SOIL FERTILITY AND ITS IMPLICATIONS FOR THE RESTORATION OF HEATHLAND ON FARMLAND IN SOUTHERN BRITAIN

The distribution and concentration of extractable soil nutrients were compared between undisturbed heathland soil profiles and those of adjacent farmland which was formerly heathland. Heathland soils are of low fertility and pH. The conversion of heathland to farmland was found to have had profound long-tel m effects on both soil structure and chemistry. The well-defined mineral and organic soil horizons were mixed by ploughing, and the concentrations of extractable nitrogen, phosphorus, calcium and pH were significantly increased by the addition of fertilizers and lime. Following the cessation of farming, concentrations of phosphorus and nitrogen declined significantly so that after five to 13 years there were few differences compared with heartland soils. However, the effects of liming were persistent and this was thought to increase indirectly the fertility of the soil. It may be necessary to reduce the nutrient concentrations and pH of these soils as part of the management to restore heathland vegetation under conservation set-aside schemes.