Responses of soil respiration and its temperature/moisture sensitivity to precipitation in three subtropical forests in southern China

Abstract

Both long-term observation data and model simulations suggest an increasing chance of serious drought in the dry season and extreme flood in the wet season in southern China, yet little is known about how changes in precipitation pattern will affect soil respiration in the region. We conducted a field experiment to study the responses of soil respiration to precipitation manipulations – precipitation exclusion to mimic drought, double precipitation to simulate flood, and ambient precipitation as control (abbr. EP, DP and AP, respectively) – in three subtropical forests in southern China. The three forest sites include Masson pine forest (PF), coniferous and broad-leaved mixed forest (MF) and monsoon evergreen broad-leaved forest (BF). Our observations showed that altered precipitation strongly influenced soil respiration, not only through the well-known direct effects of soil moisture on plant and microbial activities, but also by modification of both moisture and temperature sensitivity of soil respiration. In the dry season, soil respiration and its temperature sensitivity, as well as fine root and soil microbial biomass, showed rising trends with precipitation increases in the three forest sites. Contrarily, the moisture sensitivity of soil respiration decreased with precipitation increases. In the wet season, different treatments showed different effects in three forest sites. The EP treatment decreased fine root biomass, soil microbial biomass, soil respiration and its temperature sensitivity, but enhanced soil moisture sensitivity in all three forest sites. The DP treatment significantly increased soil respiration, fine root and soil microbial biomass in the PF only, and no significant change was found for the soil temperature sensitivity. However, the DP treatment in the MF and BF reduced soil temperature sensitivity significantly in the wet season. Our results indicated that soil respiration would decrease in the three subtropical forests if soil moisture continues to decrease in the future. More rainfall in the wet season could have limited effect on the response of soil respiration to the rising of temperature in the BF and MF

Effects of continuous drought stress on soil respiration in a tropical rainforest in southwest China

“…Consistent with this expectation, many precipitation reduction experiments have shown that SR decreases with decreasing moisture levels (Cattanio et al 2002;Borken et al 2006; Jiang et al 2013). In the present study, we found that experimental drought significantly increased soil respiration in the rainy season, but had no significant impact on soil respiration in the dry season.…”

“…Both laboratory and field experiments have shown that rising temperatures stimulate CO 2 release from soils, which in return reinforces global warming (Luo 2007;Balser and Wixon 2009;Wood and Silver 2012;. However, precipitation manipulation experiments have shown that the effects of precipitation on SR are variable and ecosystem-dependent (Borken et al 2006;Zhou et al 2006;Sotta et al 2007;Davidson et al 2008;Cleveland et al 2010;van Straaten et al 2010van Straaten et al , 2011Jiang et al 2013), indicating the complexity of the SR response to soil moisture. In addition, soil moisture can vary widely even at seasonal scales and within a single ecosystem, resulting in a seasonal dependence of the SR response to rainfall variations.…”

Simulated rain addition modifies diurnal patterns and temperature sensitivities of autotrophic and heterotrophic soil respiration in an arid desert ecosystem

“…However, evidence suggests that Q 10 value varies in space and time (Raich and Schlesinger, 1992;Xu and Qi, 2001;Chen et al, 2010) because Q 10 is regulated by various abiotic and biotic factors, such as soil moisture and plant physiological activity Davidson et al, 1998;Xu and Qi, 2001;Jia and Zhou, 2009;Subke and Bahn, 2010). Thus, the increased rainfall in arid and semiarid regions in northwestern China under future climate scenarios is expected to modify the Q 10 value (Curiel Yuste et al, 2003;LelleiKovacs et al, 2011;Jiang et al, 2013). Many experimental studies have investigated the response of daily Q 10 to rainfall variability (Liu et al, 2008;Zhang et al, 2010;Bowling et al, 2011;Li et al, 2011;Thomas et al, 2011;Shi et al, 2012;Vargas et al, 2012).…”

Carbon and Water Budgets in Multiple Wheat-Based Cropping Systems in the Inland Pacific Northwest US: Comparison of CropSyst Simulations with Eddy Covariance Measurements

“…Large rainfall amounts and frequent rainfall events increased the simulated R eco by enhancing R h during the oMGS and R a during the MGS at MMTN. The frequent rainfall events during the oMGS greatly enhanced soil microbial activity under the disturbed soil conditions at MMTN, which was also observed by Calderon and Jackson (2002); Zhou et al (2006); Jiang et al (2013), and Gong et al (2015). In addition, MMTN had sufficient water for winter wheat growth, therefore R a was also much higher compared to LIND where both crop growth and crop respiration were limited by the dry summer.…”