Abstract: Soil CO₂ emission is the production of microbial decomposition of soil organic substances and respiration of plant roots, which is effected by soil biotic and environmental factors. Daily changes in soil CO₂ emission from Mollic-gryic Cambisols was paralleled with daily trends of air temperature and soil surface temperature,but the peak of air temperature delay 2 hours than that of soil CO₂ emission and soil surface temperature. Soil surface temperature had strong effect on CO₂ emission and both exhibited a highly significant relationship. However, that were became weak at 5 cm undergroud. Soil temperature (at 0～30 cm, especially 5 cm), fungal hyphal biomas (within 0～20 cm), humic-c extant (within 0～20 cm) and live extant of aboveground cause seasonal variation of soil CO₂ emission and all exhibited a significant or extremely significant level to soil CO₂ emision. Over grazing made the rising of soil capacity and the decrease of porosity and organic substance, they can reduce soil CO₂ emission. The difference in CO₂ emission, stocking intensities were separately 2.55 and 5.35 sheeps/km-2 was significantly by F-test. Precipitation and soil moisture has not affected soil CO₂ emission from Mollic-gryic Cambisols. Sudden climate change would lead to strong fluctuation soil CO₂ emission.

Key words: Mollic Gryic cambisols, CO₂ emission, Alpine shrub

摘要： 暗沃寒冻雏形土土壤CO₂释放的日变化与气温及地表温度的日变化过程同步,只是气温日变化峰值推迟了2h。地表温度与土壤CO₂释放速率呈极显著正相关。暗沃寒冻雏形土土壤CO₂释入的季节动态受土壤温度(0～30cm,特别是10cm)、真菌菌丝生物量(0～20cm)、土壤有机碳现存量(0～20cm)和生物量的影响。它们均与土壤CO₂的释放速率呈显著或极显著的正相关关系。过度放牧使土壤容重增大,孔隙度和土壤有机碳贮量减小,从而降低土壤CO₂释放速率,方差分析结果表明,差异显著。而土壤湿度及降雨对土壤CO₂释放速率影响较小。

关键词: 暗沃寒冻雏形土, CO₂释放速率, 高寒灌丛