The increasing global demand for food, concerns over dwindling reserves of good quality phosphate rock and the climate-change impacts of fertiliser manufacture, fluctuating fertiliser prices, and the adverse environmental, social and economic consequences of phosphorus (P) pollution of water require the development of innovative and more sustainable solutions to the use and management of P on farms. Current systems of production rely on inputs of highly water-soluble fertilisers to maintain large reserves of background P in the soil. Recovery of applied P by crops is consequently low (<30%) and this inefficiency is not only wasteful of resources but also increases the risk of eutrophication through increased P loss in runoff from land. A peak in global phosphate rock production could occur within the next two decades whilst eutrophication is estimated to be costing the UK over £75 million per annum. A potential alternative and more sustainable strategy for P use in arable farming systems is to maintain a lower background of soil P but supplement this with more targeted P applications and/or by fertilisers that are more efficiently used, and/or fertilisers recovered from domestic or livestock wastewaters. We propose here that adoption of these more sustainable P use strategies will reduce growing costs and current dependence on elevated soil P-fertility, so will help to preserve finite global reserves of P and reduce export of P in runoff from land. In this proposal a multi-disciplinary, cross-industry research team will investigate and develop a new direction for P management that will improve P-use efficiency in arable crops, maximise recycling of wastewater P, reduce the pressure on rock phosphate reserves and minimise wider environmental impacts. Through multi-centre modelling, laboratory studies and field experiments we will compare and develop methods to improve P-use efficiency by (a) reducing the fixation of applied P by soils, (b) improving the accessibility of applied P to crops, and (c) improving the exploitation of soil P previously considered to be largely unavailable to crops. The magnitude of the economic and wider environmental benefits from maintaining lower soil P-fertility need to be quantified across a range of soil types and cropping systems. On completion, the project will deliver novel and profitable soil and fertiliser management strategies that will help farmers maintain the economic viability of their farm businesses and meet any future restrictions on P management under the Water Framework Directive. The project will have relevance across the spectrum of conventional, LEAF and organic farming systems and will involve overseas collaboration on what is internationally recognised as a key issue for sustainable farming and global food security. BBSRC funded project will develop mathematical models and optimisation techniques to describe phosphate movement and uptake by cropping systems.