Comparative Study on Characteristics and Influencing Factors of Soil Respiration of Reed Wetlands in Yellow River Estuary and Liaohe River Estuary

Soil respiration rates of reed wetlands in the Yellow River Estuary and in the Liaohe River Estuary were determined with a Li-8100 Automated Soil CO2 Flux System in May and November, 2009, respectively, and reasons were analyzed for the difference in respiration rates between the two wetlands. Analytical results showed that: 1) Average soil respiration rate of the Yellow River Estuary was 1.06 μmol·m-2.s-1 in May and 0.24 μmol·m-2.s-1 in November, which was 17 times and twice as much as those in the Liaohe River Estuary, respectively. And main reasons leading to the difference included temperature, moisture and texture of soil, while nutrient elements were not a major influencing factors. 2) Soil respiration rate of the Yellow River Estuary decreased with the rising of soil temperature in May when soil temperature was relatively high, and exhibited no significant diurnal variation in November; the rate in May was 4 times than that in November, mainly influenced by soil temperature and variation in vegetation growth period. In the Liaohe River Estuary, the rate was severely inhibited by the high soil moisture and exhibited insignificant diurnal variation in May, while it increased with the rising of soil temperature in November; the rate in May was merely half that in November.