The IMPROVE-P project’s overall goal is to design improved P recycling systems for organic farming systems. This includes:

(a) enhanced P recycling using recycling P fertilizers as alternative P fertilizers (APF) (permitted APF: e.g. treated household or food processing waste, meat and bone meal, wood ash, basic slag, etc.; currently prohibited APF: e.g. incineration slags, cleaned sewage ashes),
(b) higher plant P use efficiency due to enhanced agronomic measures (e.g. use of adapted cultivars, application techniques, P mobilization by cover cropping), and
(c) improved P availability to plants by application of Plant Growth Promoting Rhizobacteria (PGPR).

Both organic and inorganic sources of fertilizer P may be associated with some contamination by pollutants. Therefore, for a holistic evaluation the project aims to develop tools to determine which APF will minimize environmental damage by

(d) compiling available data about life cycle assessment (LCA) of the most important APF,
(e) modelling the risks of soil accumulation of pollutants, and
(f) development of an index value to assess APF suitability for organic farming.

Optimum practices for organic farming will be identified using an integrated approach including:

- a review of existing data (WP1),
- experimental studies and modelling assessing the suitability of APF in comparison to currently used rock phosphates (WP2),
- assessment of the effects of addition of PGPRs and implementation of selected agronomic techniques for enhanced P bioavailability (WP3),
- and assessment of stakeholders’ perceptions of APF (WP4).
- The project’s dissemination activities in WP0 will target stakeholders, consumers and policy makers.

The project combines four strategies/research methodologies:

1. Mining data from literature on current P status and management in organic farming, and publishing an analysis on the potential for use of APF in organic farming systems. This analysis will be based on existing data, including a comprehensive review of peer reviewed and “grey” literature (WP1).
2. Characterization of APF by chemical analysis and by plant studies in pots under greenhouse and growth chamber conditions, and in field experiments to investigate the influence of chemical form on P bioavailability depending on soil characteristics and fertilizer application technique (WP2).
3.  Designing  innovative  systems  to  enhance  P  bioavailability  by application  of  PGPRs  and implementation of agronomic strategies for improved P mobilization (efficient cultivars, cover crops) (WP3).
4. Discussions with stakeholders concerning applicability of APF in organic farming, mainly by workshop in the participating countries and on international congresses/meetings (WP4).