Abstract. Tropical forests contribute significantly to the emission and uptake of carbon dioxide (CO₂), methane (CH₄), and nitrous oxide (N₂O). However, studies on the soil environmental controls of greenhouse gases (GHGs) from African tropical forest ecosystems are still rare. The aim of this study was to disentangle the regulation effect of soil nutrients on soil GHG fluxes in a tropical forest in northwestern Uganda. Therefore, a large-scale nutrient manipulation experiment (NME) based on 40 m × 40 m plots with different nutrient addition treatments (nitrogen (N), phosphorus (P), N + P, and control) was established. Soil CO₂, CH₄, and N₂O fluxes were measured monthly using permanently installed static chambers for 14 months. Total soil CO₂ fluxes were partitioned into autotrophic and heterotrophic components through a root trenching treatment. In addition, soil temperature, soil water content, and mineral N were measured in parallel to GHG fluxes. N addition (N, N + P) resulted in significantly higher N₂O fluxes in the transitory phase (0–28 days after fertilization, p 2O fluxes. P fertilization marginally and significantly increased transitory (p = 0.052) and background (p = 0.010) CH₄ consumption, probably because it enhanced methanotrophic activity. Addition of N and P together (N + P) resulted in larger CO₂ fluxes in the transitory phase (p = 0.010), suggesting a possible co-limitation of N and P on soil respiration. Heterotrophic (microbial) CO₂ effluxes were significantly higher than the autotrophic (root) CO₂ effluxes (p 2 effluxes compared to roots (p

中文翻译：

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营养限制限制热带森林的土壤温室气体通量：乌干达生态系统规模的养分操纵实验的证据

摘要。热带森林对二氧化碳（CO ₂），甲烷（CH ₄）和一氧化二氮（N ₂ O）的排放和吸收做出了重要贡献。但是，关于非洲热带森林生态系统中温室气体（GHG）的土壤环境控制的研究仍然很少。这项研究的目的是要弄清乌干达西北部热带森林中土壤养分对土壤温室气体通量的调节作用。因此，基于40 m×40 m地块，采用不同的养分添加处理（氮（N），磷（P），N + P和对照），建立了大规模养分操纵实验（NME）。土壤CO ₂，CH ₄和N ₂使用永久性安装的静室连续14个月每月测量一次O通量。通过根沟处理将土壤总CO ₂通量分为自养和异养成分。另外，平行于温室气体通量测量土壤温度，土壤水分和矿质氮。氮的添加（N，N + P）在过渡期（受精后0-28天，p  2O通量）导致N ₂ O通量显着增加。P施肥略有增加，过渡期（p  = 0.052）和背景（p  = 0.010）CH _4的消耗，可能是因为它增强了甲烷营养活性，将N和P加在一起（N + P）会产生较大的CO在过渡阶段有_2个通量（p  = 0.010），表明氮和磷在土壤呼吸中可能存在共限制。异养（微生物）CO ₂流出量显着高于自养（根）CO ₂流出量（ 与根相比，p 2流出量（p