TY - JOUR

T1 - Thresholds and interactive effects of soil moisture on the temperature response of soil respiration

AU - Lellei-Kovács, Eszter

AU - Kovács-Láng, Edit

AU - Botta-Dukát, Zoltán

AU - Kalapos, Tibor

AU - Emmett, Bridget

AU - Beier, Claus

N1 - Funding Information: Support from the following research grants is acknowledged: EU FW5 VULCAN project ( www.vulcanproject.com ), NKFP grant from the Hungarian Government.

PY - 2011

Y1 - 2011

N2 - Ecosystem carbon exchange is poorly understood in low-productivity, semiarid habitats. Here we studied the controls of soil temperature and moisture on soil respiration in climate change field experiment in a sandy forest-steppe. Soil CO2 efflux was measured monthly from April to November in 2003-2008 on plots receiving either rain exclusion or nocturnal warming, or serving as ambient control. Based on this dataset, we developed and compared empirical models of temperature and moisture effects on soil respiration. Results suggest that in this semiarid ecosystem the main controlling factor for soil CO2 efflux is soil temperature, while soil moisture has less, although significant effect on soil respiration. Clear thresholds for moisture effects on temperature sensitivity were identified at 0.6, 4.0 and 7.0vol% by almost each model, which relate well to other known limits for biological activity in this sandy soil. The relationship between soil respiration and temperature was better described by the Lloyd-Taylor or the Gaussian functions compared to exponential function. Involving additive and interactive soil moisture effects further improved model fitting. Similarly to other low productivity semiarid ecosystems, annual soil carbon efflux values estimated by the different models were rather low (between 123.1 and 139.8g C m-2 yr-1 as multi-year averages).

AB - Ecosystem carbon exchange is poorly understood in low-productivity, semiarid habitats. Here we studied the controls of soil temperature and moisture on soil respiration in climate change field experiment in a sandy forest-steppe. Soil CO2 efflux was measured monthly from April to November in 2003-2008 on plots receiving either rain exclusion or nocturnal warming, or serving as ambient control. Based on this dataset, we developed and compared empirical models of temperature and moisture effects on soil respiration. Results suggest that in this semiarid ecosystem the main controlling factor for soil CO2 efflux is soil temperature, while soil moisture has less, although significant effect on soil respiration. Clear thresholds for moisture effects on temperature sensitivity were identified at 0.6, 4.0 and 7.0vol% by almost each model, which relate well to other known limits for biological activity in this sandy soil. The relationship between soil respiration and temperature was better described by the Lloyd-Taylor or the Gaussian functions compared to exponential function. Involving additive and interactive soil moisture effects further improved model fitting. Similarly to other low productivity semiarid ecosystems, annual soil carbon efflux values estimated by the different models were rather low (between 123.1 and 139.8g C m-2 yr-1 as multi-year averages).

KW - Drought

KW - Empirical model

KW - Soil carbon efflux

KW - Threshold values

U2 - 10.1016/j.ejsobi.2011.05.004

DO - 10.1016/j.ejsobi.2011.05.004

M3 - Journal article

AN - SCOPUS:79960579852

VL - 47

SP - 247

EP - 255

JO - European Journal of Soil Biology

JF - European Journal of Soil Biology

SN - 1164-5563

IS - 4

ER -