Lawns, Lakes, and LawsLawns, Lakes, and Laws
Lawns, Lakes, and LawsLawns, Lakes, and Laws
Phosphorus the element
Phosphorus and plants and soil
Phosphorus and lakes
Sources of urban phosphorus runoff Controlling phosphorus runoff
PhosphorusPhosphorus“P”“P”
• Needed plant nutrientNeeded plant nutrient
• Most rare of the majorMost rare of the major “life building blocks” (C, H, O, N, P, S) “life building blocks” (C, H, O, N, P, S)
• 75% of nation’s use is mined in Florida75% of nation’s use is mined in Florida
PhosphatePhosphatePOPO44
• Phosphorus is highly reactivePhosphorus is highly reactive
• Does not exist as an element in natureDoes not exist as an element in nature
• Combines with oxygen to formCombines with oxygen to form phosphate phosphate
PhosphorusPhosphorusand plantsand plants
• Function:Function: Energy transfer and cell divisionEnergy transfer and cell division
• Deficiency:Deficiency: Stunted growth Stunted growth
• Deficiency:Deficiency: Purple or yellow leaves Purple or yellow leaves
• Deficiency:Deficiency: More common in cool spring More common in cool spring
PhosphorusPhosphorusand plantsand plants
• Function:Function: Energy transfer and cell divisionEnergy transfer and cell division
• Deficiency:Deficiency: Stunted growth Stunted growth
• Deficiency:Deficiency: Purple or yellow leaves Purple or yellow leaves
• Deficiency:Deficiency: More common in cool spring More common in cool springRARE!RARE!
Phosphorus in soilPhosphorus in soil
““Pools” of phosphorus storage in soilPools” of phosphorus storage in soil
< 10 to > 300 < 10 to > 300 lbs/acre lbs/acre
< 1 lbs/acre< 1 lbs/acre
ActiveSoilP
SoilSolutionP
• Soil solution phosphorus (HSoil solution phosphorus (H22POPO44--))
– Form taken up by plantsForm taken up by plants– Mobile formMobile form– Small fraction of total soil P (< 1 lb/acre) Small fraction of total soil P (< 1 lb/acre)
Phosphorus in soilPhosphorus in soil
ActiveSoilP
SoilSolutionP
• Active soil phosphorusActive soil phosphorus– In equilibrium with solution PIn equilibrium with solution P– < 10 lbs/acre to > 300 lbs/acre< 10 lbs/acre to > 300 lbs/acre– Tightly adhered to soil particlesTightly adhered to soil particles
ActiveSoilP
SoilSolutionP
Phosphorus in soilPhosphorus in soil
Phosphorus and soil pHPhosphorus and soil pH
6.0 pH6.0 pH 7.0 pH7.0 pH
Availability of phosphorus vs. soil pHAvailability of phosphorus vs. soil pH
Phosphorus Phosphorus fertilizationfertilization
• Recommended on turf when:Recommended on turf when:
Solution P + Soil P < 25 ppmSolution P + Soil P < 25 ppm
Phosphorus Phosphorus and lakesand lakes
• Most limiting plant nutrient in lakesMost limiting plant nutrient in lakes
• Algae “blooms” = low oxygen and smellAlgae “blooms” = low oxygen and smell
• 1 lbs P = 300 lbs to 500 lbs algae1 lbs P = 300 lbs to 500 lbs algae
High growth
Low light
Low oxygen
Impacts of phosphorusImpacts of phosphorus
10,000’s YEARS IN NATURAL CONDITIONS
10’s to 100’s YEARS UNDER HUMAN INFLUENCE
Speeding aging of lakesSpeeding aging of lakes
Tropic StateTropic State (ppb)
A factor of 1,000 less!A factor of 1,000 less!
It takes a 1,000 times less phosphorus to It takes a 1,000 times less phosphorus to turn a lake green than keep a lawn healthyturn a lake green than keep a lawn healthy
60 parts per BILLION
30 parts per MILLION
As phosphorus goes up, algae goes As phosphorus goes up, algae goes up, and water clarity goes downup, and water clarity goes down
Secchi DiskSecchi Disk
Secchi disk is a Secchi disk is a low-tech way to low-tech way to measure water measure water clarity and clarity and determine a lake’s determine a lake’s tropic state tropic state
Experimental Experimental Lake Area StudyLake Area Study(Fisheries and Oceans Canada)(Fisheries and Oceans Canada)
• Top-to-bottom curtain divides lake in twoTop-to-bottom curtain divides lake in two
• Carbon and nitrogen added to one sideCarbon and nitrogen added to one side
• Carbon, nitrogen and Carbon, nitrogen and phosphorusphosphorus added added to other – effect is clear to see to other – effect is clear to see
Sources of phosphorusSources of phosphorus“When it rains, it pollutes”“When it rains, it pollutes”
Think watersheds!Think watersheds!
TypesTypesof runoff of runoff pollutionpollution
• SedimentSediment – soil erosion, street grit – soil erosion, street grit• NutrientsNutrients – nitrogen and phosphorus – nitrogen and phosphorus• BacteriaBacteria - wildlife, pets, sewage - wildlife, pets, sewage• OrganicsOrganics – manure, leaves, grass – manure, leaves, grass• ToxicsToxics – lead, zinc, copper, pesticides – lead, zinc, copper, pesticides
Impervious Impervious surfacessurfaces
Residential Areas = Residential Areas = 50% Impervious50% Impervious
Every city lot is waterfront property!Every city lot is waterfront property!
0% 10% 20% 30% 40% 50%
Streets
Lawns
Driveways
Roofs
Sidewalks
Sources of phosphorus runoffSources of phosphorus runoffBannerman - Wisconsin DNR
Soluble plant P
Soil solution P
Soil particle P Product
Sources of phosphorus runoff from lawns
Sources of phosphorusSources of phosphorusrunoff from lawnsrunoff from lawns
• Runoff from plant material (dissolved)Runoff from plant material (dissolved)
• Misapplied fertilizer (dissolved) Misapplied fertilizer (dissolved)
• Runoff from soil solution (dissolved)Runoff from soil solution (dissolved)
• Attached to eroded soil (particulate)Attached to eroded soil (particulate)
LIK
EL
YH
OO
D
Sources of phosphorusSources of phosphorusrunoff from lawnsrunoff from lawns
• Runoff from plant material (dissolved)Runoff from plant material (dissolved)
• Misapplied fertilizer (dissolved) Misapplied fertilizer (dissolved)
• Runoff from soil solution (dissolved)Runoff from soil solution (dissolved)
• Attached to eroded soil (particulate)Attached to eroded soil (particulate)
LIK
EL
YH
OO
D
??
Lbs./Acre/YearLbs./Acre/Year
SourceSource Soluble PSoluble P Particulate PParticulate P
Bare croplandBare cropland 0.100.10 33.2033.20
Plowed cornPlowed corn 0.270.27 13.5013.50
No-till cornNo-till corn 0.980.98 1.901.90
HaylandHayland 0.390.39 0.020.02
LawnsLawns 0.360.36 0.000.00 Sources: Sharpley and Menzel 1987; Rehm, 1997, Kussow, 2000.Sources: Sharpley and Menzel 1987; Rehm, 1997, Kussow, 2000.
Phosphorus runoff by land usePhosphorus runoff by land use
SO
IL E
RO
SIO
N
Grass clippingsGrass clippings
• Contain 0.13 lbs P / 1000 sq. ft. / yearContain 0.13 lbs P / 1000 sq. ft. / year
• That’s 0.65 lbs P / ave. yard / yearThat’s 0.65 lbs P / ave. yard / year
Controlling Controlling “P” runoff is “P” runoff is package dealpackage deal
How much How much “P” comes “P” comes from leaves?from leaves?
• 0.003 to 0.0070.003 to 0.007 lbs P / hardwood / yearlbs P / hardwood / year
• If half the leaves from boulevard treesIf half the leaves from boulevard trees hit the street, a city block can produce hit the street, a city block can produce 0.05 to 0.10 lbs P / year in runoff 0.05 to 0.10 lbs P / year in runoff
Phosphorus Phosphorus fertilizationfertilization
• Apply according to soil testApply according to soil test• Important when seeding or soddingImportant when seeding or sodding• Rarely needed on est. lawns in MetroRarely needed on est. lawns in Metro• Sweep up overspread & spilled materialSweep up overspread & spilled material
Reading the bagReading the bag
• Given in % phosphate by weightGiven in % phosphate by weight
• Phosphate (PPhosphate (P22OO55) not phosphorus (P)!) not phosphorus (P)!
• P = PP = P22OO5 5 ÷ 2.29÷ 2.29
Look for the middle Look for the middle number!number!
N - P - KN - P - K
• The best way to determine P needThe best way to determine P need• Rare as meteor hits in the metroRare as meteor hits in the metro• Poor sample technique gives poor resultsPoor sample technique gives poor results• Recommended when “troubleshooting”Recommended when “troubleshooting”
TakingTakinga soil testa soil test
• Selecting fert. with needed N-P-K balanceSelecting fert. with needed N-P-K balance• 1,000 sq. ft.??? How big is my lawn?1,000 sq. ft.??? How big is my lawn?• Setting spreader application rateSetting spreader application rate• Soil test? Calibrate? Get a life!!!Soil test? Calibrate? Get a life!!!
Application Application
challengeschallenges
• State phosphorus lawn fertilizer lawState phosphorus lawn fertilizer law• Local fertilizer ordinancesLocal fertilizer ordinances• “ “Use” vs. “Sale” regulationUse” vs. “Sale” regulation
The lawThe law
and the lawnand the lawn
Minnesota phosphorus Minnesota phosphorus lawn fertilizer lawlawn fertilizer law
• Passed in 2002Passed in 2002
• Goes into full effect in 2004Goes into full effect in 2004
• Concerns phosphorus fertilizer - mostlyConcerns phosphorus fertilizer - mostly
• Treats metro and non-metro differentlyTreats metro and non-metro differently
• First in nation - has drawn attentionFirst in nation - has drawn attention
MN lawn fertilizer lawMN lawn fertilizer law
Metro area (seven county) - Starts 2004Metro area (seven county) - Starts 2004
• 0% P0% P22OO55 fertilizer required, unless: fertilizer required, unless:
- Newly seeded or sodded lawn- Newly seeded or sodded lawn
- Soil test shows need- Soil test shows need
- Applied by trained golf course staff- Applied by trained golf course staff
MN lawn fertilizer lawMN lawn fertilizer law
Non-metro area - Starts 2004Non-metro area - Starts 2004
• No greater than No greater than 3% P3% P22OO55 fertilizer fertilizer required, unless: required, unless:
- Newly seeded or sodded lawn- Newly seeded or sodded lawn
- Soil test shows need- Soil test shows need
- Applied by certified golf course staff- Applied by certified golf course staff
• Cities can opt to adopt Cities can opt to adopt 0% P0% P22OO55 limit limit
MN lawn fertilizer lawMN lawn fertilizer law
• When liquid product is used in non-metroWhen liquid product is used in non-metro area, rate is limited to 0.3 lbs 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 phosphorusWhen there is need to apply phosphorus lawn fertilizer at higher rates, University lawn fertilizer at higher rates, University of Minnesota recommendations are to be of Minnesota recommendations are to be followed. followed.
MN lawn fertilizer lawMN lawn fertilizer law
ProhibitedProhibited to apply to apply fertilizer (any type) to fertilizer (any type) to impervious surfaces.impervious surfaces.
Examples: Streets, Examples: Streets, sidewalks, driveways.sidewalks, driveways.
Started 2002Started 2002
MN lawn fertilizer lawMN lawn fertilizer law
• Preempts local ordinances on fertilizer Preempts local ordinances on fertilizer useuse
• Allows pre-2002 local ordinances onAllows pre-2002 local ordinances onfertilizer fertilizer salessales to stand to stand
• Enforcement by local units ofEnforcement by local units ofgovernment as a petty misdemeanorgovernment as a petty misdemeanor
City of Burnsville City of Burnsville ordinance - ordinance - before state lawbefore state law
• No application between No application between Nov 15 - April 1Nov 15 - April 1
• Clean fertilizer from impervious surfacesClean fertilizer from impervious surfaces
• Keep outside Keep outside 20 foot buffer20 foot buffer around water around water
• Apply no greater than Apply no greater than 0% P0% P22OO55 fertilizer fertilizer unless new lawn or soil test shows need unless new lawn or soil test shows need
• Notice of law needs to be posted in storesNotice of law needs to be posted in stores
City of Burnsville City of Burnsville ordinance - ordinance - after state lawafter state law
• No application between No application between Nov 15 - April 1Nov 15 - April 1
• Clean fertilizer from impervious surfacesClean fertilizer from impervious surfaces
• Keep outside Keep outside 20 foot buffer20 foot buffer around water around water
• Apply no greater than Apply no greater than 0% P0% P22OO55 fertilizer fertilizer unless new lawn or soil test shows need unless new lawn or soil test shows need
• Notice of law needs to be posted in storesNotice of law needs to be posted in stores
Locals can no longer regulate fertiliz
er use
Publication on Publication on the new lawthe new law
800-877-6300800-877-6300to place ordersto place orders
0% P0% P22OO5 5 fertilizers becoming fertilizers becoming
widely available . . .widely available . . .
• On existing lawnsOn existing lawns
- Use 0% P- Use 0% P22OO5 5 fertilizer unless a needfertilizer unless a need for phosphorus is shown (soil test) for phosphorus is shown (soil test)
- Soil test if lawn if failing to thrive- Soil test if lawn if failing to thrive
- Apply to UM recommendations when- Apply to UM recommendations when phosphorus is used phosphorus is used
What to advise . . .What to advise . . .
• On new lawnsOn new lawns
- Soil test to 6” depth- Soil test to 6” depth
- No test? Apply 2 lbs. P- No test? Apply 2 lbs. P22OO55/1,000 sq. ft./1,000 sq. ft.
- Mix fertilizer well into top 6” of soil- Mix fertilizer well into top 6” of soil
What to advise . . .What to advise . . .
What to advise . . .What to advise . . .• All lawnsAll lawns
- Sweep up, rake up, pick up- Sweep up, rake up, pick up
- Soil test if interested in “baseline” - Soil test if interested in “baseline”
What to advise . . .What to advise . . .• Future? – Future? – practices to increase practices to increase infiltrationinfiltration
Rain garden in Maplewood, MN
• Spring / Fall messages in the mediaSpring / Fall messages in the media
• Web site with resources for citizens,Web site with resources for citizens, cities, and teachers/students cities, and teachers/students
• TV weather broadcast / clean waterTV weather broadcast / clean water feature feature
www.cleanwatermn.org
Ron StrussRon StrussExtension EducatorExtension EducatorUniversity of Minnesota Extension ServiceUniversity of Minnesota Extension Service
[email protected]@umn.edu
