Effects of High Soil Water Content and Temperature on Soil Respiration

Abstract

The aim of this study was to quantify the effects of high soil water content and soil temperature on soil respiration. With an automatic system, soil respiration, soil water content, and soil temperature at 5-cm depth were measured at 10-min intervals for 22 days. The measurements were carried out at three locations with high soil water content and soil temperature. Results showed that soil respiration and soil water content were negatively correlated (P < 0.01); rainfall did not stimulate any obvious pulse of soil respiration. There was an obvious hysteresis effect between soil respiration and soil temperature. Without considering the hysteresis effect, the temperature dependence parameter (q(10)) of soil respiration on soil temperature was underestimated. With the consideration of the hysteresis effect between soil temperature and soil respiration, the estimated q(10) values were in the range of 1.2 to 2.1, and the estimated basal respiration values were in the range of 0.5 to 2.5 mu mol m(-2) sec(-1) for the three measurement points. Based on more than 2,200 data points, reasonable relationships in the diurnal scale were established between soil respiration and soil water content, as well as soil temperature. The relationships should be useful to estimate soil respiration based on soil temperature and moisture data.