[Short-term response of carbon emission to snow cover change in Calamagrostis angustifolia wetlands of Sanjiang Plain, Northeast China].

To understand the response of Calamagrostis angustifolia wetland of the Sanjiang Plain to changes in snow cover, we examined the greenhouse gases emission flux of the removed snow treatment (0 cm, RS), the added snow treatment (50 cm, AS) and the control (20 cm, CK) of a C. angustifolia wetland, and their relations with environmental factors with the method of the static chamber-gas chromatography. The results showed that soil temperature, soil water content, and carbon emissions were lowest during the snow-covering period under all treatments, and gradually increased with time. With the increases of time and snow thickness, soil temperature was rised and the difference of three treatments gradually was decreased. Soil water content of RS was always lower than that of CK and AS. AS and CK could promote soil CO ₂ emission compared with RS during and after snowmelt. The soil cumulative CH ₄ emissions differed little among the treatments. There was significant correlation between soil temperature and cumulative CO ₂ and CH ₄ emissions. With the increases of soil temperature, soil cumulative CO ₂ emission continued to increase and soil cumulative CH ₄ emission decreased firstly and then increased rapidly. Soil water content was significantly correlated with cumulative CO ₂ and CH ₄ emissions. As the soil moisture increased, the cumulative soil CO ₂ emission gradually increased, reaching a certain threshold and then flattening, while soil cumulative CH ₄ emission continuously increased.