海南典型水稻土厌氧铁还原特征对DOM分子特性的响应  

Response of Iron Reduction Characteristics to DOM Molecular Properties under Anaerobic Conditions in Typical Paddy Soils of Hainan Island

作　　者：黄成 吴月颖 吉恒宽 陈丽铭 李倍莹 符传良 李建宏 吴蔚东[1] 吴治澎[1] HUANG Cheng;WU Yueying;JI Hengkuan;CHEN Liming;LI Beiying;FU Chuanliang;LI Jianhong;WU Weidong;WU Zhipeng(College of Tropical Crops,Hainan University,Haikou 570228,China;College of Ecology and Environment,Hainan University,Haikou,570228,China;Institute of Agricultural Environment and Soil,Hainan Academy of Agricultural Sciences/Hainan Scientific Observation Station of Cultivated Land Conservation of Ministry of Agriculture and Rural Areas/Key Laboratory of Cultivated Land Conservation in Hainan Province,Haikou 571100,China;College of Environmental and Chemical Engineering,Foshan University,Foshan 528011,China)

机构地区：[1]海南大学热带作物学院,海南海口570228 [2]海南大学生态与环境学院,海南海口570228 [3]海南省农业科学院农业环境与土壤研究所/农业农村部海南耕地保育科学观测实验站/海南省耕地保育重点实验室,海南海口571100 [4]佛山科学技术学院环境与化学工程学院,广东佛山528011

出　　处：《生态环境学报》2021年第5期957-967,共11页Ecology and Environmental Sciences

基　　金：海南省基础与应用基础研究计划(自然科学领域)高层次人才基金项目(2019RC022);国家自然科学基金项目(41807326)。

摘　　要：为探究海南典型水稻土不同粒径土壤中溶解态有机质(DOM)的含量组成对铁氧化还原特征的影响机制,分别采集海南5种成土母质发育的水稻土(玄武岩、花岗岩、砂页岩、海相沉积物、河流冲积物),利用紫外-可见光谱技术分析不同粒径土壤中DOM的碳含量及其光谱特征,利用Logistics模型对不同水稻土培养过程中Fe(Ⅲ)还原特征进行表征;采用冗余分析手段分析各水稻土在厌氧培养过程中,不同粒径土壤中DOM组分及光谱参数对Fe(Ⅲ)还原特征影响。结果表明,在厌氧培养过程中,不同母质发育水稻土Fe(Ⅱ)含量不同,其中玄武岩发育水稻土Fe(Ⅱ)含量最大(8.45 mg·g^(−1)),根据Logistics模型发现不同母质发育水稻土的还原潜势(a)和Fe(Ⅲ)还原速率(vmax)存在差异且玄武岩发育水稻土的a、vmax最大。海相沉积物发育水稻土的溶解态有机碳(DOC)含量最高(0.712 g·kg^(−1)),5种水稻土的DOC均在最小粒径(<1 kDa)含量最多,随着培养时间增长各类水稻土中DOC含量均下降,紫外-可见光谱结果显示5种母质发育的水稻土的芳香性和疏水性随着DOC粒径的减小而下降,三维荧光光谱结果表明,不同母质发育水稻土中各组分的荧光强度均随培养时间增长而增强,而在粒径0.45-0.7μm、1-10 kDa中各组分荧光强度增强;在粒径10 kDa-0.45μm、<1 kDa中各组分荧光强度降低;BIX、HIX、FI值均随着粒径的减小而增大。冗余分析结果显示,HIX、SUVA_(260)、C1、C2组分可促进水稻土铁还原过程,不同的培养阶段下铁还原受不同DOM组分的影响,但是C1组分始终影响Fe(Ⅲ)的还原,小粒径的C3、C4组分(<1 kDa)对铁还原有更大贡献。了解海南岛水稻土铁还原对不同分子量DOM的响应,对农业环境具有重要意义。Five types of paddy soils with different parent materials(including basalt, granite, sand shale, marine sediment, and river alluvium) in Hainan Island were collected, aiming to explore the influence mechanisms of the content composition of dissolved organic matter(DOM) on the iron redox characteristics of typical paddy soils. The carbon content and spectral characteristics of DOM in the soils with different parent materials were analyzed using ultraviolet-visible spectroscopy(UV-VIS). The Logistic model was used to characterize the Fe(Ⅲ) reduction characteristics of paddy soils under different incubation processes. The redundancy analysis was used to analyze the effects of DOM components and its spectral parameters on Fe(Ⅲ) reduction characteristics of the paddy soil within different particle sizes under the anaerobic incubation. The results showed that the Fe(Ⅱ) concentrations of paddy soils with different parent materials were different during the anaerobic incubation, while the paddy soil with parent material of basalt having the highest Fe(Ⅱ) concentration(8.45 mg·g-1). According to the logistic model, the reduction potential(a) and the Fe(Ⅲ) reduction rate(vmax) of paddy soils with different parent materials were found to be different and the a and vmax of basaltic paddy soil was the highest. The highest content of dissolved organic carbon(DOC;0.712 g·kg-1) was found in the paddy soil with parent material of marine sediment, and the content of DOC was highest in the smallest particle size(<1 kDa) of all five paddy soils. The content of DOC in all paddy soils decreased with the increasing incubation time. The results of UV-VIS spectroscopy showed that the aromaticity and hydrophobicity of paddy soils with five parent materials decreased with decreasing DOC particle size. The results of three-dimensional fluorescence spectrum showed that the fluorescence intensity of each DOM component in paddy soil with different parent materials increased with the increasing of incubation time, while the fluoresc

关 键 词：水稻土 溶解态有机质 粒径分布 铁(Ⅲ)还原 冗余分析 Logistics模型 

分 类 号：S153[农业科学—土壤学] X144[农业科学—农业基础科学]