Effects of environmental and biotic factors on soil respiration in a coastal wetland in the Yellow River Delta, China

Using the Li-8150 multichannel automatic soil CO2efflux system, soil respiration was measured continuously over a one-year period in a coastal wetland in the Yellow River Delta, China. Environmental and biological factors were measured simultaneously, including temperature, soil water content, aboveground biomass and leaf area index. The results showed that the diurnal variation of soil respiration presented a single-peak curve, but it appeared as multiple peaks when disturbed by soil freezing and surface flooding. Soil respiration showed obvious seasonal dynamics and a single peak curve. The average annual soil respiration was 0.85 μmol CO2·m-2·s-1, and the mean soil respiration rate was 1.22 μmol CO2·m-2·s-1during the growing season. On one-year scale, soil temperature was a major factor influencing soil respiration in the coastal wetland, which explained 87.5% of the variation in soil respiration. On the growing season scale, soil water content and leaf area index accounted for 85% of the seasonal variation of soil respiration.