Mitigation options for diffuse phosphorus loss to water

Agriculture contributes significant loads of P to surface waters. The reductions in these diffuse P inputs necessary to help prevent eutrophication problems and/or assist in the restoration of water quality will require controls over both nutrient inputs and their subsequent transport in land runoff. Specific mitigation options include nutrient budgeting, input management, soil conservation, land use management and the establishment of riparian, and other buffer zones. The variable nature of diffuse P loss suggests that the best approach to control is through integrated management at a range of scales. Critical control concepts at the farm level include targeting source areas adequately maintaining P input loading rates within recommended limits and avoiding high-risk management actions. Since eutrophication is a natural phenomenon and with potential conflicts with the need to meet production targets and/or minimize loss of other nutrients (N), some assessment of acceptable levels of P loss, of cost effectiveness of options and some prioritization of goals are necessary to find optimal solutions. As the requirements of individual waterbodies differ, these solutions need to be site specific and their successful adoption requires an appreciation by farmers of the importance of minimizing agricultural P loss both as individuals and collectively within a catchment.