SIS - Choices and opportunities for sustainable use of phosphorus in food production

The limited global reserves of plant available phosphorus (P) urges to develop strategies that focus on a more efficient use of P, both derived from P accumulated in soil, primary mineral sources and as derived from secondary waste stream sources. The former excessive P application and subsequent accumulation and immobilization of P in agricultural soil imply that soil P is a P source that may be exploited to some extent. More efficient use of P in soil requires more knowledge on both processes in soil-plant system and on methods for exploiting soil P. Availability of P in soil is a complex interaction between plant roots, soil biology and physical and chemical conditions in soil. This SIS will characterize Norwegian soil types’ ability to bind and release P for more precise recommendations for P application, and explore the possibilities to take advantage of root exudates and mycorrhiza to increase availability of P in soil and secondary products. The project will include research on the genes or gene family inducing root exudation by P starvation in Norwegian Brassica species and barley cultivars, and interaction between soil, plant roots and root exudates in vivo under P starvation will be revealed. Variations in P transport capacity for native mycorrhizal fungal genotypes, and conditions where mycorrhiza is most efficient will be explored. Urban sanitary wastewater and animal manure are two of the most important waste flows in Norway with respect to P. Organic P in manure will be characterized for increasing our knowledge about the organic P fraction in manure, and thereby increase our knowledge about availability of P in different types of manure. Efficient and feasible systems for recovering and recycling P from wastewater and animal manure in Norway will be identified, and the environmental life cycle impacts and socio-economic performance of such P systems will be examined.