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Liu X.,Northeast Forestry University | Liu X.,Forestry and Agriculture of Academy in the DaXingan Mountains | Hu H.Q.,Northeast Forestry University | Li W.H.,Forestry and Agriculture of Academy in the DaXingan Mountains | And 4 more authors.
Shengtai Xuebao/ Acta Ecologica Sinica | Year: 2014

Wetlands play a critical role in the global carbon cycle, wetland soil carbon stock accounting for about one-third of the global carbon storage, especially in the high latitude regions. DaXing'An Mountains region is located in an area of high latitude which is a major important area for global climate change. It has a cold and dry climate, small amount of soil microbes and low soil respiration rate. It is China's biggest warning area of global warming. Hence it is important to research on soil respiration and its relation to environmental factors in different types of wetlands in DaXing'An Mountains region. The seasonal dynamics of soil respiration were measured, respectively, in boreal typical wetlands birch (Betula platyphylla) island forest swamp and larch (Larix gmelinii) island forest marsh, using a static tank-gas chromatography method in the 2011 growing season. The Trenches Partition methosed was used to study the differences between the components of soil respiration. Our results showed that: Birch and larch island forest swamp soil respiration rate had obvious seasonal law in the growing season. Total soil respiration rates were 368.60 and 312.46 mg m-2h-1, heterotrophic respiration rates were 300.57 and 215.70 mg m-2h-1, autotrophic respiration rate were 68.03 and 96.76 mg m-2h-1. The peak period of soil respiration rates occurred during summer. Soil respiration was significantly correlated with temperature, while soil respiration was not significantly correlated with soil humidity. The soil temperatures rates of birch swamp were higher than the larch swamps, soil respiration rates of birch swamp were significantly correlated with soil temperature of 0—40 cm soil layer, which indicated the large space extent of microbial activity in this forest type; while soil respiration rates of larch swamp was significantly correlated with soil temperature of 5—15 cm soil layer, which indicated the small space extent of microbial activity and low contribution rate in this forest type. Soil respiration rate was 12.64 t/ hm2, heterotrophic respiration and autotrophic rates respiration were accounted for 81.5% and 18.5% of the total Soil respiration rate in birch swamp. Soil respiration rates was 10.61 t/ hm2, heterotrophic respiration and autotrophic respiration rates were accounted for 69.0% and 31.0% of the total soil respiration rates in larch swamps during the growing season. The soil respiration rate of soil microbes was significant higher than the soil respiration rate of root system in both forest types. The heterotrophic respiration (2.57 t/ hm2) of birch swamps was higher than that of larch swamp, while autotrophic respiration (0.54 t/ hm2) of birch swamps was lower than that of larch swamp when the soil respiration rate of birch swamps was larger than 2.03 t/ hm2of birch swamps. The autotrophic respiration rate of microbes was in dominant position and accounted for 68.0%—84.4% of total soil respiration, while the heterotrophic respiration of root systems accounted for 15.6%—32.0% of total soil respiration. The soil respiration rate was significantly correlated with soil SOC in the case of relatively stable temperature and soil moisture, the soil respiration rate increased with SOC. The biomass, coverage of herbaceous plants was consistent wit autotrophic respiration rate. The soil respiration rate was large when the large biomass and coverage. © 2014, Ecological Society of China. All rights reserved. Source

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