破碎程度对凋落物分解过程中CO2释放的影响

Influence of Fragmentation Degree on CO Release by Leaf Litter During Its Decomposition

以黑龙江省齐齐哈尔市4种绿地植被凋落物为研究对象,进行不同程度破碎(<0.149 mm、0.149~1.000 mm、1.000~2.000 mm、2.000~10.000 mm)处理后,采用室内恒温培养、碱液吸收法测定1~160 d间4种植被凋落物4个破碎程度下CO2释放速率的变化,以期了解破碎程度对凋落物分解过程的影响。结果表明:4种植被凋落物总体表现为随破碎程度增加,CO2释放速率加快。不同破碎处理对阔叶凋落物CO2累积释放量影响显著(P<0.05),对针叶凋落物CO2累积释放量影响不显著(P>0.05)。不同破碎处理与阔叶凋落物在1~20 d间相关性显著(P<0.05)。凋落物在2~20 d间CO2释放速率与初始凋落物质量(理化性质)之间相关性显著(P<0.05)。上述结果表明破碎处理对阔叶凋落物CO2释放过程影响较大,破碎会导致其CO2释放速率增加,并随破碎程度加大而增高,但对针叶凋落物CO2释放过程影响仅在试验初期较明显;1.000 mm以下破碎处理凋落物CO2释放速率稳定性高,为今后室内试验提供参考依据。

To understand the influence of fragmentation degree on the leaf litter decomposition process,leaf litters from four kinds of greenbelt vegetationin Qiqihar city,Heilongjiang Province were broken to four different degrees(<0.149 mm,0.149-1.000 mm,1.000-2.000 mm,2.000-10.000 mm),respectively,to be used as research objects.Under the condition of indoor thermostatic culture,the variation in the CO2 release rate of the broken leaf litters in the period of 1-160 days was measured using the alkali absorption method.The results showed that,the CO2 release rate of leaf litters from four kinds of vegetation generally increases with an increasing fragmentation degree;the influence of fragmentation degree on the broad-leaved litter cumulative release of CO2 was significant(P<0.05),while that on the needle-leaved litter cumulative release of CO2 was not significant(P>0.05);the CO2 release rate of broad-leaved litter in the period of 1-20 days was strongly correlated with the fragmentation degree(P<0.05),and the CO2 release rate of leaf litters from the four kinds of vegetation in the period of 2-20 days was all strongly correlated with the initial litter quality(physicochemical property)(P<0.05).It can be concluded from the above results that the breakage treatment can significantly influence the whole CO2 release process of broad-leaved litter,leading to a higher rate of CO2 release,which increases with the fragmentation degree,but only has significant influence on the initial-stage CO2 release of needle-leaved litter;litters that were broken to the below1.000 mm degree can end up releasing CO2 at a highly steady rate,which can be of reference value to the indoor laboratory tests in the future.