海南岛滨海台地5种典型林分类型土壤理化特性研究

Soil physical and chemical properties of five subtropical forests in Wenchang coastal platform, Hainan

以海南岛滨海台地5种典型林分类型为研究对象，研究不同森林类型0～100cm土层土壤理化性质。结果表明，次生林土壤容重相对最大，相思林土壤容重相对最小，椰树林土层间变异系数最大，木麻黄林最小。5种不同森林类型表层土壤（0～10cm，10～20cm）随着土壤深度的变化，土壤总孔隙度和非毛管孔隙度呈增大趋势，其他层次土壤总孔隙度变化和非毛管孔隙度呈不规律性变化。随着土壤深度的增加，土壤含水率呈递增状态，不同森林类型间土壤总孔隙度、土壤含水率差异性显著。5种不同森林类型土壤pH都呈酸性或微酸性，木麻黄林与次生林、桉树林、相思林pH值差异性显著。5种森林土壤全N含量在土壤剖面中具有明显的垂直分布性，随着土壤深度的增加呈降低趋势，不同森林类型间全N、全K含量差异性显著，全P含量差异性不显著。同一森林类型0～10cm土壤全N与其他层次显著性差异，说明滨海沙土表层更利于N素循环。

To understand the physical and chemical properties of soil in 0-100 cm layer in different forest types, this paper studied five typical forest types in the coastal platform of Hainan Island. The results showed that soil bulk density of secondary forest was the highest, while Acacia auriculaeformis forest was the lowest. The variation coefficient of soil layer showed that the coconut forest was the largest, and Casuarina equisetifolia forest was the lowest. The total soil porosity and non-capillary porosity of five different forest types （0-10 cm, 10-20 cm） increased with the depth of soil, but in other layers, they were irregularity. The soil water content increased with the depth of soil, and the differences were significant in different forest types. The pH value in five different forest types was acidic or slightly acidic, the differences between Casuarina equisetifolia forest and secondary forest, Eucalyptus forest, Acacia anriculaeformis forest were significant. Soil total N content in soil profile had a clear vertical distribution, which decreased with the depth of soil. The differences of total N and K contents were significant, while the P content was not in different forest types. There was significant difference in soil total nitrogen between 0-10 cm and other layers in the same forest type, which indicated that the surface layer of seashore sand soil was more beneficial for N cycle.