Effect of strong rainfalls on soil respiration in a typical temperate forest in Lesser Xing’an Mountains,northeast China

Forest soil respiration is an important component of ecosystem carbon cycle. Under the context of global climate change, extreme climate events present a high-rate tendency. How the change affects soil respiration in the forest ecosystem has attracted more and more attention. In order to investigate the response of soil respiration to strong rainfalls during different periods of the wet season, we used SF-3000 automated soil flux system to monitor different components of soil respiration in a typical temperate forest (spruce-fir-Korean pine forest) in Lesser Xing’an Mountains, northeast China. Environmental factors were also measured simultaneously. The results showed that, 1) soil respiration (Rs) was influenced by soil temperature and soil water content. The strong rainfalls altered the determining factors that control Rs. Soil water content was stimulated greatly by strong rainfalls. During the early period of wet season, Rs was merely disturbed by strong rainfalls, whereas it decreased Rs during the wet season and increased Rs after the wet season. 2) The influences of strong rainfalls on heterotrophic respiration/soil respiration (Rh/Rs) varied during different periods of the wet season. Compared to autotrophic respiration (Ra), strong rainfalls greatly inhibited Rh. 3) The relationship between Rs and soil temperature at 5 cm depth (T5) as well as soil water content at 5 cm depth (W5) could be better explained by an exponential equation which contains soil moisture parameter c. Strong rainfalls had varying effects on temperature sensitivities of Rs (Q10) during different periods of the wet season. The soil moisture sensitivity of Rs was decreased after rainfall. The moisture sensitivities (c) during different periods of the wet season were characterized as follow: wet season <, early wet season <, after the wet season.