| 亚热带丘陵区微塑料输入对稻麦轮作农田土壤N2O排放及产生路径的影响 |
| 摘要点击 1714 全文点击 31 投稿时间：2025-04-02 修订日期：2025-07-11 |
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| 中文关键词 稻麦轮作农田 N2O排放速率 产生路径 潜在硝化速率 潜在反硝化速率 微塑料（MPs） |
| 英文关键词 rice-wheat rotational cropland N2O emission rates production pathways potential nitrification rate potential denitrification rate microplastics（MPs） |
| DOI 10.13227/j.hjkx.202504038 |
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| 中文摘要 |
| 稻麦轮作农田是我国重要的粮食生产体系，不仅保障粮食安全，也因高氮投入和频繁耕作成为农业源N2O排放的重要来源. 农用地膜残留、有机肥施用及污水灌溉等措施加剧了农田微塑料污染，土壤微塑料通过改变理化性质和微生物过程，影响N2O排放. 然而，稻麦轮作体系中微塑料污染对N2O排放的影响机制尚不明确. 为此，以亚热带丘陵区典型稻麦轮作农田土壤为对象，探究传统石油基聚乙烯（PE）和全生物可降解聚乳酸（PLA）微塑料输入对土壤理化性质、硝化-反硝化速率、N2O排放及产生路径的影响. 结果表明，微塑料处理显著改变土壤性质与氮转化过程. 培养期间，土壤pH下降，铵态氮（NH4+-N）及硝态氮（NO3--N）含量上升，土壤有机质（SOM）在5% PE/PLA处理下显著增加，PLA对土壤因子的影响强于PE. 土壤潜在硝化速率（PNR）上升、土壤潜在反硝化速率（PDR）下降趋势明显，PLA影响更显著. N2O排放呈先升后降趋势，15~30 d阶段PE高于CK （P<0.05），同丰度PLA N2O排放高于PE（P<0.05）. 异养反硝化为主要N2O来源（64.5%~76.5%），1% PE促进自养硝化. 功能基因方面，1% PE显著提高amoA-AOA丰度，而PLA在培养第15~31 d降低其表达；1%和2.5% PE/PLA降低amoA-AOB丰度；PLA处理下nirK和nirS丰度通常高于PE. 偏最小二乘路径模型（PLS-PM）分析表明，反硝化基因、土壤性质与PDR显著影响N2O排放，解释N2O排放变异的77%. 总体上，PLA通过强化反硝化过程，较PE更显著提升土壤N2O排放. |
| 英文摘要 |
| The paddy-wheat rotation system is a key grain production model in China, playing a vital role in ensuring national food security. However, due to high nitrogen (N) inputs, it has become a major source of agricultural N2O productions. Agricultural practices such as plastic film mulching, organic fertilizer application, and sewage irrigation have exacerbated microplastic pollution in croplands. Microplastics in soil can alter physicochemical properties and microbial processes, thereby affecting N2O productions. However, the mechanisms by which microplastic pollution influences N2O productions in paddy-wheat rotation systems remain unclear. In this study, we investigated the effects of inputs of conventional petroleum-based polyethylene (PE) and fully biodegradable polylactic acid (PLA) microplastics on soil physicochemical properties, nitrification-denitrification rates, N2O productions, and their production pathways in typical paddy-wheat rotation soils of a subtropical hilly region. The results showed that microplastic treatments significantly altered soil properties and nitrogen transformation processes. During incubation, soil pH decreased, while concentrations of ammonium nitrogen (NH4+-N) and nitrate nitrogen (NO3--N) increased. Soil organic matter (SOM) significantly increased under 5% PE/PLA treatments, with PLA exerting a stronger influence on soil parameters than PE. Soil potential nitrification rate (PNR) increased, while potential denitrification rate (PDR) showed a decreasing trend, with PLA having a more pronounced effect. N2O productions exhibited a rise-and-fall pattern, with emissions under PE significantly higher than the control (CK) during days 15-30 (P<0.05). At the same concentration, PLA induced higher N2O productions than PE (P<0.05). Heterotrophic denitrification was the dominant N2O source (64.5%-76.5%), while 1% PE enhanced autotrophic nitrification. Regarding functional genes, 1% PE significantly increased the abundance of amoA-AOA, whereas PLA suppressed its expression during days 15-31. Both 1% and 2.5% PE/PLA treatments reduced the abundance of amoA-AOB, while nirK and nirS abundances were generally higher under PLA than PE treatments. Partial least squares path modeling (PLS-PM) revealed that denitrification genes, soil properties, and PDR had significant effects on N2O productions, collectively explaining 77% of the variation in N2O productions. Overall, PLA microplastics enhanced denitrification processes more strongly than PE, resulting in greater N2O productions from the soil. |
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