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  • Lawns, Lakes, and Laws

  • Lawns, Lakes, and Laws Phosphorus the element Phosphorus and plants and soil Phosphorus and lakes Sources of urban phosphorus runoff Controlling phosphorus runoff

  • Phosphorus P Needed plant nutrient Most rare of the major life building blocks (C, H, O, N, P, S) 75% of nations use is mined in Florida

  • Phosphate PO4 Phosphorus is highly reactive Does not exist as an element in nature Combines with oxygen to form phosphate

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

  • Phosphorus and plants Function: Energy transfer and cell division Deficiency: Stunted growth Deficiency: Purple or yellow leaves Deficiency: More common in cool springRARE!

  • Phosphorus in soilPools of phosphorus storage in soil< 10 to > 300 lbs/acre < 1 lbs/acre

  • Soil solution phosphorus (H2PO4-)Form taken up by plantsMobile formSmall fraction of total soil P (< 1 lb/acre) Phosphorus in soil

  • Active soil phosphorus In equilibrium with solution P < 10 lbs/acre to > 300 lbs/acre Tightly adhered to soil particlesPhosphorus in soil

  • Phosphorus and soil pH6.0 pH7.0 pHAvailability of phosphorus vs. soil pH

  • Phosphorus fertilization Recommended on turf when: Solution P + Soil P < 25 ppm

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

  • High growthLow lightLow oxygenImpacts of phosphorus

  • 10,000s YEARS IN NATURAL CONDITIONS10s to 100s YEARS UNDER HUMAN INFLUENCESpeeding aging of lakes

  • Tropic State

  • A factor of 1,000 less!It takes a 1,000 times less phosphorus to turn a lake green than keep a lawn healthy60 parts per BILLION30 parts per MILLION

  • As phosphorus goes up, algae goes up, and water clarity goes down

  • Secchi DiskSecchi disk is a low-tech way to measure water clarity and determine a lakes tropic state

  • 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

  • Sources of phosphorus When it rains, it pollutesThink watersheds!

  • Types of runoff pollution Sediment soil erosion, street grit Nutrients nitrogen and phosphorus Bacteria - wildlife, pets, sewage Organics manure, leaves, grass Toxics lead, zinc, copper, pesticides

  • Impervious surfacesResidential Areas = 50% Impervious

  • Every city lot is waterfront property!

  • StreetsLawnsDrivewaysRoofsSidewalksSources of phosphorus runoffBannerman - Wisconsin DNR

  • Soluble plant PSoil solution PSources of phosphorus runoff from lawns

  • Sources of phosphorus runoff from lawns Runoff from plant material (dissolved) Misapplied fertilizer (dissolved) Runoff from soil solution (dissolved) Attached to eroded soil (particulate)

  • Sources of phosphorus runoff from lawns Runoff from plant material (dissolved) Misapplied fertilizer (dissolved) Runoff from soil solution (dissolved) Attached to eroded soil (particulate)?

  • Phosphorus runoff by land use

    Lbs./Acre/Year SourceSoluble PParticulate P Bare cropland0.1033.20 Plowed corn0.2713.50 No-till corn0.981.90 Hayland0.390.02 Lawns0.360.00 Sources: Sharpley and Menzel 1987; Rehm, 1997, Kussow, 2000.

  • Grass clippings Contain 0.13 lbs P / 1000 sq. ft. / year Thats 0.65 lbs P / ave. yard / year

  • Controlling P runoff is package deal

  • How much P comes from leaves? 0.003 to 0.007 lbs P / hardwood / year If half the leaves from boulevard trees hit the street, a city block can produce 0.05 to 0.10 lbs P / year in runoff

  • Phosphorus fertilization Apply according to soil test Important when seeding or sodding Rarely needed on est. lawns in Metro Sweep up overspread & spilled material

  • Reading the bag Given in % phosphate by weight Phosphate (P2O5) not phosphorus (P)! P = P2O5 2.29Look for the middle number! N - P - K

  • The best way to determine P need Rare as meteor hits in the metro Poor sample technique gives poor results Recommended when troubleshootingTaking a soil test

  • Sample front and back lawn separately Sample randomly, avoid odd areas Mix in plastic bucket send 1 pint to lab

  • Two phosphorus tests used in Minnesota based on soil pH: Bray 1 pH 7.4 Olsen pH > 7.4

  • Selecting fert. with needed N-P-K balance 1,000 sq. ft.??? How big is my lawn? Setting spreader application rate Soil test? Calibrate? Get a life!!!Application challenges

  • State phosphorus lawn fertilizer law Local fertilizer ordinances Use vs. Sale regulationThe law and the lawn

  • Minnesota phosphorus lawn fertilizer law Passed in 2002 Goes into full effect in 2004 Concerns phosphorus fertilizer - mostly Treats metro and non-metro differently First in nation - has drawn attention

  • MN lawn fertilizer lawMetro area (seven county) - Starts 2004 0% P2O5 fertilizer required, unless: - Newly seeded or sodded lawn - Soil test shows need- Applied by trained golf course staff

  • MN lawn fertilizer lawNon-metro area - Starts 2004 No greater than 3% P2O5 fertilizer required, unless: - Newly seeded or sodded lawn - Soil test shows need- Applied by certified golf course staff Cities can opt to adopt 0% P2O5 limit

  • MN lawn fertilizer law When liquid product is used in non-metro area, rate is limited to 0.3 lbs. P2O5 per 1,000 sq. ft. - unless need for higher rates is shown. When there is need to apply phosphorus lawn fertilizer at higher rates, University of Minnesota recommendations are to be followed.

  • MN lawn fertilizer lawProhibited to apply fertilizer (any type) to impervious surfaces.Examples: Streets, sidewalks, driveways.Started 2002

  • MN lawn fertilizer law Preempts local ordinances on fertilizer use Allows pre-2002 local ordinances on fertilizer sales to stand Enforcement by local units of government as a petty misdemeanor

  • City of Burnsville ordinance - before state law No application between Nov 15 - April 1 Clean fertilizer from impervious surfaces Keep outside 20 foot buffer around water Apply no greater than 0% P2O5 fertilizer unless new lawn or soil test shows need Notice of law needs to be posted in stores

  • City of Burnsville ordinance - after state law No application between Nov 15 - April 1 Clean fertilizer from impervious surfaces Keep outside 20 foot buffer around water Apply no greater than 0% P2O5 fertilizer unless new lawn or soil test shows need Notice of law needs to be posted in storesLocals can no longer regulate fertilizer use

  • Publication on the new law800-877-6300 to place orders

  • 0% P2O5 fertilizers becoming widely available . . .

  • On existing lawns - Use 0% P2O5 fertilizer unless a need for phosphorus is shown (soil test) - Soil test if lawn if failing to thrive - Apply to UM recommendations when phosphorus is used What to advise . . .

  • On new lawns - Soil test to 6 depth - No test? Apply 2 lbs. P2O5/1,000 sq. ft. - Mix fertilizer well into top 6 of soilWhat to advise . . .

  • What to advise . . . All lawns - Sweep up, rake up, pick up - Soil test if interested in baseline

  • What to advise . . . Future? practices to increase infiltrationRain garden in Maplewood, MN

  • Spring / Fall messages in the media Web site with resources for citizens, cities, and teachers/students TV weather broadcast / clean water featurewww.cleanwatermn.org

  • Information usedA 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-6795Phosphorus Transport and Availability in Surface Waters. Gyles Randall, et.al. U of MN Extension Service. Pub. FO-6796Soil Test Interpretation and Fertilizer Management for Lawns, Turf, Gardens, and Landscape Plants. Carl Rosen, et.al. University of Minnesota Extension Service. Pub. BU-1731Understanding Lake Data. Byron Shaw, et.al. University of Wisconsin Extension. Pub. G3582

  • Ron StrussExtension Educator University of Minnesota Extension Service651-215-1950 rstruss@umn.edu

  • Title slide: Lawns, Lakes, and LawsOverview of presentationThe overall issue and concern: The greening of our lakes and slow moving rivers with excessive algae growth.Phosphorus, known also by its chemical symbol P, is a needed plant nutrient. It is the most rare of the major life building blocks, which in addition to phosphorus, includes carbon, hydrogen, oxygen, nitrogen, and sulfur.

    Phosphorus is mined from the earth in the form of phosphate rock. 75% of the phosphorus used in the United States is mined in Florida. Mined phosphorus is a limited, non-renewable resource. Typically after mining, phosphate rock is reacted with acids to produce different phosphate products.

    Picture shows phosphate rock mining in Florida.Highly reactive with oxygen, phosphorus is not found in its elemental form in nature. It natural systems like soil a