<正>讨论了下蜀森林生态定位站中杉木林、火炬松林和天然次生栓皮栎林三个径流场林地土壤的母质来源、基本性状和分类意见。三处剖面均为土状沉积物形成的母质，根据相关地质资料以及土壤矿物颗粒分析和矿质化学分析后确认，其母质均为下蜀组（Ｑ３ｘ） 黄土状沉积物。三个土壤剖面均有一定的漂洗和淀积粘化现象，但都不足以定义成漂白层或粘盘层。栎林中凋落物分解状况和土壤腐殖化过程良好，土壤养分浓度（ 如土壤有机质和速效氮、磷、钾）均高于火炬松林和杉木林；淋溶作用明显、交换性盐基离子较少、而交换性酸较高。火炬松林和杉木林中凋落呈未分解或轻度分解的特征，粗腐殖化特征明显，而淋溶稍弱、交换性盐基离子较高、交换性酸较低。同时，根据现行中国土壤分类系统、第二次全国土壤普查分类系统和中国土壤系统分类首次方案对三处林地的土壤进行了分类。

Soil parent material origins, properties and classification were discussed on the three principal runoff plots in the forests of Chinese fir, loblolly pine, and oak for long-term observations, which were not fully characterized before. The parent materials were defined as loess-like sediments(Q 3x) according to the particle and chemical analysis and the geological records. Bleaching and characterization were morphologically apparent, but not well developed as to be defined as bleached or claying horizons. Soil under oaks, compared with soils under Chinese firs and loblolly pines, showed higher nutrient concentrations (N, P and K) and humification, lower base saturation percentages and soil pH. The soils were placed in Yellow-cinnamon subgroup of Yellow-brown soil group (Soil Classification of China, 1978), Yellow-cinnamon subgroup of Yellow-cinnamon soil group (Soil Classification of China for the Second National Soil Survey, 1998) and Argillic yellow-brown soil subgroup of Yellow-brown soil group (Chinese Soil Taxonomic Classification, 1st proposal, 1991).