三江平原小叶章枯落物分解及硫素释放动态

利用分解袋法研究了三江平原小叶章湿地枯落物在两个生长季的分解动态和硫素释放规律。结果表明：小叶章枯落物的分解模式为快一慢交替的变化模式。残留率随着时间逐渐降低，分解480d后小叶章典型草甸枯落物的残留率为70．87％，小叶章沼泽化草甸枯落物的残留率为66．28％，其二者相应的分解速率分别为0．0006117d^-1和0．0006745d^-1，二者的质量损失没有显著差异。二者枯落物中硫素的浓度在分解过程中均呈波动变化，并和干物质残留率存在线性关系，硫素释放模式为：淋溶一固持一释放，C：S是决定其释放模式的主要因素，当C：S降至908．59时小叶章典型草甸枯落物中硫素开始迅速释放，而小叶章沼泽化草甸枯落物硫素开始释放的C：S是1451．41。

Decomposition of Deyeuxia angustifolia Litter in Sanjiang Plain and Dynamics of Sulfur Release

Using litterbags, the dynamics of decomposition and sulfur release from Deyeuxia angustifolia litter in Sanjiang Plain were studied during two growth seasons, the results showed that the decomposition mode of Deyeuxia angustifolia litter were the alternate changes of fast-slow, the mass remaining rate were both declined with the time and they were 70. 87% and 66.28% respectively in the typical meadow Deyeuxiaangustifolia and marsh meadow Deyeuxiaangustifolia after decomposing for 480 days, and its decomposition rates were 0. 0006117d^-1 and 0. 0006745d^-1 respectively, and no obvious difference in mass lost for both litters were observed. The concentrations of sulfur in the litter of typical meadow Deyeuxia angustifolia and marsh meadow Deyeuxiaangustifolia were both undulately changed during the litter decomposition and had linear relationship with dry matter remaining. The release patterns of sulfur form the litter of the typical meadow Deyeuxia angustifolia and marsh meadow Deyeuxia angustifolia were both leaching-immobilization-release, which were governed by the ratioes of C to S in the remaining matter of litter and sulfur from litter of typical meadow Deyeuxia angustifolia began releasing quickly when the ratio of C to S declined to 908.59, while the sulfur from litter of marsh meadow Deyeuxia angustifolia began releasing quickly,when the ratio of C to S were 1451.41.