关键词: 土壤风蚀, 共和盆地, ¹³⁷Cs含量, ¹³⁷Cs剖面分布

Abstract: Wind erosion is the first step to sandy desertification,and it is obvious that the accurate measurement and estimation of wind erosion rate is urgent and essential.Owing to the complexity,randomness and boundlessness of the processes,it is difficult to measure or estimate the wind erosion rate precisely at present.Current methods that include field observation,wind tunnel tests and wind erosion model have some limitations in their practicability,cost and accuracy.The world-fallout of ¹³⁷Cs associated with the nuclear weapons tests during 1950s and 1960s has provided a valuable man-made tracer for studing soil erosion and sediment delivery.Since its first introduction in the 1970s,¹³⁷Cs technique has received wide application in water erosion research,leading to profound accomplishments.But it was not applied to wind erosion until the 1990s and still remains insufficiency in this respect.Taking the Gonghe Basin in Qinghai Province as the study area,the paper attempts to introduce the ¹³⁷Cs method to study soil wind erosion.Through specific sampling strategy and methods,large number of ¹³⁷Cs samples with different soil types or land uses are gathered and analyzed.From those ¹³⁷Cs data,some ¹³⁷Cs distribution characteristics over the whole area are clarified.The 0~30 cm ¹³⁷Cs activity of different land types is found to be in the order of woodland > playa > cold grassland > dry farmland≈dry grassland > fixed dune > desertified grassland > shifted dune > eroded land,while the ¹³⁷Cs inventory of different land types is in the order of playa > woodland > shifting dune > cold grassland > dry farmland≈dry grassland > fixed dune > desertified grassland > eroded land.The ¹³⁷Cs distribution in the soil profile can be divided into four types of normal profile,aggrading profile,eroding profile and disturbed profile.The cold grassland that maintained the relatively perfect normal profile of original ¹³⁷Cs fallout can be regarded as ideal sampling site of ¹³⁷Cs reference.

Key words: wind erosion, Gonghe Basin, ¹³⁷Cs activity, ¹³⁷Cs depth distribution