环境因子对暗沃寒冻雏形土土壤CO_2释放速率的影响

Effect of Soil Circumstances Biogeochemical Factors on Carbon Dioxide Emission from Mollic-Gryic Cambisols

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2 h。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 10 cm)、真菌菌丝生物量 (0～ 2 0 cm)、土壤有机碳现存量 (0～ 2 0 cm)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

Soil CO 2 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 CO 2 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 CO 2 emission and soil surface temperature. Soil surface temperature had strong effect on CO 2 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 CO 2 emission and all exhibited a significant or extremely significant level to soil CO 2 emision. Over grazing made the rising of soil capacity and the decrease of porosity and organic substance, they can reduce soil CO 2 emission. The difference in CO 2 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 CO 2 emission from Mollic gryic Cambisols. Sudden climate change would lead to strong fluctuation soil CO 2 emission.