Hoge fosfaatgehalten in bodems van voormalige landbouwgronden staan een snelle natuurontwikkeling in de weg. Het huidige verschralingsbeheer leidt op korte termijn niet tot de gewenste fosfaatverschraling. Het Overlegplatform Duinboeren en het Louis Bolk Instituut hebben in samenwerking met Vereniging Natuurmonumenten de mogelijkheden van ‘uitmijnen’ getoetst in het natuurontwikkelingsgebied het Hengstven.
Abandoned agricultural lands that are in conversion to nature conservation areas,often have a disbalance in regard to their chemical soil fertility.A major problem on sandy soils is the high soil phosphate level,inhibiting the development of nature target types.The current management on these abandoned agricultural lands,aiming to impoverish the soil, leads to a depression in dry matter production and consequently inhibits the removal of phosphate.To solve these problems,a grass-clover management is proposed including supplementary potassium fertilisation.In an experiment started in 2002 this management was tested. After 3 years the productivity of the plots that received potassium was about two times higher as compared to plots without potassium.Increase in phosphate removal was on average 15 kg phosphate per year.Calculations using field observations demonstrate that the proposed method of phosphate mining is able to achieve threshold phosphate values for nature target types within 10-20 years.