Best Management Practices for Limiting Phosphorus Losses

In September 2015, a Memorandum of Cooperation (MOC) was signed between the Ontario Ministry of Agriculture, Food and Rural Affairs (OMAFRA), the Canadian Fertilizer Institute, and the Ontario Agri Business Association (OABA). This was to formalize a joint commitment to agricultural sustainability and environmental action.  The MOC partners are committed to helping Ontario farmers maximize crop yields with minimal environmental impact.  One of the main topics this group will be discussing is how to limit Phosphorus (P) losses from agricultural land in Ontario.  Through the Western Basin of Lake Erie Collaborative Agreement, Ontario has agreed to reduce phosphorus loading in Lake Erie in the next 10 years by 40%.

 

Let’s look a Best Management Practices (BMP’s) for limiting Phosphorus losses from our farms.  The first is simple, soil test so you can establish the right agronomic rate for various crops. Soil tests help to prevent over-fertilization and preventing over fertilization will reduce P loading of our rivers and lakes. BMP number 2: minimize erosion to limit particulate P losses. Minimum / zero tillage systems or cover crop utilization help reduce erosion by increasing soil organic matter over time, and improving soil structure, infiltration and water holding capacity, all things that reduce runoff.

 

A third BMP to reduce P losses is to place fertilizer or manure below the surface to reduce the interaction of added P with runoff water and lower the risk of P entering surface water from runoff.  Timing combined with P placement is also an effective strategy for both increasing P availability and uptake and preventing loss in annual crop systems.  In our cool springs, seed placing P or side-banding are far more effective practices for getting P to the crop when it needs it than broadcasting.  Also, placement near or with the seed means that application occurs after the high-risk spring runoff period.  Finally, establishing buffer strips along waterways can help catch and use P from spring and summer rainfall overland flow.  Keep in mind however, that buffer strips may be of limited use in preventing P loss during spring runoff because buffer strips are not always effective when runoff is moving over frozen ground and the vegetation not growing.