摘要
采用同化箱法测定了青海省南部果洛藏族自治州玛沁县不同退化程度天然草地及不同建植年限人工草地植物群落光合作用、暗呼吸及CO2净交换量。结果表明,天然草地植物群落光合作用过程CO2吸收量与暗呼吸作用CO2释放量的变化趋势为:中度退化草地<重度退化<极度退化<未退化草地;未退化、中度及重度退化高寒草地植物群落净吸收CO2,而极度退化高寒草地植物群落净释放CO2。对"黑土滩"型极度退化草地进行人工恢复后,植物群落通过光合作用吸收CO2量增加;2000和2004年建植的垂穗披碱草(Ely-musnutans)单播人工草地植物群落净吸收CO2量分别为1.33和2.3μmolCO2.m-2.s-1,大于2002和2005年混播人工草地;对单播或混播人工草地而言,随着建植年限增加,草地出现一定程度的退化现象,CO2净吸收量也逐渐下降。从青藏高原碳管理的角度,中、重度退化草地要防止退化为"黑土滩"型极度退化草地,使其恢复到未退化程度;极度退化草地要及时进行人工恢复,有效增加碳的吸收量。
By the method of carbon assimilation chamber,we measured the photosynthetic rate,dark respiration rate,and net carbon dioxide (CO2) exchange of plant communities on the natural grasslands at different degradation levels and the artificial grasslands having been planted for different years in the Maqin County of Qinghai Province. On the natural grasslands at different degradation levels,the photosynthetic rate and dark respiration rate of plant communities had a variation trend of moderately degraded grassland heavily degraded grassland extremely degraded grassland non-degraded grassland. A certain amount of CO2 was absorbed by the plant communities on the non-degraded,moderately degraded,and heavily degraded grasslands,while 1.20 μmol CO2·m-2·s-1 was released from the extremely degraded grassland. After the artificial restoration of the extremely degraded grassland,the CO2 release reduced. The mono-cultured Elymus nutans grassland established in 2000 and 2004 absorbed much more CO2 than did the mixed cultivated grassland established in 2002 and 2005. With the increasing established year of mono-cultured and mixed cultivated grasslands,the net CO2 absorption by the plant communities decreased. From the viewpoint of carbon management in Qinghai-Tibet Plateau,it was suggested that the moderately and heavily degraded alpine grasslands should be prevented from being further degraded,and the extremely degraded alpine grassland should be artificially restored in time to effectively increase the CO2 absorption by plant community.
出处
《生态学杂志》
CAS
CSCD
北大核心
2010年第10期1944-1949,共6页
Chinese Journal of Ecology
基金
国家自然科学基金资助项目(30870466和50939001)
关键词
三江源
光合作用
暗呼吸
二氧化碳净交换量
headwater area of Three Rivers
photosynthesis
dark respiration
net carbon dioxide exchange.