The Zhuanyaogou River watershed is located in the central-western part of Hequ County,Shanxi Province,i.e.,39°11′06″～39°13′47″N,111°12′03″～111°19′28″E,it
is a first-grade tributary of the Yellow River,its catchment area is 28.7 km 2,and its gully density is as high as 6.2 km/km 2. The climate here belongs to the warm-temperate continental monsoon climate,the annual air temperature is 8.8℃,and the annual precipitation and evaporation are 447.5 mm and 1 913.7 mm respectively. The natural vegetation is sparse and the soil erosion is serious in the region. In this paper,the spatial variability and distribution characteristics of soil carbonate carbon in the
watershed are researched by analyzing the soil samples sampled from 62 sampling sites at 9 soil layers in the watershed and by using geostatistical method. The results show that the spatial variability of
carbonate carbon content in soil is in a mid-intensity except that in the soil layer of 80～100 cm in depth,and it is caused by the spatial self-correlative factors. The carbonate carbon content in soil is the highest on the top of hills and the lowest in the gullies in the same soil layer. Moreover,the change of the carbonate carbon content in soil at these two geographical locations is smaller than that on the slopes of hills. The illuviation depth of carbonate carbon in soil is different from the different geographical locations. Taking the illuviation layer as the boundary,the carbonate carbon content is lower in topsoil than that under it in the gullies;it is similar in topsoil and under it on the slopes;and it is higher in topsoil than that under it on the top of hills.