AbstractThe Peak District of Derbyshire, England, is a moorland region of high and increasing soil-erosion potential. Samples from a variety of soils developed in the area were tested under simulated rainfall to assess their relative erodibility. Results of tests permitted estimates of annual soil-loss under specified conditions, which ranged from near zero to 160 tons/acre year. Using a threshold value of 11 tons/acre year, 58% of the soils were deemed liable to serious erosion. Behaviour of samples under simulated rainfall is described, and largely explained by variations in aggregation characteristics. Results of tests indicate that podzolic soils are more erodible than brown earths, woodland soils more erodible than grassland soils,“gritstone”soils more erodible than“limestone”soils, and B horizon soils more erodible than A horizon soils. On the basis of test results a general hypothesis explaining patterns of soil erodibility in the region is advanced.