Mapping Phosphorus hot spots - the ticket to Carbon sesquestration in lowland soils

Rewetting organic lowland soils can reduce CO2 emission by 15 tons/ha/y. However, rewetting may cause excessive release of iron-oxide bound phosphorus (P). Current methods to predict P hot-spots are unreliable and lacking a mechanistic basis. In PhosCarb we will study the biological and chemical P mobilisation and immobilisation processes. New field methods (litter bags, iron stripes) will be used to quantify iron reduction and concomitant P release, while lab studies will unravel the fluxes of P between pools with particular focus on microbially mediated P precipitates. Flow path analysis and reactive transport modelling will be used to predict, if high net in-situ P release results in high P export. Our P mapping approach can help to expand the lowland area that can be rewetted as the prediction is more precise and eventually P mitigation
measures can be implemented at hot-spots or P risk areas, with a potential to lower the CO2 emission of Danish lowland soils by +1 mill ton/y.