Dynamics of Soil N2O and CO2 Emissions in Response to Freeze–Thaw Intensity and Moisture Variations: A Laboratory Experiment

作者：Yuhua Kong, Shanshan Gong, Longfei Zhu, Haohao Wu, Keji Duan, Weiguo Cheng, D. A. Khoroshaev, Yong Lai, Xingkai Xu · 发表于：Forests · 年份：2025 · DOI：10.3390/f16030380 · 被引用次数：8 · 研究领域：Climate change and permafrost、Soil and Unsaturated Flow、Soil Carbon and Nitrogen Dynamics

Climate warming has led to more frequent soil freeze–thaw (FT) events in high-latitude and high-altitude regions, leading to significant pulse releases of greenhouse gasses (GHGs) such as nitrous oxide (N2O) and carbon dioxide (CO2) into the atmosphere. These pulse emissions exhibit unpredictable spatiotemporal variability, which are influenced by soil type, soil moisture and FT temperature. This study employed controlled laboratory experiments to investigate the effects of varying FT intensities (−10 °C/10 °C, −5 °C/5 °C, and a control at 0 °C/0 °C) and soil moisture levels (30%, 60%, and 90% water-filled pore space, WFPS) on the dynamics of soil N2O and CO2 emissions (measured daily), and the availability of carbon and nitrogen, microbial biomass, and enzyme activities (measured weekly) in the soils collected from two forest stands in the Changbai mountains of northeast China, a broadleaf and Korean pine (Pinus koraiensis Sieb. et Zucc.) mixed forest (BKPF) and an adjacent secondary white birch (Betula platyphylla Suk.) forest (WBF), where FT events frequently occur. Our findings reveal that a high FT intensity (−10 °C/10 °C) significantly increased N2O and CO2 emissions from BKPF and WBF soils. With increasing soil moisture, soil CO2 emissions peaked at 60% WFPS, while soil N2O emissions were the highest at 90% WFPS. Notably, pulse emissions of N2O were particularly intense under a high FT intensity and high moisture (i.e., 90% WFPS) in WBF soils, persisting for nearly 8 d...