Lawns, Lakes, and Laws

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

Issue: Over-enrichment of lakes and rivers

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)


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 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 ppm*Solution P + Soil P < 25 ppm* * Bray P1 test* Bray P1 test

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%

Sources of phosphorus runoffSources of phosphorus runoff

Streets

Lawns

Driveways

Roofs

Sidewalks

Bannerman - 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

Phosphorus Phosphorus fertilizationfertilization

• MN law restricts P lawn fertilizer useMN law restricts P lawn fertilizer use• Rarely needed on established lawnsRarely needed on established lawns• Important when seeding or soddingImportant when seeding or sodding• Apply according to soil testApply according to soil test

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

Reading the bagReading the bag

Look for “the zero in Look for “the zero in middle” for middle” for

phosphorus-freephosphorus-free

• 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

• First law passed 2002; revised 2004assed 2002; revised 2004

• Zero P rule goes statewide Jan. 1, 2005Zero P rule goes statewide Jan. 1, 2005

• Concerns phosphorus Concerns phosphorus lawnlawn fertilizer fertilizer

• Involves Involves useuse, not sale, of fertilizer, not sale, of fertilizer

• First in nation - has drawn attentionFirst in nation - has drawn attention

MN lawn fertilizer lawMN lawn fertilizer law

A restriction, not a ban:A restriction, not a ban:

• 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


• When there is need to apply phosphorus,When there is need to apply phosphorus, University of MN recommendations are University of MN recommendations are to be followed to be followed

• Law administered by the MinnesotaLaw administered by the Minnesota Department of Agriculture Department of Agriculture

• Enforcement by local units of Enforcement by local units of government as a petty misdemeanor government as a petty misdemeanor


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.

Sweep up over-spread Sweep up over-spread material.material.


• Preempts local ordinances on fertilizer Preempts local ordinances on fertilizer useuse

• Law does not restrict what stores canLaw does not restrict what stores can sell or what customers can buy sell or what customers can buy

• Allows pre-2002 local ordinances onAllows pre-2002 local ordinances onfertilizer fertilizer salessales to stand to stand

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


• Leftover phosphorus lawn fertilizerLeftover phosphorus lawn fertilizer

- In Greater MN, leftover phosphorus- In Greater MN, leftover phosphorus lawn fertilizer can be used up on lawns lawn fertilizer can be used up on lawns

- In Twin Cities Metro, leftover- In Twin Cities Metro, leftover phosphorus lawn fertilizer can be used phosphorus lawn fertilizer can be used on non-lawn applications (garden) on non-lawn applications (garden)

- If a lawn fertilizer contains a pesticide,- If a lawn fertilizer contains a pesticide, it cannot be used for non-lawn use – it cannot be used for non-lawn use – dispose as household hazardous waste dispose as household hazardous waste


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 Burnsville, MN

• Spring / Fall messages in the mediaSpring / Fall messages in the media

• Website with resources for citizens,Website 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

Lawns, Lakes, and Laws

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