黄土丘陵区小流域泥沙来源及其动态变化的^(137)Cs法研究  

A STUDY ON SOIL EROSION RATES AND SEDIMENT SOURCES USING CAESIUM-137 TECHNIQUE IN A SMALL DRAINAGE OF THE LOESS HILLS

作　　者：文安邦[1] 张信宝[2] 沃林DE 

机构地区：[1]中国科学院,水利部成都山地灾害与环境研究所,成都610041 [2]中国科学院西安黄土与第四纪地质国家重点实验室,西安710054 [3]爱克塞特大学地理系

出　　处：《地理学报》1998年第B12期124-133,共10页Acta Geographica Sinica

基　　金：国家"八五"重大项目.编号85-926-07-01-04

摘　　要：通过沟间地、沟谷地不同类型土地表层土壤和淤地坝坝库沉积泥沙的^(137)Cs含量的对比分析,陕西子长赵家沟小流域沟间地、沟谷地相对产沙量分别为24%和76%,侵蚀模数分别为6580t/km^2·a和21118t/km^2·a。1973年~1977年15次洪水坝库沉积泥沙的^(137)Cs含量变化表明,汛期初期洪水的沟间地相对产沙量一般较汛期后期洪水为低。The paper reports the results using Caesium-137 technique to investigate soil erosion rates and sediment sources and its changing of Zhaojia gully catchment in the rolling Loess Plateau re-gion of Zhichang County, Shaanxi province, China, where absence of direct measurements of the soils erosion rates and sediment source observation, the results of the paper derived from reservoir deposited and from Caesium-137 measurement.Soil samples were mainly collected from the cultivated slope land in the loess hills, steep gully area and the sediment deposited in sediment trap reservoirs, and the Caesium-137 refer-ence samples collected from a plain grassland, where no disturbance sine 1953,and same altitude as the study cultivated slope land.The references inventory of Caesium-137 in study region was 2 504 Bq/mz, and the average Caesium-137 content of the rolling cultivated slope land and the steep cultivated slope land were 1 248- 2 Bq/m2 and 443. 1 Bq/m2 respectively. Based on measurement of the Caesium-137 con-tent of these soil samples, the estimated net erosion rates on cultivated land occupying the gen-tle crest slopes and steeper lower slopes of the rolling plateau and the steep gully slopes were 4 158 t/km' ?a, 8 584 t/km: ?a and 15 851 t/km2 ?a, respectively, and the rolling cultivated slope land and steep gully slope land were 6 580 t/km2 ?a and 21 118 t/kmz ?a respectivelyThe average content of surface samples collected from the rolling cultivated slope land, and the steep gully area were 3. 88 Bq/kq and 0. 02 Bq/kg respectively. The average content of thesediments deposited in dam 3 was 0. 91 Bq/kg. According to analysis of the Caesium-137 content of surface soil samples from the rolling cultivated slope land and gully slope land and the sedi-ment deposited in sediment trap reservoirs, the relative contribution of sediment from the rolling Plateau and gully area were estimated to be 2\''/. and 76 JK respectively. Analysis of the sedi-ment deposited dating from 1973?977 in another sediment trap reservoir enable

关 键 词：产沙量 ^137Cs法 小流域 黄土丘陵区 泥沙来源 动态变化 谷地 洪水 水坝 侵蚀模数 

分 类 号：P641.2[天文地球—地质矿产勘探] S157[天文地球—地质学]