Lawns, Lakes

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Lawns, Storm Water, and You
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Over-enrichment of waterbodies
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Phosphorusand plants

• Function Energy transfer and cell division
• Deficiency Stunted growth
• Deficiency Purple or yellow leaves
• Deficiency More common in cool spring

RARE!
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Impacts of phosphorus
High growth
Low light
Low oxygen

• Most limiting plant nutrient in waterbodies
• Algae blooms low oxygen and smell
• 1 lbs P 300 lbs to 500 lbs algae

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A factor of 1,000 less!
60 parts per BILLION
30 parts per MILLION
It takes a 1,000 times less phosphorus to turn a
waterbody green than keep a lawn healthy
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Experimental Lake Area Study(Fisheries and
Oceans Canada)

• Top-to-bottom curtain divides lake in two
• Carbon and nitrogen added to one side
• Carbon, nitrogen and phosphorus added to
  other effect is clear to see

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Every city lot is waterfront property!
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Sources of phosphorus runoff
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Controlling P runoff is a package deal
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Reading the bag
Look for the middle number!N - P - K

• Rarely needed on established lawns
• Important when seeding or sodding
• Apply according to soil test

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Reading the bag
Look for the zero in middle for phosphorus-free
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What to advise . . .

• On existing lawns
• - Use 0 or low P2O5 fertilizer unless a
  need for phosphorus is shown (soil test)
• - Soil test if lawn is failing to thrive
• - Apply per soil test recommendations when
  phosphorus is used

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What to advise . . .

• All lawns
• - Sweep up, rake up, pick up
• - Soil test if interested in baseline

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How to reduce nutrients

• Future? practices to increase infiltration
• Buffer strips around water bodies help to
  reduce nutrient loading

Rain garden in Burnsville, MN
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Things the City will do to mitigate effects of
phosphorus

• Investigate Use of algaecide to control algal
  blooms
• Investigate use of plants and floating islands to
  control available phosphorus
• Investigate the introduction of grass carp to
  control algal growth

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Things residents can do to control phosphorus
impact

• Apply Low or No Phosphorus fertilizer to lawns
• Maintain filter/buffer strips to help lessen
  phosphorus loads on basins
• Maintain grass height at least 3 tall which
  promotes better grass health and lessens runoff
• Bag leaves and grass or insure they are not
  deposited into basins

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Contact Information
David Scanlan, Storm Water Utility, 323 -
8172 Jesse Leckband, Storm Water Utility, 323 -
8173
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Information used
A Primer on Limnology. Bruce Monson. University
of Minnesota Water Resources Center. The Nature
of Phosphorus in Soils. Lowell Busman, et.al.
University of Minnesota Extension Service. Pub.
FO-6795 Phosphorus Transport and Availability in
Surface Waters. Gyles Randall, et.al. U of MN
Extension Service. Pub. FO-6796 Soil Test
Interpretation and Fertilizer Management for
Lawns, Turf, Gardens, and Landscape Plants. Carl
Rosen, et.al. University of Minnesota Extension
Service. Pub. BU-1731 Understanding Lake Data.
Byron Shaw, et.al. University of Wisconsin
Extension. Pub. G3582