农业环境科学学报2025，Vol.44Issue(5)：1323-1333,11.DOI:10.11654/jaes.2024-0458
还原性绿脱石氧化驱动施化肥和秸秆还田水稻土溶解性有机质转化机制
Mechanism of dissolved organic matter transformation in paddy soil with the application of fertilizer and straw return driven by oxidation of reduced nontronite
摘要
Abstract
In order to investigate the transformation mechanisms of two types of dissolved organic matter(DOM)under straw return and fertilizer application during the oxidation of Fe(Ⅱ)in iron-containing clay mineral structures.The study used iron-rich reduced nontronite(rNAu-2)as a representative clay mineral and extracted DOM from paddy soils subjected to long-term chemical fertilization(CF)and organic manure with straw returning(HOF)practices(referred to as DOMCF and DOMHoF,respectively).It investigated the effects of DOMcF and DOMHoF on the oxidation of rNAu-2,leading to·OH production,as well as DOM transformation.The study revealed that,DOMHoF undergoes easier mineralization during the oxidation process of rNAu-2[Fe(Ⅱ)=1.2 mmol·L-1].Specifically,after 8 h of oxidation,the cumulative concentration of CO2(calculated by C)formation from DOMHoF(29.6 μg)exceeds that from DOMCF(16.9 μg).Both DOMCF and DOM HoF inhibit the oxidation of rNAu-2 to produce·OH,with DOMHoF exhibiting a more pronounced inhibitory effect.In the absence of DOM,the cumulative amount of·OH produced from the aerobic oxidation of rNAu-2 after 8 hours is 26.06 μmol·L-1,which is higher than that in the rNAu-2/DOMCF(19.83 μmolL-1)and rNAu-2/DOMHor(17.07 μmol·L-1)systems(DOM concentration at 50 mg·L-1).Solid-liquid separation results indicated that the electron transfer between rNAu-2 and DOM or DOM-Fe3+inhibits the structural Fe(Ⅱ)oxidation and·OH production.Three-dimensional excitation-emission matrix spectroscopy(3DEEMs)revealed that straw return promoted the accumulation of humic substances and fulvic acids in paddy soil.After oxidation,significant changes were observed in the humic substances and fulvic acids,whereas their presence was scarcely detected in DOMCF.X-ray photoelectron spectroscopy(XPS)analysis indicates that·OH can add to aromatic structures or olefins through ring-opening and hydroxylation mechanisms,leading to the generation of more oxygen-containing groups(C-O and C＝O).Therefore,the presence of DOM inhibits the oxidation of Fe(Ⅱ)in the rNAu-2 structure and thus inhibits the formation of·OH,while the DOM in the soil where the straw is returned to the field contains more easily decomposed organic matter components,which is more likely to consume·OH and release more CO2.关键词
还原态绿脱石/秸秆还田/羟基自由基(·OH)/DOM转化Key words
reduced chlorite/straw turnover/hydroxyl radicals(·OH)/DOM transformation分类
农业科技引用本文复制引用
符俊宏,肖艳琦,宁雅琪,谢雯静,张娜,崔浩杰,廖文娟..还原性绿脱石氧化驱动施化肥和秸秆还田水稻土溶解性有机质转化机制[J].农业环境科学学报,2025,44(5):1323-1333,11.基金项目
国家自然科学基金项目(42107086,42277291,42307311) （42107086,42277291,42307311）
湖南省教育厅优秀青年基金项目(22B0200) （22B0200）
环境地球化学国家重点实验室项目(SKLEG2024224) （SKLEG2024224）
河北省湿地生态与保护重点实验室项目(hklk202302) （hklk202302）
河北省自然科学基金项目(D2022111001)National Natural Science Foundation of China(42107086,42277291,42307311) （D2022111001）
Scientific Research Fund of Hunan Provincial Education Department(22B0200) （22B0200）
Opening Fund of the State Key Laboratory of Environmental Geochemistry(SKLEG2024224) （SKLEG2024224）
Open Foundation of Hebei Key Laboratory of Wetland Ecology and Conservation(hklk202302) （hklk202302）
Natural Science Foundation of Hebei Province,China(D2022111001) （D2022111001）
