Biological influences on the morphology and micromorphology of selected Podzols (Spodosols) and Cambisols (Inceptisols) from the eastern United States and north-east Scotland

Biological activities greatly influence the formation of many soils, especi ally forest soils under cool humid climates. The objective of this study wa s to investigate the effects of vegetation and soil biota on the formation of selected soils. Field morphology, micromorphology, and carbon and organi c matter analysis were determined on six Podzols (Spodosols) and two Cambis ols (Inceptisols) from the eastern United States and north-east Scotland. H umification of plant material by soil fauna and fungi occurs in all organic horizons. Thick organic coatings are observed on soil peds and rock fragme nts from the El to the Bs horizon in a Haplic Podzol from Clingmans Dome Mt ., TN. Thin sections reveal large accumulations of root material in differe nt stages of decomposition in the spodic horizons of a Haplic Podzol from W hiteface Mt., NY. Organic carbon ranges from 5.4 to 8.5% in the spodic B ho rizons of the Whiteface Mt. Podzol. Earthworms and enchytraeids have a grea t effect on the structure of the surface and subsurface horizons in the Dys tric Cambisols from Huntly and Clashindarroch Forests, Scotland and a Cambi c Podzol from the Corrie Burn Basin, Scotland. Podzols from Speymouth Fores t, Scotland (Gleyic Podzol), Clingmans Dome Mt., and Whiteface Mt. have thi ck organic horizons. The Podzols from the Flatwoods in Georgia, the Pine Ba rrens in New Jersey, the Corrie Burn Basin, and the Cambisol from Huntly Fo rest have only A horizons at the surface. The Clashindarroch Forest soil ha s a very thin organic horizon. Warm and humid climates and sandy parent mat erial are responsible for thick E horizons and lack of thick organic horizo ns in the Flatwoods (Carbic Podzol) and Pine Barrens (Ferric Podzol) soils. Earthworms and enchytraeids thrive in the Corrie Burn Basin and Huntly For est soils due to the vegetation and the highly weathered basic parent mater ial. The site at Clashindarroch once carried oak, and then birch forest, bo th of which produce a mild litter and also encourage earthworm and enchytra eids. This fauna is responsible for much mixing of the topsoil. The present conifer vegetation will eventually produce a deep Litter and cause podzoli zation. (C) 1999 Elsevier Science B.V. All rights reserved.