The project will find risk areas for leaching of dissolved phosphorous. As opposed to particulate phosphorous is dissolved phosphorous always directly available for water living organisms.
Agriculture is a main contributor of nutrients to water recipients and nutrient losses need to be reduced to meet good ecological status according to EU Water Framework Directive.
Losses of phosphorus (P) occur both in forms of dissolved P (DP) and particulate P (PP). While the bioavailability of PP form varies from 10 to 90 %, the DP is assumed to be readily bioavailable. Results from research projects and monitoring programs show extremely high DP losses from soil with small P sorption capacity (PSC).
The project will be performed in four steps:
- Using results from nation-wide soil survey in combination with other auxiliary geospatial data and results from environmental monitoring programs, we will identify sensitive areas of arable land prone to high DP losses.
- In the second step we will compare different laboratory methods, P fractionation procedures, XANES and P NMR to quantify P speciation and transformations and thereby develop guidelines for farmers and water authorities regarding identification of high-risk soils.
- Additionally, using intact soil columns we will study P leaching losses, as well as the effects of P fertilization on small PSC soils.
- Finally, in the last step we will scale-up our results and develop P leaching risk maps at national scale.
Targeting soils with small PSC will increase cost-efficiency of abatement measures and at the same time identify other areas of arable land which are more resilient and allow intensified agricultural production without threatening water quality.
Djodjic, F., M. Bieroza & L. Bergström. 2021. Land use, geology and soil properties control nutrient concentrations in headwater streams. Science of The Total Environment, Volume 772, 2021, 145108