Phosphorus is naturally found in all soils. It attaches itself to the soil sediments. “The amount of phosphorus in the soil is in part a function of the recent history of the soil,” said Jeff Dennis, Biologist at the Maine Department of Environmental Protection. “If the soil is, or in the last 100 years was, in agricultural use and thus enriched with manure and fertilizer, it’s likely to have more phosphorus associated with it than if it has always been a forest soil. The same is true for landscaped areas that are fertilized.”
As erosion occurs, the phosphorus begins to travel, landing in the man-made culverts and ditches where it has a direct line to water sources such as our lakes. The best way to prevent this is to reduce man-made interventions and keep the most natural flow of the runoff.
For those people living in a watershed area, it is important to be informed about products we use that have phosphorus in them, such as fertilizer for our lawns; and the effect that using them can have on our waters. This will increase the amount of phosphorus in the soil and in turn the amount that moves as erosion occurs.
The best thing to keep in mind is to try to reduce human intervention; keep land and water runoff as nature intended it to be whenever possible. Pay attention to watershed areas and work to reduce the amount of fertilizers that are used that will increase the amount of phosphorus in the soil.
The following list offers a few suggestions on ways humans can assist in producing less phosphorus.
This list was provided by the Minnesota Pollution Control Agency and offers recommendations for both the homeowner and farmer.
For the homeowner:
Use no-phosphorus fertilizer on lawns and gardens -
Be sure to check the bags when you buy them. Look for the package formula of nitrate-phosphorus-potassium, such as 22-0-15. The middle number, representing phosphorus, should be 0.
Keep grass clippings in the lawn -
When mowing the grass, avoid blowing grass clippings into the street, where they wash into storm sewers that drain to lakes and rivers.
Keep leaves and other organic matter out of the street
Again, streets drain to storm sewers, which in turn drain to rivers and lakes.
Sweep it -
Sweep up any grass clippings or fertilizer spills on driveways, sidewalks and streets.
Leave a wide strip of deep-rooted plants along shore lands.
Instead of planting and mowing turf grass here, plant wildflowers, ornamental grasses, shrubs or trees. These plantings absorb and filter runoff that contains nutrients and soil, as well as provide habitat for wildlife.
For the farmer:
Buffer strips help -
Leave a wide strip of deep-rooted plants along ditches, streams and lakes to absorb and filter runoff. Many programs, including ditch authorities, pay rent for these filter strips.
Change the plan on marginal land -
Plant marginal cropland to perennial crops or convert to water retention areas.
Use smarter drainage -
Install controlled drainage systems instead of traditional pattern tiling.
Manage the nutrients -
Follow nutrient management plans to ensure efficiencies and protect water resources.
Manage the manure -
Follow manure management plans, including setbacks from water resources when applying manure to fields.
Together when we remain educated on the best ways to reduce phosphorus in our lakes, our lakes will be much healthier for us all to enjoy as well as for future generations.