Soil respiration sensitivities to water and temperature in a revegetated desert

Abstract

Soil respiration in water-limited ecosystems is affected intricately by soil water content (SWC), temperature, and soil properties. Eight sites on sand-fixed dunes that revegetated in different years since 1950s, with several topographical positions and various biological soil crusts (BSCs) and soil properties, were selected, as well as a moving sand dune (MSD) and a reference steppe in the Tengger Desert of China. Intact soil samples of 20 cm in depth were taken and incubated randomly at 12 levels of SWC (0 to 0.4 m 3 m À3 ) and at 9 levels of temperature (5 to 45°C) in a growth chamber; additionally, cryptogamic and microbial respirations (R M ) were measured. Total soil respiration (R T , including cryptogamic, microbial, and root respiration) was measured for 2 years at the MSD and five sites of sand-fixed dunes. The relationship between R M and SWC under the optimal SWC condition (0.25 m 3 m À3 ) is linear, as is the entire range of R T and SWC. The slope of linear function describes sensitivity of soil respiration to water (SRW) and reflects to soil water availability, which is related significantly to soil physical properties, BSCs, and soil chemical properties, in decreasing importance. Inversely, Q 10 for R M is related significantly to abovementioned factors in increasing importance. However, Q 10 for R T and respiration rate at 20°C are related significantly to soil texture and depth of BSCs and subsoil only. In conclusion, through affecting SRW, soil physical properties produce significant influences on soil respiration, especially for R T . This indicates that a definition of the biophysical meaning of SRW is necessary, considering the water-limited and coarse-textured soil in most desert ecosystems.

Diurnal dynamics of soil respiration and the influencing factors for three land-cover types in the hinterland of the Taklimakan Desert, China

“…Although desert ecosystem is generally low in soil organic carbon content, it plays an important role in soil carbon cycle (Liu et al, 2015). There are some recent researches on soil respiration in desert areas (e.g., Sierra, 2012;Jia et al, 2013;Zhang et al, 2015). A pervious study showed that soil respiration rate (Rs) in desert areas is relatively high in fixed sandy land, relatively low in semi-fixed sandy and lowest in shifting sandy land (Li et al, 2008).…”

“…It was reported that a significant hysteresis effect exists between Rs and Ts (Subke et al, 2003;Jia et al, 2013), and low levels of Ws could increase the degree of hysteresis (Phillips et al, 2011;Wang et al, 2013). Thus, Ws is of great importance in influencing Rs in desert ecosystems (Cable et al, 2011;Zhang et al, 2015). Recent studies proposed that desert ecosystems, which have long been neglected in the studies of global carbon budget, exhibit strong downward fluxes into the ground and therefore might be a significant carbon sink (Jasoni et al, 2005;Stone, 2008;Wohlfahrt et al, 2008;Ma et al, 2014).…”

Soil respiration variation along an altitudinal gradient in Italian Alps: Disentangling forest structure and temperature effects

“…Since then, other studies have investigated and quantified the impact of productivity on SR modeling [10, 11]. Apart from productivity, SR is influenced by different abiotic and biotic factors such as soil temperature, moisture, and microbial community, introducing a considerable uncertainty in SR estimates [12,13,14]. Among these factors, the temperature has been the most often studied factor affecting respiratory processes [15,16].…”

“…It plays an essential role in the soil organic matter distribution and may dampen the effects of climate change [14,22,23,24, 25]. In general, temperature declines with elevation, thus elevation gradient has been used to assess soil respiration response to temperature in several studies [12,26,27,28]. These studies indicate that CO2 exchange between soil and atmosphere varies along climatic gradients and that temperature sensitivity (Q10) of SR increases with elevation.…”

Monitoring water content dynamics of biological soil crusts

“…Castillo-Monroy et al (2011) used 5-cm-long TDR sensors and EC-5 sensors (Decagon Devices, Pullman, Wash.) installed vertically into the soil in several plots to measure water content. They found that the sensor provided reasonable estimates of volumetric water content at their field site, but their sensors may have sampled some biocrusts and soils below where biocrust is concentrated Zhang et al (2015). used 20-cm-long (Theta®) probes to measure water content of biocrusts and subsoil in the Tengger Desert of China.…”