Microbial-explicit processes and refined perennial plant traits improve modeled ecosystem carbon dynamics

作者：Danielle Berardi, Melannie D. Hartman, Edward Brzostek, Carl J. Bernacchi, Evan H. DeLucia, Adam C. von Haden, I. B. Kantola, Caitlin E. Moore, Wendy H. Yang, T. W. Hudiburg, William J. Parton · 发表于：Geoderma · 年份：2024 · DOI：10.1016/j.geoderma.2024.116851 · 被引用次数：15 · 研究领域：Soil Carbon and Nitrogen Dynamics、Bioenergy crop production and management、Plant Water Relations and Carbon Dynamics

Globally, soils hold approximately half of ecosystem carbon and can serve as a source or sink depending on climate, vegetation, management, and disturbance regimes. Understanding how soil carbon dynamics are influenced by these factors is essential to evaluate proposed natural climate solutions and policy regarding net ecosystem carbon balance. Soil microbes play a key role in both carbon fluxes and stabilization. However, biogeochemical models often do not specifically address microbial-explicit processes. Here, we incorporated microbial-explicit processes into the DayCent biogeochemical model to better represent large perennial grasses and mechanisms of soil carbon formation and stabilization. We also take advantage of recent model improvements to better represent perennial grass structural complexity and life-history traits. Specifically, this study focuses on: 1) a plant sub-model that represents perennial phenology and more refined plant chemistry with downstream implications for soil organic matter (SOM) cycling though litter inputs, 2) live and dead soil microbe pools that influence routing of carbon to physically protected and unprotected pools, 3) Michaelis-Menten kinetics rather than first-order kinetics in the soil decomposition calculations, and 4) feedbacks between decomposition and live microbial pools. We evaluated the performance of the plant sub-model and two SOM cycling sub-models, Michaelis-Menten (MM) and first-order (FO), using observations of net ecosyst...