Potentilla fruticosascrub, Kobresia humilismeadow and Kobresia tibeticameadow are widely distributed on the Qinghai-Tibet Plateau. During the grass exuberance period from 3 July to 4 September, based on close chamber-...Potentilla fruticosascrub, Kobresia humilismeadow and Kobresia tibeticameadow are widely distributed on the Qinghai-Tibet Plateau. During the grass exuberance period from 3 July to 4 September, based on close chamber-GC method, a study on CO 2 emissions from different treatments was conducted in these meadows at Haibei research station, CAS. Results indicated that mean CO 2 emission rates from various treatments were 672.09±152.37 mgm -2 h -1 for FC (grass treatment); 425.41±191.99 mgm -2 h -1 for FJ (grass exclusion treatment); 280.36±174.83 mgm -2 h -1 for FL (grass and roots exclusion treatment); 838.95±237.02 mgm -2 h -1 for GG (scrub+grass treatment); 528.48±205.67 mgm -2 h -1 for GC (grass treatment); 268.97±99.72 mgm -2 h -1 for GL (grass and roots exclusion treatment); and 659.20±94.83 mgm -2 h -1 for LC (grass treatment), respectively (FC, FJ, FL, GG, GC, GL, LC were the Chinese abbreviation for various treatments). Furthermore, Kobresia humilismeadow, Potentilla fruticosascrub meadow and Kobresia tibeticameadow differed greatly in average CO 2 emission rate of soil-plant system, in the order of GG>FC>LC>GC. Moreover, in Kobresia humilismeadow, heterotrophic and autotrophic respiration accounted for 42% and 58% of the total respiration of soil-plant system respectively, whereas, in Potentilla fruticosascrub meadow, heterotrophic and autotrophic respiration accounted for 32% and 68% of total system respiration from GG; 49% and 51% from GC. In addition, root respiration from Kobresia humilismeadow approximated 145 mgCO 2 m -2 h -1 , contributed 34% to soil respiration. During the experiment period, Kobresia humilismeadow and Potentilla fruticosascrub meadow had a net carbon fixation of 111.11 gm -2 and 243.89 gm -2 , respectively. Results also showed that soil temperature was the main factor which influenced CO 2 emission from alpine meadow ecosystem, significant correlations were found between soil temperature at 5 cm depth and CO 2 emission from GG, GC, FC and FJ treatments. In addition, soil moisture may be the inhibitory factor of CO 2 emission from Kobresia tibeticameadow, and more detailed analyses should be done in further research.展开更多
文摘Potentilla fruticosascrub, Kobresia humilismeadow and Kobresia tibeticameadow are widely distributed on the Qinghai-Tibet Plateau. During the grass exuberance period from 3 July to 4 September, based on close chamber-GC method, a study on CO 2 emissions from different treatments was conducted in these meadows at Haibei research station, CAS. Results indicated that mean CO 2 emission rates from various treatments were 672.09±152.37 mgm -2 h -1 for FC (grass treatment); 425.41±191.99 mgm -2 h -1 for FJ (grass exclusion treatment); 280.36±174.83 mgm -2 h -1 for FL (grass and roots exclusion treatment); 838.95±237.02 mgm -2 h -1 for GG (scrub+grass treatment); 528.48±205.67 mgm -2 h -1 for GC (grass treatment); 268.97±99.72 mgm -2 h -1 for GL (grass and roots exclusion treatment); and 659.20±94.83 mgm -2 h -1 for LC (grass treatment), respectively (FC, FJ, FL, GG, GC, GL, LC were the Chinese abbreviation for various treatments). Furthermore, Kobresia humilismeadow, Potentilla fruticosascrub meadow and Kobresia tibeticameadow differed greatly in average CO 2 emission rate of soil-plant system, in the order of GG>FC>LC>GC. Moreover, in Kobresia humilismeadow, heterotrophic and autotrophic respiration accounted for 42% and 58% of the total respiration of soil-plant system respectively, whereas, in Potentilla fruticosascrub meadow, heterotrophic and autotrophic respiration accounted for 32% and 68% of total system respiration from GG; 49% and 51% from GC. In addition, root respiration from Kobresia humilismeadow approximated 145 mgCO 2 m -2 h -1 , contributed 34% to soil respiration. During the experiment period, Kobresia humilismeadow and Potentilla fruticosascrub meadow had a net carbon fixation of 111.11 gm -2 and 243.89 gm -2 , respectively. Results also showed that soil temperature was the main factor which influenced CO 2 emission from alpine meadow ecosystem, significant correlations were found between soil temperature at 5 cm depth and CO 2 emission from GG, GC, FC and FJ treatments. In addition, soil moisture may be the inhibitory factor of CO 2 emission from Kobresia tibeticameadow, and more detailed analyses should be done in further research.
