凤阳山主要林分类型土壤团聚体及其稳定性研究

Study on the composition and stability of soil aggregates of the main forest stands in Fengyang Mountain,Zhejiang Province

【目的】探究凤阳山自然保护区的林地土壤团聚体组成及其影响因素,为恢复与保护土壤资源提供一定的理论依据。【方法】以浙江省凤阳山自然保护区内海拔1 300~1 400 m范围内主要林分类型(阔叶混交林、针阔混交林、杉木林、竹林)林地为对象,测定不同土层土壤基本理化性质和水稳定性团聚体粒径分布及其含量,分析土壤理化性质对土壤团聚体及其稳定性的影响。【结果】(1)4种林分土壤水稳定性大团聚体(WSA)(≥0. 250mm)含量均在90%以上。土壤水稳定性大团聚体含量及平均质量直径(MWD)和几何平均直径(GMD)均以杉木林的最大,竹林的最小。(2)通过非度量多维标度(NMDS)排序分析,阔叶混交林、针阔混交林和杉木林对≥2. 000 mm粒级土壤团聚体影响较大,竹林对≥0. 053~0. 106 mm粒级的土壤团聚体的影响较大。(3)土壤密度与土壤MWD及GMD之间均呈显著正相关,与土壤分形维数(D)呈显著负相关。非毛管孔隙度与土壤MWD及GMD之间均呈显著负相关,与土壤D呈显著负相关。【结论】林分类型较土层深度对土壤团聚体粒级组成及稳定性的影响更显著,土壤密度及非毛管孔隙度等土壤理化性质较土壤总孔隙度、毛管孔隙度及总有机碳含量等对土壤团聚体粒级组成及稳定性的影响更显著。

【Objective】To provide a theoretical basis for the restoration and protection of soil resources,we explored the composition and influencing factors of soil aggregates in Fengyang Mountain Nature Reserve.【Method】This study based on four forest types（ broad-leaved mixed forest,coniferous and broad-leaved mixed forest,fir forest,bamboo forest）within the range of 1 300-1 400 m above sea level in Fengyang Mountain Nature Reserve of Zhejiang Province,we determined the content of soil water stability aggregates and physical and chemical properties in different soil layers,and analyzed the effects of soil physical and chemical properties on the composition and stability of soil aggregates. 【Result】（1） The content of soil water-stable macroaggregates（ WSA）（ ≥0. 25 mm） in four forest types was above 90%; WSA content,geometric mean diameter（ GMD） and average mass diameter（ MWD） in bamboo forest were lower than those in other forests,and the highest values were observed in fir forest.（2） Along the non-metric multidimensional scale（ NMDS） axis 1,the effects of fir forest,coniferous and broad-leaved mixed forest,and broad-leaved mixed forest on the soil aggregates of ≥2 mm were obviously significant,while the effect of bamboo forest on the soil aggregates of ≥0. 053-0. 106 mm was significant.（3） Soil density showed a negative correlation with soil fractal dimension and a significant positive correlation with MWD and GMD. Soil non-capillary porosity content showed significant negative correlations with soil MWD and GMD and with soil fractal dimension. 【Conclusion】The effects of forest types on the particle size compo-sition and stability of soil aggregates were more significant than those of the soil layers,and the effects of soil density and non-capillary porosity on the particle size composition and stability of soil aggregates were more significant than those of the soil total porosity,capillary porosity and total organic carbon content.