干旱区生态环境知识资源中心

The world fallout of caesium-137 (Cs-137) associated with nuclear weapons testing during the 1950s and 1960s has provided a valuable man-made tracer for studies of soil erosion and sediment delivery. But relatively few researchers have used it to estimate wind erosion. In this paper, the Cs-137 technique is introduced into the study of wind erosion and its modern processes in the Qinghai-Tibet Plateau. Two Cs-137 reference inventories of 982.11 and 2376.04 Bq m(-2) was established preliminarily, which distribute in the south and mid-north parts of the study area respectively. By analysing the patterns of Cs-137 depth profiles from sampling sites, the aeolian processes of erosion and deposition along nearly 40 years has been revealed, i.e. the shrub coppice dunes(S1) and semi-fixed dunefields (S3) had experienced the alternation of erosion and deposition, while the grasslands (S4, S6 and S7) and dry farmlands (S5) suffered erosion only. By using the Cs-137 model, the average wind erosion rates for shrub coppice dune (S1), semi-fixed dunefields (S3), dry farmlands (S5) and grasslands (S4, S6 and S7) were estimated to be 84.14, 69.43, 30.68 and 21.84 t ha(-1) a(-1) respectively, and for the whole Plateau, averaging 47.59 ha(-1) a(-1) which can be regarded as the medium erosion standard. These results derived from Cs-137 for the first time have significant implications for the further research of wind erosion and desertification control in the Qinghai-Tibet Plateau, (C) 2001 Academic Press.