Argiroff William A, Zak Donald R, Pellitier Peter T, Upchurch Rima A, Belke Julia P
School for Environment and Sustainability, University of Michigan, Ann Arbor, Michigan, USA.
Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, Michigan, USA.
Ecol Lett. 2022 Feb;25(2):391-404. doi: 10.1111/ele.13923. Epub 2021 Nov 17.
Interactions between soil nitrogen (N) availability, fungal community composition, and soil organic matter (SOM) regulate soil carbon (C) dynamics in many forest ecosystems, but context dependency in these relationships has precluded general predictive theory. We found that ectomycorrhizal (ECM) fungi with peroxidases decreased with increasing inorganic N availability across a natural inorganic N gradient in northern temperate forests, whereas ligninolytic fungal saprotrophs exhibited no response. Lignin-derived SOM and soil C were negatively correlated with ECM fungi with peroxidases and were positively correlated with inorganic N availability, suggesting decay of lignin-derived SOM by these ECM fungi reduced soil C storage. The correlations we observed link SOM decay in temperate forests to tradeoffs in tree N nutrition and ECM composition, and we propose SOM varies along a single continuum across temperate and boreal ecosystems depending upon how tree allocation to functionally distinct ECM taxa and environmental stress covary with soil N availability.
土壤氮（N）有效性、真菌群落组成和土壤有机质（SOM）之间的相互作用调节着许多森林生态系统中的土壤碳（C）动态，但这些关系中的背景依赖性阻碍了通用预测理论的发展。我们发现，在北温带森林自然无机氮梯度上，随着无机氮有效性的增加，具有过氧化物酶的外生菌根（ECM）真菌数量减少，而木质素分解真菌腐生菌则无响应。木质素衍生的SOM和土壤C与具有过氧化物酶的ECM真菌呈负相关，与无机氮有效性呈正相关，这表明这些ECM真菌对木质素衍生SOM的分解减少了土壤C的储存。我们观察到的相关性将温带森林中的SOM分解与树木氮营养和ECM组成的权衡联系起来，并且我们提出，根据树木对功能不同的ECM类群的分配以及环境胁迫如何随土壤氮有效性共同变化，SOM在温带和北方生态系统中沿着单一连续体变化。
