不同森林群落类型土壤蚯蚓数量和生物量的时空分布特征

【目的】明确不同森林群落类型对其土壤蚯蚓数量(密度)及生物量时空动态的影响。【方法】采用电击法研究了云南省昆明市3种森林群落类型的土壤蚯蚓密度与生物量的时空分布规律,用相关分析与方差分析方法,分析3种森林类型的样地土壤理化环境与蚯蚓密度及生物量变化的相关性。【结果】①森林群落类型显著影响蚯蚓密度(P=0.001)和生物量(P=0.006),各森林群落类型下土壤蚯蚓密度与生物量的大小顺序分别为:云南松群落>桉树群落>疏林群落、云南松群落>疏林群落>桉树群落。②蚯蚓密度和生物量时间变化总体上表现为:9月>10月>11月。垂直分布表现为:桉树群落与云南松群落蚯蚓及生物量主要分布在≥5～10 cm土层,而疏林群落主要集中于0～5 cm土层。③桉树群落土壤温度、pH及水解氮与蚯蚓密度和生物量呈显著正相关关系(P<0.05); 土壤含水量、有机质、全氮等与蚯蚓密度及生物量变化趋势基本一致,但它们与蚯蚓密度及生物量的相关性未达到显著水平; 云南松群落和疏林群落下蚯蚓密度及生物量与土壤温度显著相关(P<0.05),而与土壤含水量、有机质、全氮、水解氮等相关性不显著。【结论】3种森林群落类型中土壤蚯蚓密度及生物量的时空分布具有显著的差异性,这种差异性与样地土壤理化环境(温度、水分、pH、土壤氮等)的变化密切相关。

Spatio-temporal distribution characteristics of soil earthworm number and biomass under different forest communities

Objective] It is important to understand the effects of different forest types on the spatiotemporal dynamics of earthworm number and biomass in soil.Methods] The electric shock method was used to explore the spatiotemporal patterns of earthworm number (density) and biomass in three forest types in Kunming City,Yunnan Province.The correlations between the soil physical and chemical environment and soil earthworm number (density) and biomass changes were assessed by the analyses of correlation and variance among the three forest communities.Results] Forest community type had significant effects on earthworm number (P =0.001) and biomass (P =0.006).The order of soil earthworm number was Pinus yunnanensis community ＞ Eucalyptus maideni community＞open forest community,and that of earthworm biomass was P.yunnanensis community＞open forest community＞E,maideni community.The temporal variation of both measures were ranked in the order September＞November＞October.The earthworm number and biomass in the E.maideni community and the P.yunnanensis community were mainly distributed in the ≥ 5-10 cm soil layer,and those in open forest were mainly concentrated in the 0-5 cm soil layer.Soil physicochemical properties had diverse effects on earthworm number and biomass.Soil pH,soil temperature and nitrogen hydrolysis showed positive correlations with earthworm number and biomass in the E.maideni community (P＜0.05).However,while soil water content,soil organic matter and total nitrogen had similar spatiotemporal changes as the variation of earthworm number and biomass,they were not significantly correlated with the earthworm number and biomass.In the P.yunnanensis community and open forest community,earthworm number and biomass were significantly correlated with soil temperature (P＜0.05),but soil water content,soil organic matter,total nitrogen,soil hydrolyzable nitrogen had no significant correlations with earthworm number and biomass.Conclusion] There were significant differences in the spatiotemporal distributions of soil earthworm number and biomass under the three forest types,and the differences were closely related to the changes in soil physicochemical properties (e.g.,soil temperature,soil water content,pH and soil nitrogen content).