ABSTRACT
Before the 1980s research into phosphorus (P) in agro-ecosystems focussed on crop growth, yield and quality. Contemporary interest in the environmental behaviour of P is now largely concentrated on its movement to rivers, lakes and seas. It was thought that, unlike nitrates, phosphates were held so strongly within the soil matrix that movement to natural waters was negligible. However, the increased incidence of eutrophic waters, algal blooms and other ecologically damaging effects for which P is a major contributing factor, indicate this not to be the case. Agricultural land is now recognised to be the largest nonpoint source of P reaching surface waters. Morse et al. (1993) estimate that 43% of the phosphorus inputs into surface waters in the UK are attributable to agriculture. The buildup of P levels in soils over the last 45 years also had an impact upon plant species diversity in grassland meadows and semi-natural habitats. This chapter addresses:
• the reasons for the increase in P movement within the environment;
• the potential environmental and human health implications of this increase;
• strategies to minimise P losses and maximise usage within agroecosystems.
