Experimental Soil Warming Impacts Soil Moisture and Plant Water Stress and Thereby Ecosystem Carbon Dynamics

作者：W. J. Riley, Jing Tao, Z. A. Mekonnen, R. F. Grant, Eoin Brodie, Elaine Pegoraro, Margaret Torn · 发表于：Journal of Advances in Modeling Earth Systems · 年份：2025 · DOI：10.1029/2024ms004714 · 被引用次数：7 · 研究领域：Plant Water Relations and Carbon Dynamics、Soil Carbon and Nitrogen Dynamics、Soil and Unsaturated Flow

Abstract Experimental soil heating experiments have found a consistent increase in soil‐surface CO 2 emissions ( F s ), but inconsistent soil organic carbon (SOC) responses. Interpretation of heating effects is complicated by spatial heterogeneity and soil moisture, nitrogen availability, and microbial and plant responses. Here we applied a mechanistic ecosystem model to interpret heating impacts on a California forest subjected to 1 m deep, 4°C heating. The model accurately simulated control‐plot CO 2 fluxes, SOC stocks, fine root biomass, soil moisture, and soil temperature, and the observed increases in F s and decreases in fine root biomass. We show that a complex suite of interactions can lead to a consistent increase in F s (∼17%) over the 5‐year study period, with very small changes in SOC stocks (<1%). Modeled increases in leaf water stress from soil drying reduced GPP and NPP. The resulting reduction in leaf and fine root allocation increased fine root litter inputs to the soil and reduced root exudation. Soil heating led to about a 50% larger increase in root autotrophic respiration than in heterotrophic respiration, with the heating effect on both these fluxes decreasing over the simulation period. Increased heterotrophic respiration led to increased soil N availability and plant N uptake. These heating responses are mechanistically linked, of magnitudes that can affect ecosystem dynamics, and long‐term observations of them are rarely made. Therefore, we conclud...