磁铁矿对稻田土壤碳矿化的影响  

Effects of Fe_(3)O_(4) on Soil Carbon Mineralization in Paddy Field

作　　者：梁鑫 韩亚峰 郑柯 王旭刚[1,3] 陈志怀 杜鹃 LIANG Xin;HAN Yafeng;ZHENG Ke;WANG Xugang;CHEN Zhihuai;DU Juan(Agricultural College,Henan University of Science and Technology,Luoyang 471000,P.R.China;Luoyang Key Laboratory of Plant Nutrition and Environmental Ecology,Luoyang 471000,P.R.China;Luoyang Key Laboratory of Symbiotic Microbes and Green Development,Luoyang,Henan 471000,P.R.China;Luoyang Agricultural Technology Extension Service Center,Luoyang 471003,P.R.China)

机构地区：[1]河南科技大学农学院,河南洛阳471000 [2]洛阳市植物营养与环境生态重点实验室,河南洛阳471000 [3]洛阳市共生微生物与绿色发展重点实验室,河南洛阳471000 [4]洛阳市农业技术推广服务中心,河南洛阳471003

出　　处：《生态环境学报》2023年第9期1615-1622,共8页Ecology and Environmental Sciences

基　　金：国家自然科学基金项目(41601309,U1904121)。

摘　　要：厌氧条件下土壤铁还原与碳循环紧密相关,然而针对稻田土壤中异化铁还原与碳矿化关系的认识尚有不足。采用黄河中下游地区河南孟津稻田土壤为研究对象,分别将50.0、100、200、400 mg磁铁矿(Fe_(3)O_(4))粉末添加至3.00 g稻田土壤,设置恒温厌氧泥浆培养实验,期间动态监测土壤0.5 mol·L^(−1)HCl可提取态Fe(Ⅱ)、水溶性有机碳(WSOC)、水溶性无机碳(WSIC)、铁氧化物形态、CO_(2)和CH4排放的变化。结果表明,外源添加Fe_(3)O_(4)可显著提高土壤铁还原潜势,增幅为0.883-4.53 mg·kg^(−1),但对最大铁还原速率和铁还原速率常数无显著影响;添加Fe_(3)O_(4)显著提高了WSIC含量,增加值达88.4 mg·kg^(−1),降低了WSOC含量,降低值为62.7 mg·kg^(−1),减弱微生物对土壤有机碳分解作用及CO_(2)的外排风险;提高Fe_(3)O_(4)添加量对CO_(2)累积排放量无显著影响,但显著抑制了土壤CH4的累积排放量,降低值介于11.1-76.3 mg·kg^(−1),降幅最高达56.3%,表明外源添加Fe_(3)O_(4)降低了土壤碳矿化风险;培养结束后矿化产物CO_(2)与CH4累积排放量占比呈现显著增长趋势,最高值可达174%,表明培养周期内CH4排放随外源Fe_(3)O_(4)添加量增加而被显著抑制,液相矿化产物分配占比则随外源Fe_(3)O_(4)添加量增加显著增加,增幅最大达15%,表明厌氧培养中外源Fe_(3)O_(4)添加可显著抑制温室气体排放。相关分析显示,土壤Fe还原潜势、游离态铁氧化物(Fed)与CH4累积排放量和CH4排放速率均呈现出极显著负相关关系,表明外源添加Fe_(3)O_(4)增强的异化铁还原显著抑制了土壤有机碳的矿化。研究结果对进一步理解水稻土壤异化铁还原及其耦合的碳转化机理具有重要意义。Soil iron reduction under anaerobic conditions is closely related to carbon cycle,however,the relationship between dissimilar iron reduction and carbon mineralization in paddy soil is still insufficiently understood.In this experiment,the paddy soil in Mengjin,Henan Province in the middle and lower reaches of the Yellow River was selected as the study object,and the soil was divided into 50.0,100,200,and 400 mg,respectively.Magnetite(Fe_(3)O_(4))powder was added to 3.00 g paddy soil,and constant temperature anaerobic mud culture experiment was set up.During the culture experiment,the changes of CO_(2)and CH4 emissions in the extractable Fe(Ⅱ),water-soluble organic carbon(WSOC),water-soluble inorganic carbon(WSIC),and the form of iron oxide in the soil were dynamically monitored.The results showed that exogenous addition of Fe_(3)O_(4)could significantly increase the soil iron reduction potential by 0.88–4.53 mg·kg^(−1),but had no significant effect on the maximum iron reduction rate and iron reduction rate constant.The addition of Fe_(3)O_(4)significantly increased the content of WSIC(88.4 mg·kg^(−1)),decreased the content of WSOC(62.7 mg·kg^(−1)),and weakened the decomposition of soil organic carbon by microorganisms and the risk of CO_(2)expulsion.Increasing Fe_(3)O_(4)supplemental level had no significant effect on the cumulative CO_(2)emissions,but significantly inhibited the cumulative soil CH4 emissions,with a decreasing value between 11.1–76.3 mg·kg^(−1)and a maximum decrease of 56.3%,indicating that exogenous Fe_(3)O_(4)supplementation reduced the risk of soil carbon mineralization.After the end of the culture,the cumulative emissions of CO_(2)and CH4 of the mineralized products showed a significant increasing trend,and the highest value reached 174%,indicating that CH4 emission was significantly inhibited with the increase of exogenous Fe_(3)O_(4)addition during the culture cycle,while the distribution of liquid phase mineralized products was significantly increased with the increase of

关 键 词：稻田土壤 异化铁还原 Fe_(3)O_(4) 土壤碳矿化 温室气体 土壤有机碳 

分 类 号：S153[农业科学—土壤学] X16[农业科学—农业基础科学] X154.2[环境科学与工程—环境科学]