Phosphorus is essential for growing crops, but it becomes a pollutant when too much of it moves into waterways, including major water bodies like Lake Erie.
How climate and management practices, such as tile drainage and tillage, impact the movement of nutrients from farm fields into the water system is the focus of much of the research done by Merrin MacRae, Associate Professor from the University of Waterloo’s Department of Geography and Environmental Management. She joins host Bernard Tobin to talk about the factors that lead to higher P losses as part of this episode of Agronomy Geeks — Ontario.
As MacRae notes, a distinction needs to be made between runoff coming from tile versus overland drainage. While the majority of runoff from a tiled field will flow through the tile, the amount of dissolved P is much higher in surface runoff.
So what can be done to mitigate the movement of the valuable macronutrient off of farmland? Here are some tidbits and recommendations discussed in this podcast:
- Protect the soil from erosion, and encourage infiltration, especially during non-growing season (such as cover crops and crop residue).
- Apply P in the spring, not in the fall, and incorporate it if possible.
- Consider increasing your crop diversity, not decreasing your tile drainage spacing (possibly include winter wheat, cover crops, forages.)
- Make it more difficult for water to flow off your fields (with strips, or buffers and if needed, waterways or WASCoBs (in concentrated flow areas.)
- Agronomy Geeks West, Ep. 12 — Don’t P in the Lake & Other Good Rules of Thumb
- Agricultural Run-Off A Main Focus of Great Lakes’ Eutrophication Concerns
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