Abstract:The limiting factors of soil nutrients were identified by systematic application of indicator plant (grain sorghum) and diagnostic soil analyses (soil adsorption trial and pot experiment) in three different dry croplands in Sangzhi County, Zhangjiajie City, Hunan Province. The results showed that the available Ca, Fe, Mn and B were sufficient in the soils, which having higher adsorption capacity for P than other nutrients. Compared with that of OPT treatment, biomass of grain sorghum plant grown under N-, P-, and S-lacked treatments decreased averagely by 79%, 41% and 33% respectively, it suggested N, P and S are the first, second and third nutrient limiting factors, respectively.