Initial Effects of Rainfall Reduction on Soil Respiration in Quercus mongolica Forest in Sanjiang Plain
[Objective]This study investigated the response of soil respiration to drought conditions and elucidated the feedback relationship between global climate change and soil carbon emissions.[Method]The research focused on the secondary Quercus mongolica forest in the Sanjiang plain,employing an in forest rain reduction technique to simulate drought scenarios.The LI-8100 soil CO2 flux measurement system was utilized to monitor soil respiration rates from May to September 2023,examining how soil temperature,soil volumetric water content,and various components of soil respiration respond to reduced rainfall.[Result]The soil temperature and soil volumetric water content showed a decreasing trend after rain reduction treatment,and the soil heterotrophic respiration rate was not significantly affected by rain reduction treatment,but the total soil respiration rate was significantly decreased.The seasonal variation of soil respiration rate was consistent with that of soil temperature.Soil respiration rate had a significant exponential correlation with soil temperature(P＜0.01),and a significant binomial linear correlation with soil volumetric water content(P＜0.05).The sensitivity of soil total respiration temperature decreased due to rainfall reduction.Two-factor ANOVA analysis of variance showed that the main effect existed when rainfall reduction was taken as independent variable(P＜0.05),but there was no significant interaction between them(P＞0.05).[Conclusion]Short-term reductions in rainfall markedly suppressed soil respiration within the Quercus mongolica forest of the Sanjiang plain,consequently,during early simulated drought conditions,carbon emission rates from this natural secondary forest may decline significantly.The results can provide a theoretical framework for managing Quercus mongolica forests while offering data support for accurately assessing carbon sequestration potential under climate change scenarios in northeastern China.
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