Effects of Water Change on Decomposition and CO₂ Emission of Litter of Carex muliensis in Zoige Alpine Wetland

Litter decomposition is an important part of material circulation and energy flowing in wetland ecosystem and one of the key processes to regulate global carbon balance. The litters of Carex muliensis in Zoige alpine wetland were collected, and the weightlessness rate and the CO₂ emission with different water volumes and watering frequencies were measured to explore the response of litter decomposition to water change. The results show that there was no significant effect of water change on the litter weightlessness rate. The litter weightlessness rate under different drying-rewetting cycle was between 31.64%-34.26%. The water volumes, watering frequency and their interaction significantly affected the CO₂ emission during the litter decomposition (P < 0.05). The CO₂ cumulative emission was higher under the high water volumes than the low water volumes treatment. Under the high water volumes, the decrease of watering frequency significantly promoted the CO₂ cumulative emission(P < 0.05). The CO₂ emission was (5.28±0.24) and (10.77±0.64) g·kg^-1 under the high and the low watering frequency treatment, respectively. Therefore, changes of precipitation patterns in future, including altered precipitation volumes and frequency, will have an important impact on the litter decomposition and the CO₂ emission of Zoige alpine wetland.