是预防三峡水库富营养化的有效途径.Terrestrial nitrogen(N)input is one of the main reasons for the eutrophication in the Three Gorges Reservoir(TGR).The chemical form of exogenous N in the riparian zone soil plays a crucial role in its further release into the TGR.Purple alluvial soils were collected in the riparian zone of the TGR,and soil N fractions were measured using the sequential fractionation method.Soil N fractions were investigated under the treatments of four types of N input(NaNO_(3),NH_(4)NO_(3),(NH_(4))_(2)SO_(4),CO(NH_(2))_(2))and two hydrological conditions(dry and flood).The results showed that with the addition of NaNO_(3),NH_(4)NO_(3),(NH_(4))_(2)SO_(4) and CO(NH_(2))_(2),the contents of soil ion-exchangeable form(IEF-N)were 93.88,79.42,59.02 and_(4)6.80 mg kg after the dry incubation,respectively,and were 65.60,56.95,42.46 and 32.94 mg kg after the flood incubation,respectively;the contents of soil organic matter-sulfide form(OSF-N)were 122.18,126.21,137.53 and 148.19 mg kg after the dry incubation,respectively,and were 142.22,149.09,156.43 and 161.76 mg kg after the flood incubation,respectively.Meanwhile,with the addition of NaNO_(3),NH_(4)NO_(3),(NH_(4))_(2)SO_(4) and CO(NH_(2))_(2),the proportions of the content of IEF-N change in the amount of total N addition were_(4)5.20%,35.56%,21.96%and 13.82%after the dry incubation,respectively,and were 36.57%,30.80%,16.21%and 7.26%after the flood incubation,respectively;the proportions of the content of OSF-N change in the amount of total N addition were 12.33%,15.02%,22.57%and 29.68%after the dry incubation,respectively,and were 16.76%,21.84%,26.73%and 30.29%after the flood incubation,respectively.The content of IEF-N and the proportion of its change in the amount of total N addition were the highest with NaNO_(3) addition,and the lowest with CO(NH_(2))_(2) addition during both the dry and flood periods.Moreover,they were much higher in the dry period than that in the flood period.However,the opposite results were observed for that of OSF-N.We concluded that the exogenous N was mos

关 键 词：氮形态变化速率 氮形态变化占比 氮类型 落干期 淹水期 

分 类 号：X142[环境科学与工程—环境科学]