Soil respiration efflux of fencing grasslands in the Xilamuren regions

ACE soil respiration measurement system was used to monitor the diurnal changes of the soil respiration rate of fencing grassland from the end of April to the early October every ten days in Xilamuren regions and the correlation relationships between the soil respiration rate and soil temperature and moisture were discussed in this study. This study indicated that diurnal changes of soil respiration was onepeak curve with the highest value at 12:00-14:00 and the lowest value at 1:00-3:00. The soil respiration flux was different day and night at the different phonological stage and showed a negative value while soil temperature was under 0 ℃, implying that the increase in observation frequency of soil respiration observation and sighting into the related mechanism were helpful to estimate accurately the whole year carbon flux. Soil respiration rate showed a quadratic function with soil water content and the theoretical highest respiration rate was 456.2 mg/(m2h) when soil water content was 21%, coinciding with field waterholding capacity with 20%. During growing season, Q10 value were between 1.16 and 6.28, and showed a quadratic function with soil water content, differing from previous study results, which would be a important guidance to soil respiration under global change.