Critical level of P in soil and sediments related to risk of eutrophication, and optimising supply and utilization of P in agriculture

Dep. of Plant and Environmental Sciences

Project leader: Tore Krogstad
Co-workers: Gunnhild Riise (IPM), Anne Falk Øgaard, Marianne Bechmann (Bioforsk Jord og Miljø); Annbjørg Øverli Kristoffersen (Bioforsk Øst Apelsvoll)
Source of funding: The Research Council of Norway (main source of funding); Agr. Extention service SouthEast, The County Governor in Oslo/Akershus, The County Governor in Østfold, The MORSA project (financial contribution)
Project period: 2006-2007

Water quality in lakes, streams and rivers in districts with considerable agricultural activity, is largely classified as poor to very poor, due to large inputs of nutrients, in particular phosphorus. The negative development in water quality in spite of considerable abatement erosion strategies to reduce P runoff show that it is necessary also to reduce the P sources, i.e. the level of plant available P in the soil. High PAL level may also influence the lake sediment properties to adsorb and release P and may therefore both directly and indirectly influence on the water eutrophication processes. P is a limited resource world wide. A better utilization of P in the soil and an optimisation of applied P in agriculture are needed both with regard to agriculture and the environment.

Main goal: Identify areas with large risk of P release to watercourses, and increase the knowledge for a more sustainable use of P in agriculture with the aim to minimize eutrophication.

Sub goals:
1. To quantify the P-AL (plant available P) effect on the P change point for water soluble P in soil and on the equilibrium P concentration in particle affected water.
2. To quantify the effect of particle fractions, plant- and algal available P in erosion exposed soil on lake sediments P adsorption and P leaching properties.
3. To calibrate the P Index for implementation into agricultural environmental plans on field level.
4. Critical evaluation of the P fertilization norms and P calculation models in Norwegian agriculture to obtain more sustainable farming and good environmental management.


Updated: 27.03.06
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