入侵植物薇甘菊对土壤主要温室气体排放的影响:真菌主导N2O排放与低CO2当量特征

Influence of the Invasive Plant Mikania micrantha on Major Soil Greenhouse Gas Emissions: Fungal-dominated N2O Emissions and Low CO2-Equivalent Characteristics

摘要:

为揭示植物生长对土壤N₂O和CO₂排放的影响，通过野外和盆栽试验相结合，对入侵植物薇甘菊(Mikania micrantha)及其竞争植物粉葛(Pueraria lobata var. thomsonii)和红薯(Ipomoea batatas)的土壤温室气体排放进行了研究。结果表明，薇甘菊生长土壤的CO₂当量排放显著低于粉葛和红薯，显示出更低的温室效应潜势；真菌对N₂O排放的相对贡献(79.3%)显著高于细菌(58.1%)；随机森林模型揭示土壤总氮(TN)、硝态氮(NO₃^--N)和铵态氮(NH₄⁺-N)是温室气体排放的核心驱动因子(解释度>11%)，与CO₂当量排放量呈显著正相关(R²=0.49~0.82)。薇甘菊生长土壤的温室气体排放效应与对照物种的选择密切相关。与本地植物粉葛和红薯相比，薇甘菊生长土壤表现出更低的温室效应潜势，这可能与不同植物的氮利用策略和氮循环微生物群落调控机制有关。这为入侵植物生态效应的评估提供了重要参考，但需结合更多物种和长期观测进一步验证。

Abstract:

To reveal the impact of plant growth on soil N₂O and CO₂ emissions, a combined field and pot experiment was conducted to study the soil greenhouse gas emissions of Mikania micrantha and its competing plants, Pueraria lobata var. thomsonii and Ipomoea batatas. The results showed that the CO₂ equivalent emissions from the soil where M. micrantha grew were significantly lower than those from the soil where P. lobata var. thomsonii and I. batatas grew, indicating a lower greenhouse effect potential. The relative contribution of fungi to N₂O emissions (79.3%) was significantly higher than that of bacteria (58.1%). The random forest model revealed that total soil nitrogen (TN), nitrate nitrogen (NO₃^--N), and ammonium nitrogen (NH₄⁺-N) were the core driving factors of greenhouse gas emissions (explaining more than 11%), and were significantly positively correlated with CO₂ equivalent emissions (R²=0.49-0.82). The greenhouse gas emission effect of the soil where M. micrantha grows is closely related to the choice of control species. Compared with the local plants P. lobata var. thomsonii and I. batatas, the soil where M. micrantha grows shows a lower greenhouse effect potential, which may be related to the different nitrogen utilization strategies and nitrogen cycling microbial community regulation mechanisms of different plants. This provides an important reference for the assessment of the ecological effects of invasive plants, but further validation is needed by combining more species and long-term observations.