Chalkland soil formation and erosion on the Yorkshire Wolds, northern England

Abstract

Investigations at four sites on the Yorkshire Wolds have provided evidence for the derivation of soil material, nature of pedogenic processes and history of soil erosion. Soil material overlying the chalk bedrock is thought to contain a Late Devensian aeolian clay component in addition to the previously recognised aeolian silt and fine sand. The thickness of this material, controlled largely by relief, is primarily responsible for soil type differentiation. Interfluve areas support mainly brown calcareous earths (Lithic Eutrochrepts), shallower rendzinas (Lithic Rendolls) occur on the upper and mid-slopes of valley sides, and thicker colluvial brown calcareous earths (Rendollic Eutrochrepts) on footslopes and valley floors. Holocene weathering has resulted in chalk dissolution, iron and aluminium release and clay mineral transformation. Biological processes have produced well-mixed surface mineral-organic horizons, and translocation has involved basic cations, CaCO 3 and clay. There is evidence that soil erosion has occurred during the past 2000–3000 years, probably largely as a result of cultivation. Soil removal from a gentle, upper valley slope over this period has been approximately 375 kg m −2, equivalent to a loss of around 0.1–0.2 kg m −2 year −1, and has resulted in a change in soil type from brown calcareous earth to rendzina.