| 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. |
| 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 |
| 投稿时间：2024-06-01 |
| DOI：10.11654/jaes.2024-0458 |
| 中文关键词: 还原态绿脱石 秸秆还田 羟基自由基（·OH） DOM转化 |
| 英文关键词: reduced chlorite straw turnover hydroxyl radicals（·OH） DOM transformation |
| 基金项目:国家自然科学基金项目（42107086，42277291，42307311）；湖南省教育厅优秀青年基金项目（22B0200）；环境地球化学国家重点实验室项目（SKLEG2024224）；河北省湿地生态与保护重点实验室项目（hklk202302）；河北省自然科学基金项目（D2022111001） |
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| 中文摘要: |
| 为探讨秸秆还田和化肥施用下的两种溶解性有机质（DOM）在含铁黏土矿物结构态Fe（Ⅱ）氧化过程中的转化机制，本文以富铁的还原态绿脱石（rNAu-2）为黏土矿代表，分别从长期施化肥（CF）和秸秆还田（HOF）的稻田土壤中提取DOM（DOMCF和DOMHOF），研究了DOMCF和DOMHOF分别对rNAu-2有氧氧化产生·OH的影响，以及DOMCF和DOMHOF在该过程中的转化差异。研究表明：在rNAu-2[Fe（Ⅱ）=1.2 mmol·L-1]氧化过程中DOMHOF更容易被矿化，其中，氧化8 h时DOMHOF被氧化形成CO2的累积量（以C计）为29.6 μg，高于DOMCF（16.9 μg）。DOMCF和DOMHOF均会抑制rNAu-2有氧氧化产生·OH，并且DOMHOF的抑制作用更明显。无DOM存在条件下，rNAu-2有氧氧化8 h的·OH累积量为26.06 μmol·L-1，高于rNAu-2/DOMCF（19.83 μmol·L-1）和rNAu-2/DOMHOF（17.07 μmol·L-1）体系（DOM为50 mg·L-1）。固液分离结果显示，rNAu-2与DOM或DOM-Fe3+的电子传递作用抑制了结构态Fe（Ⅱ）氧化形成·OH。三维荧光激发发射矩阵光谱（3DEEMs）分析表明，秸秆还田促进了水稻土腐殖质和富里酸类有机质的积累，并且氧化后的腐殖质和富里酸变化明显，而在DOMCF中几乎没有检测到这两者的存在。X射线光电子能谱（XPS）分析表明，·OH可以通过开环和羟基化机制加到芳香族结构或烯烃上，从而生成更多的含氧基团（C—O和C＝O）。因此，DOM的存在会抑制rNAu-2结构态Fe（Ⅱ）的氧化从而抑制·OH的形成，而秸秆还田的土壤DOM中含有更多易分解的有机质组分，更容易消耗·OH，同时释放更多的CO2。 |
| 英文摘要: |
| 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 DOMHOF 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 μmol·L-1）and rNAu-2/DOMHOF（17.07 μmol·L-1）systems（DOM concentration at 50 mg·L-1）. Solidliquid 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. |
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