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西藏亚高山暗针叶林森林植被是我国重要的生态屏障,对全球陆地生态系统的碳收支平衡起着举足轻重的作用。该研究选取西藏色季拉山2种最典型的天然暗针叶林:急尖长苞冷杉(Abies georgei var.smithii)和林芝云杉(Picea likiangensis var.linzhiensis)为研究对象,测定其土壤有机碳含量和微生物量碳含量,并动态监测其土壤呼吸及其各呼吸组分速率,结果表明:2种植被类型的SOC含量和SMBC含量均具有明显的表聚性,表层(0~20 cm)SOC含量分别占各层土壤总SOC含量的52.55%(林芝云杉)和51.87%(急尖长苞冷杉),而表层(0~20 cm)SMBC含量占各层土壤总SMBC含量的64.24%(林芝云杉)和65.48%(急尖长苞冷杉);2个林型8-9月份土壤呼吸值最高,12月份最低,土壤呼吸最大值分别为6.27μmol/(m2·s)(急尖长苞冷杉)、4.91μmol/(m2·s)(林芝云杉)。指数回归方程可以很好地描述土壤呼吸速率与土壤温度之间的相关关系,除了急尖长苞冷杉林的枯枝落叶呼吸外,其他的呼吸组分及林芝云杉各呼吸组分速率均与土壤水分含量呈显著的一元线性关系(P<0.05)。2种林分的微生物呼吸占总呼吸量的比例最高,其次为枯枝落叶呼吸和根系呼吸。微生物呼吸在夏秋季所占比例较高,根系呼吸在春夏季所占比例较高,枯枝落叶呼吸则在春末夏初所占比例较高。
Sub-alpine dark coniferous forest vegetation in Tibet is an important ecological barrier in China and plays an important role in the carbon balance of the global terrestrial ecosystem. In this study, the two most typical natural dark coniferous forests of Sejila, Tibet: Abies georgei var.smithii and Picea likiangensis var. Linzhiensis were selected as the study objects and their soil organic Carbon content and microbial biomass carbon, and the soil respiration and the rate of each respiratory component were monitored dynamically. The results showed that the SOC content and SMBC content of the two vegetation types all had obvious surface aggregation. The surface layer (0-20 cm) SOC content accounted for 52.55% (spruce) and 51.87% (spruce) of total soil, while SMBC content of surface layer (0-20 cm) accounted for 64.24% of total soil SMBC content (Picea crassifolia) and 65.48% (Abies georgei), respectively. The soil respiration of the two forest types from August to September was the highest, lowest in December, and the maximum soil respiration was 6.27μmol / (m2 · s) Buds fir), 4.91μmol / (m2 · s) (spruce). The exponential regression equation can well describe the correlation between soil respiration rate and soil temperature. Except for the litter respiration of Abies faxatum forests, the respiration rates of other respiration components and spruce Soil moisture content showed a significant linear relationship (P <0.05). The proportion of microbial respiration to total respiration in the two stands was the highest, followed by litter respiration and root respiration. Microbial respiration in summer and autumn accounted for a higher proportion of the root respiration in spring and summer accounted for a higher proportion of litter respiration in the late spring and early summer accounted for a higher proportion.