ENVIRONMENTAL INTERPRETATION OF SEASONAL VARIATIONS IN SOIL RESPIRATION IN DIFFERENT FOREST STANDS OF THE ZHEGAO RIVER WETLANDS

To investigate the influences of environmental factors on wetland soil respiration, seasonal variations in soil respiration (Rs), heterotrophic respiration (Rh), and autotrophic respiration (Ra) were analyzed in Populus canadensis Moench (PCM), Salix matsudana Koidz (SMK), Metasequoia glyptostroboides Hu (MGH), and Pinus elliottii Engelm (PEE) forests located in the Zhegao River wetlands.The results indicated that the Rs of different woodlands was highest in summer and lowest in winter.The annual mean Rs values were highest in MGH and lowest in PEE, where the contribution of Rh was > 57.9%.Seasonal changes in Rh were significant in MGH and PEE, and negligible in SMK, while the Ra in PEE reached the highest flux in autumn, and other woodlands had the highest fluxes in summer.Correlations between soil respiration and soil temperature were higher than those with soil moisture across the four forest stands.Furthermore, the temperature sensitivity coefficients (Q10) were greater in all three deciduous forests compared with the coniferous forest (PEE).The synergistic impacts of soil temperature and moisture on soil respiration were greater than their individual effects.