Phosphorus adsorption by soils from heathlands in southern England in relation to successional change.
Abstract
Determinations of the phosphorus adsorption characteristics of a range of heathland soils are described and related to differences in phosphorus economy as a result of heather burning, and the consequent release of phosphorus from organic matter components of the system. The results show that even in the absence of grazing or management, sites are likely to remain as open Calluna-dominated heathland where the phosphorus adsorption maximum of the soil is less than about 70 μg P/g soil. However, in the absence of grazing, invasion by Ulex europaeus is likely where the phosphorus adsorption maximum is between 70 and 700 μg of P/g soil, and control of gorse may be required if Calluna dominated conditions are to be maintained. Where the phosphorus adsorption maximum of the soil exceeds 700 μg of P/g soil, succession to birch wood is most likely if grazing or positive management techniques are not maintained. Variations in adsorption maxima from soils within a single site suggest that persistence of open heathland upon some wooded sites may be due to local variations in soil. The implications are that suitable heathland management on any one site may not be adequate where soil conditions are different, and that drastic management techniques are required to maintain, or even re-create open Calluna heathland on soils with higher phosphorus adsorption characteristics.