藏东南色季拉山不同森林类型土壤CO2_排放

Soil CO_2 emission of different forest types in Sejila Mountains,southeast of Tibet

为阐明不同森林类型土壤碳排放变化特征及O层土壤对土壤碳排放的贡献,以藏东南色季拉山主要类型森林(冷杉、杜鹃、高山栎、云杉)为研究对象,设置移除和保留O层处理,分别测定其土壤碳排放量。结果表明:(1)供试的4种森林土壤均呈酸性(pH<6.0),且随着土壤层次的加深pH值逐渐增大;(2)土壤温、湿度变化具有单峰型日变化特征,最大值均出现在12:00—14:00,最小值出现在8:00—9:00;日变化尺度上,土壤CO_2排放速率同样表现为单峰型日变化特征,4种森林类型土壤CO_2排放速率均表现为保留O层>移除O层>O层,不同处理土壤CO_2排放速率之间差异达极显著水平(P<0.01);不同森林类型土壤累计碳通量变化特征与土壤CO_2排放速率变化规律基本一致。

In order to elucidate the characteristics of soil carbon emission in different forest types and effects of O layer soil on soil carbon emission,treatments removed and retained O layer were set up,and the carbon emissions of the main types of forest（ fir,rhododendron,alpine oak,spruce） in the Sejila mountains in southeastern of Tibet were measured,respectively. The results showed that：（ 1） Four kinds of forest soils were acidic（ pH 6. 0）,and the pH gradually increased with deepening of the soil;（ 2） Soil temperature and humidity changes had the characteristics of single peak diurnal variation,the maximum value appeared during 12： 00—14： 00,the minimum appears during 8： 00—9： 00; On diurnal variation scale,soil CO_2 emission rate also showed the diurnal variation characteristics of single peak type,and CO_2 emission rates of the four forest types were as follows： remain O layer remove O layer O layer,the differences of CO_2 emission rate between different treatments were extremely significant（ P 0. 01）; The characteristics of cumulative carbon flux in different forest types were consistent with the variation of soil CO_2 emission rate.