MINERAL MAGNETIC-PROPERTIES OF ACID GLEYED SOILS UNDER OAK AND CORSICAN PINE

A comparison is made of the magnetic properties of acid gleyed soils u nder two woodland stands, oak (Quercus robur) and Corsican Pine (Pinus laricio). Twenty-five soil profiles under each type were sampled and analysed in three layers within designated horizons. The results show that in the surface (organic) horizon the main magnetic component is p robably derived from fly-ash, and that the concentration is up to 4 ti mes higher under pine. This is attributed to a combination of more eff icient scavenging properties of conifers and relatively low rates of o rganic turnover. In subsurface horizons the magnetic properties indica te that the higher acidity under pine has resulted in reduced concentr ations of ferrimagnetic and antiferromagnetic iron oxides. These signi ficant changes in min eralogy have taken place in 50-60 years.