芦苇沼泽和羊草草甸土壤呼吸动态研究

Research on dynamics of soil respiration in phragmites australis marsh and leymus chinensis meadow

土壤呼吸是陆地生态系统中土壤碳库和大气碳库之间进行碳交换的关键途径。以莫莫格湿地内芦苇沼泽和羊草草甸为样地,在2014年5月～2015年5月间,利用ACE土壤碳通量自动测定仪对土壤呼吸的日变化和季节动态进行了监测。结果表明,羊草草甸土壤呼吸速率的日变化呈现较明显的单峰曲线,芦苇沼泽的日变化呈现一定的波动性。二者土壤呼吸速率的最高值分别出现在2014年7月和2014年5月14：00前后;最低值分别出现在2014年12月和2015年2月23：00前后。生长季是该两种群落土壤中CO_2主要释放时期。影响因素中,土壤5cm温度和表层土壤含水量对土壤呼吸影响显著,分别可以解释羊草草甸和芦苇沼泽土壤呼吸作用的72%和68%。

As a significant part of the world carbon cycle,soil respiration plays a key role in the carbon exchanges between terrestrial ecosystems and the atmosphere.Two sample plots were chosen in leymus chinensis meadow and phragmites communis marsh respectively in Momoge Wetland,of which the seasonal and diel variations of Rs were measured by ACE automatic soil CO_2 exchange system from May 2014 to May 2015.Results showed that the changing pattern of Rsin leymus chinensis meadow for diel variation was almost a unimodal curve,while that in phragmites australis marsh was a multimodal curve.The maxima of soil respiration rates in leymus chinensis meadow and phragmites australis marsh were at about 14：00in July 2014 and May 2014,respectively.The minima of soil respiration rates were at about 23：00in December 2014 and in February 2015.Most of the soil CO_2 released during plants growing season in the two plots.Rswas significantly affected by the two factors of soil temperature at 5cm depth and water content in soil surface,which can influence 72%and 68% of variations in Rsof the leymus chinensis meadow and phragmites australis marsh respectively.