Abstract.During 1986 erosion on soil mulched with 6 t ha‐1of straw was compared with that on soil maintained bare by herbicides in a mature apple orchard. The orchard was on well‐drained soil with a sandy loam top on a slope of 2°. Erosion was greatest in the alleys between the trees, where traffic had compacted and smoothed the soil. The mean annual soil loss on bare ground in the alleys was 0.45 t ha‐1; straw mulch reduced this by 85%. Erosion was worst between July and October, when rainfall>10 mm h‐1was most frequent. However, differences in soil moisture and resistance to infiltration may have also contributed to differences in erosion throughout