Abstract:Soil loss tolerance(T-value) is an important value to judge gradation of soil erosion and efficiency of its control countermeasures.In this study,soil formation rates(SR) of the purple soils(a Regosols) in the hilly area of Sichuan,China were determined by Barth equation(SR-estimated) and field measurements(SR-measured) with the three treatments of soil types(J1s,J3s,and J3p soils),vegetations(wheat-maize,loquat tree,and ryegrass),and soil depths(10,20,40,and 60 cm).SR-estimated values are generally smaller than SR-measured values.SR-measured values vary significantly among the treatments.Based on the SR-measured values,the T-value was determined as 800 t/(km2·a) for J3s purple soil,and 1 200 t/(km2·a) for J1s and J2s soils in the studied region.