重庆市四面山典型林分土壤饱和导水率研究

Saturated Hydraulic Conductivity in Soils Under Typical Forests in Simian Mountains of Chongqing City

采用恒定水头法测定了重庆市四面山地区典型人工林和天然次生林剖面土壤饱和导水率(Ks),并运用多元回归和通径分析方法探讨了其与土壤物理因子和有机质的相关性。结果表明,土壤饱和导水率从表层到深层呈现出负指数形式的递减规律。各林分对饱和导水率均有显著提高,由高到低的顺序为:天然针阔混交林>天然阔叶林、楠竹林、针叶林>人工阔叶林、混交林、针叶林>荒地。土壤黏粒、容重、非毛管孔隙度和大于0.25 mm水稳性团聚体含量是影响该地区饱和导水率的主要因子。各林分对土壤有机质含量均有提高作用,有机质含量与饱和导水率符合二次曲线的关系。在植被经营过程中,建议营造针阔复层混交类型的树种配置模式。

On the soil profiles under typical planted and natural secondary forests in Simian Mountains of Chongqing City,soil saturated hydraulic conductivity（Ks） was measured by the constant-hydraulic head method,and the correlations between Ks and soil physical features and organic matter contents were established using multivariate regression and path analysis.The results show that,the values of Ks decreased negatively exponentially with increasing soil depths.Comparing to the control,Ks was significantly improved in all the forests,with effects in a descending order as： natural secondary Conifer×Broadleaf forest land natural secondary Broadleaf forest,Phyllostachys pubescens forest,Conifer forest landBroadleaf plantation,Conifer×Broadleaf plantation,Conifer plantation land wasteland.Soil clay content,bulk density,non-capillary porosity and 0.25 mm aggregate content were the key factors affecting Ks.The Forests encouraged effectively the accumulation of organic matters in the soils.The relationship between Ks and organic matter was well described with quadratic equations.Mixed mode of Conifer×Broadleaf with multiple layers is recommended in forest plantation and management.