不同生态类型蚯蚓对土壤团聚体有机碳质量分数的影响

Effects of Earthworms of Different Ecological Types on Organic Carbon Content in Soil Aggregates

为探讨不同生态类型蚯蚓及其交互作用对土壤团聚体有机碳质量分数的影响,以森林土和农田土为研究对象,接种2种不同生态类型的蚯蚓赤子爱胜蚓(Eisenia foetida)和威廉环毛蚓(Pheretima guillemi),设置5种不同处理,在室温黑暗环境下培养180 d后,分析不同生态类型蚯蚓对土壤水稳性团聚体结构及各粒级有机碳质量分数的影响。结果表明:接种赤子爱胜蚓增加了森林土粗大团聚体(d>2.000 mm)质量分数,接种威廉环毛蚓和两种蚯蚓共同作用降低了森林土粗大团聚体质量分数,3种不同的蚯蚓处理均降低了农田土的粗大团聚体质量分数;2种不同生态型蚯蚓均降低了森林土和农田土细大团聚体(0.250 mm<d≤2.000 mm)的质量分数;单独接种1种蚯蚓增加了森林土微团聚体(0.053 mm<d≤0.250 mm)质量分数;3种不同的蚯蚓处理均增加了森林土粉-黏团聚体(d≤0.053 mm)质量分数;森林土和农田土在不同处理下,各粒级团聚体有机碳质量分数由高到低均为细大团聚体、粗大团聚体、微团聚体、粉-黏团聚体;接种蚯蚓显著降低森林土壤中粗大团聚体和细大团聚体有机碳质量分数,单独接种威廉环毛蚓以及2种蚯蚓共同作用下对土壤有机碳质量分数的影响显著高于单独接种赤子爱胜蚓。因此,农、林生态系统中蚯蚓数量增加可能引起土壤有机碳质量分数的下降,在农、林生态系统中接种蚯蚓的经营活动应同时添加农林有机废弃物,以改善或增强蚯蚓调控土壤有机碳固持及稳定的潜能。

In order to explore the effects of different ecological types of earthworms and their interactions on the content of organic carbon in soil aggregates,forest soil and agricultural soil were inoculated with two different ecological types of earthworms:Eisenia foetida and Pheretima guillemi.Five different treatments were set up to analyze the effects of different ecological types of earthworms on the structure of soil water-stable aggregates and the content of organic carbon of different diameter classes after 180-d incubation under room temperature and darkness.The results showed that inoculation with E.foetida increased the content of coarse aggregates(d>2.000 mm)in forest soils,inoculation with P.guillemi and two earthworms together decreased the content of coarse aggregates in forest soils.All three different earthworm treatments decreased the content of coarse aggregates in agricultural soils.Two different ecotypes of earthworms decreased the content of fine aggregates(0.250 mm<d≤2.000 mm).Inoculation of one earthworm alone increased the content of micro aggregates(0.053 mm<d≤0.250 mm)in forest soils.All three different earthworm treatments increased the content of silty aggregates(d≤0.053 mm)in forest soils.From high to low,the organic carbon content of forest soil and agricultural soil aggregates showed as follows:fine aggregates,coarse aggregates,microaggregates,silty aggregates.Inoculation of earthworms significantly reduced the organic carbon content of coarse and fine aggregates inforest soils,and the effect of inoculation of P.guillemi alone and the combined effect of the two earthworms on the organic carbon content of soils was significantly higher than that of inoculation of E.foetida alone.Therefore,the increase in the number of earthworms in agricultural and forest ecosystems may lead to the decrease of soil organic carbon content,so the management activities of inoculating earthworms in agricultural and forest ecosystems should add agricultural and forestry organic residues at the same time to improve or enhance the function of earthworms in soil carbon sequestration.