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

A comparison is made of the magnetic properties of acid gleyed soils under 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 probably derived from fly-ash, and that the concentration is up to 4 times higher under pine. This is attributed to a combination of more efficient scavenging properties of conifers and relatively low rates of organic turnover. In subsurface horizons the magnetic properties indicate that the higher acidity under pine has resulted in reduced concentrations of ferrimagnetic and antiferromagnetic iron oxides. These significant changes in min eralogy have taken place in 50-60 years.