Department of Biology, Indiana University Bloomington, Bloomington, IM, USA.
Department of Ecology, Evolution and Behavior, University of Minnesota Twin Cities, Minneapolis, MN, USA.
Ecol Lett. 2021 Apr;24(4):626-635. doi: 10.1111/ele.13651. Epub 2021 Jan 25.
Roots promote the formation of slow-cycling soil carbon (C), yet we have a limited understanding of the magnitude and controls on this flux. We hypothesised arbuscular mycorrhizal (AM)- and ectomycorrhizal (ECM)-associated trees would exhibit differences in root-derived C accumulation in the soil, and that much of this C would be transferred into mineral-associated pools. We installed δ C-enriched ingrowth cores across mycorrhizal gradients in six Eastern U.S. forests (n = 54 plots). Overall, root-derived C was 54% greater in AM versus ECM-dominated plots. This resulted in nearly twice as much root-derived C in putatively slow-cycling mineral-associated pools in AM compared to ECM plots. Given that our estimates of root-derived inputs were often equal to or greater than leaf litter inputs, our results suggest that variation in root-derived soil C accumulation due to tree mycorrhizal dominance may be a key control of soil C dynamics in forests.
根系促进了慢循环土壤碳（C）的形成，但我们对这种碳通量的规模和控制因素了解有限。我们假设丛枝菌根（AM）和外生菌根（ECM）相关的树木在根系衍生的碳积累方面会表现出差异，而且这些碳中的大部分将被转移到矿物结合的库中。我们在六个美国东部森林的菌根梯度上安装了 δ C 富集的生长芯（n=54 个样地）。总的来说，AM 主导的样地中根系衍生的 C 比 ECM 主导的样地高 54%。这导致 AM 样地中潜在的慢循环矿物结合库中根系衍生的 C 比 ECM 样地多近一倍。鉴于我们对根系衍生输入的估计通常等于或大于叶凋落物输入，我们的结果表明，由于树木菌根优势导致的根系衍生土壤 C 积累的变化可能是森林土壤 C 动态的关键控制因素。
