摘要
通 过在０ ．１７ ｋ ｍ ２ 面积 的小流域 １９８ 个 点、５２５ 个样 品 表层 土壤 中１３７ Ｃｓ 含 量 的分 析，研究 结果表明 ：①不同 地貌部位１３７ Ｃｓ 含量有 明显 分异 ，为１３７ Ｃｓ 法定 量研 究 土壤 侵 蚀与 沉积 提供了 科学依据 ；②小流 域泥沙主 要来源 于沟谷地 ，占流域 总产沙量 的７２ ．４ ％ ；③１３７ Ｃｓ 技术测 定的是 净土壤侵 蚀量，可 提供更为 真实的 侵蚀、产 沙及 沉积 信息， 虽计 算侵 蚀 量和 沉 积量 有待 完善， 但可较准 确地表达 相对侵 蚀量的变 化 与分 布趋 势， 这是１３７ Ｃｓ 技 术与 其 他方 法 相比 较显 著的特 点。
The amount of 137 Cs of the 525 soil samples were analyzed on different landform units in a small watershed.The results showed:(1)The variations of the amount of 137 Cs on the different landform units are obvious ,which offered the scientific foundation to study soil erosion.(2)In addition, the sediment came from the gully slope mainly, occupying 72.4% of the total amount sediment in the watershed.(3)The 137 Cs technique measured net soil loss at each site rather than the total soil loss estimated by other methods, and thus provided better information on true erosion rates and sediment delivery. This is the special characteristics of 137 Cs technique, although the 137 Cs method is not perfect enough to estimate precisely erosion and deposition amount, the variation and trend of the relative erosion amounts could be described more accurately.
基金
国家自然科学基金
