Preliminary results of using Cs-137 to study wind erosion in the Qinghai-Tibet Plateau

The world fallout of caesium-137 (Cs-137) associated with nuclear weapons t esting during the 1950s and 1960s has provided a valuable man-made tracer f or studies of soil erosion and sediment delivery. But relatively few resear chers have used it to estimate wind erosion. In this paper, the Cs-137 tech nique 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 a nd 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 processe s of erosion and deposition along nearly 40 years has been revealed, i.e. t he shrub coppice dunes(S1) and semi-fixed dunefields (S3) had experienced t he 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 du nefields (S3), dry farmlands (S5) and grasslands (S4, S6 and S7) were estim ated to be 84.14, 69.43, 30.68 and 21.84 t ha(-1) a(-1) respectively, and f or 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 fir st time have significant implications for the further research of wind eros ion and desertification control in the Qinghai-Tibet Plateau, (C) 2001 Acad emic Press.