Effects Of Seasonal Snowcover And Adding Litter On Winter Soil Respiration In The Subalpine Forest

With the global climate change, soil respiration in winter is much more important to the regional and global carbon sequestration, especially in the warming winter and thinner snowcover. Because ecological processes in cold biomes are often more sensitive to global climate change than in those in warm biomes, especially to global warming, many studies carried out the experiments of soil respiration in polar and alpine tundra ecosystems, while soil respiration in alpine/subalpine forest are still poorly understood. In this study, the experiment was located in ditch Kaka (E103°40', N32°59,3200 m a.s.l.) in the western Sichuan, snow/snowcover conditions through the field to carry out a controlled gradient (snow layer thickness) and added Litter Material to assess the soil respiration in alpine/subalpine forest during winter. We found that:1) Soil respirations under snow-cover are controlled by moisture not temperature in these cold biomes.2) There were significant differences among the three snowcover patterns on soil respiration (p< 0.05). The change of soil respiration under the DS snowcover was the least of three snowcover (from 0.63 to 3.05μmol m-2 s-1; 105.12%), and the corresponding change under the NS (no snowcover) was the largest from 0.11 to 7.41,132.90%; and the corresponding value under the 30 cm snowcover (MS) was from 0.55 to 7.79,127.88%. These results indicated that soil respiration was on going during the winter, although less respiration value was observed, and different patterns of snowcover could affect the soil respiration in the winter. Thicker snowcover could limit the winter respiration, especially during the early spring, due to the snow melt and soil less temperature increased, thus the soil respiration under the thicker snowcover could be limited to a large extent.3) As for adding litter to this experiment, No statistic difference detected among the NL LL and ML on soil respiration from January to March, indicating that the method of adding litter could not affect the soil respiration in the winter but could exert a significant influence during the early spring (FApr.=19.626, p=0.000; FMay=18.329, p=0.000). Since March, more increase (31.69%) of respiration occurred at the soil with 20 g adding litter. This result indicated that adding litter could improve the soil respiration in early spring. Litter decomposability is probably to this.4) As is shown in the correlation between snowcover and adding litter on soil respiration, snowcover and adding litter could influence soil respiration respectively. Moreover, the dynamics of snow pattern could also affect the soil respiration, however, the respiration in subalpine and alpine forest is still poorly understood which need a profound studies. The result of increase of respiration at the 20 g adding litter indicated that Carbon-resource is the key force in the control of soil respiration in winter in the cold biomes.5) No "carbon deficit" detected in this region.