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

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

Post on 27-Dec-2015

217 views

Category:

Documents

3 download

Embed Size (px)

TRANSCRIPT

<ul><li><p>Lawns, Lakes, and Laws</p></li><li><p>Lawns, Lakes, and Laws Phosphorus the element Phosphorus and plants and soil Phosphorus and lakes Sources of urban phosphorus runoff Controlling phosphorus runoff </p></li><li><p>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</p></li><li><p>Phosphate PO4 Phosphorus is highly reactive Does not exist as an element in nature Combines with oxygen to form phosphate</p></li><li><p>Phosphorus and plants Function: Energy transfer and cell division Deficiency: Stunted growth Deficiency: Purple or yellow leaves Deficiency: More common in cool spring</p></li><li><p>Phosphorus and plants Function: Energy transfer and cell division Deficiency: Stunted growth Deficiency: Purple or yellow leaves Deficiency: More common in cool springRARE!</p></li><li><p>Phosphorus in soilPools of phosphorus storage in soil&lt; 10 to &gt; 300 lbs/acre &lt; 1 lbs/acre</p></li><li><p>Soil solution phosphorus (H2PO4-)Form taken up by plantsMobile formSmall fraction of total soil P (&lt; 1 lb/acre) Phosphorus in soil</p></li><li><p> Active soil phosphorus In equilibrium with solution P &lt; 10 lbs/acre to &gt; 300 lbs/acre Tightly adhered to soil particlesPhosphorus in soil</p></li><li><p>Phosphorus and soil pH6.0 pH7.0 pHAvailability of phosphorus vs. soil pH</p></li><li><p>Phosphorus fertilization Recommended on turf when: Solution P + Soil P &lt; 25 ppm</p></li><li><p>Phosphorus and lakes Most limiting plant nutrient in lakes Algae blooms = low oxygen and smell 1 lbs P = 300 lbs to 500 lbs algae</p></li><li><p>High growthLow lightLow oxygenImpacts of phosphorus</p></li><li><p>10,000s YEARS IN NATURAL CONDITIONS10s to 100s YEARS UNDER HUMAN INFLUENCESpeeding aging of lakes</p></li><li><p>Tropic State</p></li><li><p>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</p></li><li><p>As phosphorus goes up, algae goes up, and water clarity goes down</p></li><li><p>Secchi DiskSecchi disk is a low-tech way to measure water clarity and determine a lakes tropic state </p></li><li><p>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</p></li><li><p>Sources of phosphorus When it rains, it pollutesThink watersheds!</p></li><li><p>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</p></li><li><p>Impervious surfacesResidential Areas = 50% Impervious</p></li><li><p>Every city lot is waterfront property!</p></li><li><p>StreetsLawnsDrivewaysRoofsSidewalksSources of phosphorus runoffBannerman - Wisconsin DNR</p></li><li><p>Soluble plant PSoil solution PSources of phosphorus runoff from lawns</p></li><li><p>Sources of phosphorus runoff from lawns Runoff from plant material (dissolved) Misapplied fertilizer (dissolved) Runoff from soil solution (dissolved) Attached to eroded soil (particulate)</p></li><li><p>Sources of phosphorus runoff from lawns Runoff from plant material (dissolved) Misapplied fertilizer (dissolved) Runoff from soil solution (dissolved) Attached to eroded soil (particulate)?</p></li><li><p>Phosphorus runoff by land use</p><p>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.</p></li><li><p>Grass clippings Contain 0.13 lbs P / 1000 sq. ft. / year Thats 0.65 lbs P / ave. yard / year</p></li><li><p>Controlling P runoff is package deal</p></li><li><p>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</p></li><li><p>Phosphorus fertilization Apply according to soil test Important when seeding or sodding Rarely needed on est. lawns in Metro Sweep up overspread &amp; spilled material </p></li><li><p>Reading the bag Given in % phosphate by weight Phosphate (P2O5) not phosphorus (P)! P = P2O5 2.29Look for the middle number! N - P - K</p></li><li><p> 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</p></li><li><p> Sample front and back lawn separately Sample randomly, avoid odd areas Mix in plastic bucket send 1 pint to lab</p></li><li><p>Two phosphorus tests used in Minnesota based on soil pH: Bray 1 pH 7.4 Olsen pH &gt; 7.4</p></li><li><p> 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 </p></li><li><p> State phosphorus lawn fertilizer law Local fertilizer ordinances Use vs. Sale regulationThe law and the lawn </p></li><li><p>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</p></li><li><p>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</p></li><li><p>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</p></li><li><p>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.</p></li><li><p>MN lawn fertilizer lawProhibited to apply fertilizer (any type) to impervious surfaces.Examples: Streets, sidewalks, driveways.Started 2002</p></li><li><p>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</p></li><li><p>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</p></li><li><p>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</p></li><li><p>Publication on the new law800-877-6300 to place orders</p></li><li><p>0% P2O5 fertilizers becoming widely available . . . </p></li><li><p> 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 . . .</p></li><li><p> 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 . . .</p></li><li><p>What to advise . . . All lawns - Sweep up, rake up, pick up - Soil test if interested in baseline </p></li><li><p>What to advise . . . Future? practices to increase infiltrationRain garden in Maplewood, MN</p></li><li><p> Spring / Fall messages in the media Web site with resources for citizens, cities, and teachers/students TV weather broadcast / clean water featurewww.cleanwatermn.org</p></li><li><p>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</p></li><li><p>Ron StrussExtension Educator University of Minnesota Extension Service651-215-1950 rstruss@umn.edu</p></li><li><p>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.</p><p>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.</p><p>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 and water, phosphorus exists as phosphate a compound where phosphorus is combined with oxygen or with oxygen and hydrogen.</p><p>The simplest form of phosphate also called orthophosphate is one phosphorus atom surrounded by four oxygen atoms. Its chemical formula is PO4.</p><p>The word phosphorus or symbol P refers to the element but also is used as a general term when a specific chemical form of P is not being designated. Therefore the phosphorus content of a soil can be discussed when in actuality no elemental phosphorus exists in the soil, just phosphorus found in compounds.Relatively large amounts of phosphorus is required by plants. It is considered a macronutrient, and along with nitrogen (N) and potassium (P) is one of the three plant nutrients generally added to soils through fertilizers.</p><p>Main roles for phosphorus in plants is energy transfer and cell division. Adequate phosphorus availability stimulates early growth and hastens maturity. Like in corn, phosphorus deficiency in turf can exhibit itself in purple and yellow leaf color.</p><p>Picture is of a corn plant showing the purple leaf tip color of phosphorus deficiency.But purple or yellow coloration in turf is rare. More often the symptom will be stunted growth, which is not always obvious or easy to detect.Phosphorus can be thought of existing in three pools in the soil. Two pools are shown here, Soil Solution Phosphorus and Active Soil Phosphorus.</p><p>Not shown here is the third pool, Fixed Soil Phosphorus, which as its name indicates, contains phosphorus in forms that are very resistant to breaking down and becoming available to plants. It is not considered when determining the phosphorus fertility of a soil.Soil Solution Phosphorus is phosphorus usually phosphate that is dissolved in soil water.</p><p>Since most phosphorus compounds are not very water soluble, Soil Solution Phosphorus accounts for less than a pound of phosphorus per acre.</p><p>It is the only pool of phosphorus plants can draw from. It is also the only pool which contains phosphorus in a mobile form that can move freely in water solution.</p><p>Active Soil Phosphorus is phosphorus in the solid phase that can readily move into water solution. As plants use phosphorus from soil solution, the concentration of phosphorus in solution drops, causing phosphorus to move from Active Soil Phosphorus to replace it. Think of Active Soil Phosphorus as a bank account from which withdrawals are made when needed. The double arrow indicates an equilibrium between Soil Solution Phosphorus and Active Soil Phosphorus. Active Soil Phosphorus can account for 10s to 100s pounds of phosphorus per acre.</p><p>Depending on soil pH, phosphorus in Active Soil Phosphorus is found as phosphate (PO4) or compounds with aluminum (Al) and calcium (Ca). It also can exist in organic forms of phosphorus. </p><p>Active Soil Phosphorus is tightly adhered to clay particles and does not move unless the soil it attached to moves. Since the vast majority of soil phosphorus is held as Active Soil Phosphorus, the adage Keep soil in place keep phosphorus in place was coined.Soil pH affects the availability of phosphorus to plants. Keeping soil pH between 6.0 pH and 7.0 pH results in the most efficient use of phosphorus.</p><p>Below 6.0 pH, phosphorus becomes tightly bound with aluminum; above 7.0 pH, phosphorus becomes tightly bound with calcium.The need to fertilize the phosphorus is determined by comparing soil tests results to what is know about the phosphorus needs of the plant to be grown. Plants have been grown under different levels of fertilization in research plots to determine what their nutrient requirements are.</p><p>Generally for turf, phosphorus fertilization is recommended when soil tests measure less than 25 parts per million of phosphorus. That is about 50 pounds of phosphorus per acre. Soil tests measure both the Soil Solution Phosphorus and Active Soil Phosphorus pools.</p><p>This level was set by field trials done in 1983. After the establishment year, turf grown on soil containing 27 ppm phosphorus did not show any positive response to additions of phosphorus fertilizer.Phosphorus is the most limiting plant nutrient in lakes. Small increases in available phosphorus can result in dramatic increases in growth of aquatic plants, including free floating algae.</p><p>Rapid growths of algae are called blooms. One pound of phosphorus added to a water system can results in 300 to 500 additional pounds of algae growth.High growth of algae and other aquatic (water) plants have the following impacts:</p><p>1. Lowers the appearance and increases the smell of water.</p><p>2. Interferes with swimming and boating.</p><p>3. Algae and floating plants can block light from getting to bottom dwelling plants, eliminating important fish and bird habitat.</p><p>4. When excessive plant growth dies and settles to the lake bottom, its decomposition ties up oxygen, making it no longer available for fish.Lakes age naturally as they become more enriched with nutrients over time. Over eons, deep crystal clear lakes become marshes and bogs. Without the visitation of another glacier, Minnesota will some day become the Land of 10,000 bogs.</p><p>However, by increasing the rate of nutrient enrichment by human activities, a process that would take 10,000 years can occur in a lifetime. Land distributing activities; cutting timber, farming, construction, have increased the rate of nutrient enrichment of lakes, and increased their rate of aging.</p><p>Lakes are classified according to their topic state. Tropic means nutrition or growth. An oligotrophic lake has low nutrient concentrations and low plant growth. An eutrophic lake is high in nutrient concentration and plant growth. Mesotrophic lakes are between these two status.</p><p>The process of lake becoming enriched with nutrients and progressing towards the eutrophic state is call eutrophication. Once concentration of phosph...</p></li></ul>