Organic Phosphorous Components of soil organic matter and plant tissue Phosphate sugars Nucleic Acids (DNA/RNA) ATP Phospholipids ATP
Importance Essential Macronutrient Limiting Resource Present in Fertilizers, animal wastes, wastewater Availability can be very limited
Fertility 10 -15% of applied fertilizer phosphorous used by plants 85 – 90% is bound to soil particles or forms insoluble solids =>excess application =>saturation of soil capacity => mobility in the environment -Total soil phosphorous is low -Most of the total is unavailable to plants -Much of soil P forms insoluble solids (limiting to availability)
Acid Soils (Low pH) Aluminum and Iron availability increased at low pH Al(OH) 3 FeOOH Solubility increased Al 3+ Fe 3+ Al(OH) 3 + 3H + = Al 3+ + 3H 2 O example
Aluminum Precipitation at Low pH H 2 PO 4 - (pH 3-6) Al 3+ + H 2 PO 4 - + 2H 2 0 = Al(OH) 2 H 2 PO 4 + 2H + (Insoluble) Al(PO 4 ) H 2 O Variscite Al 3+ + PO 4 -3 = Al(PO 4 ) simplified Form of available P at low pH: H 2 PO 4 - combines with free Al 3+ and Fe 3+
Calcium Binding in Basic Soils CaCO 3 CaCO 3 + 2H 2 (PO 4 ) - = Ca [H 2 (PO 4 )] 2 + CO 3 2- CaHPO 4 Ca 5 (PO 4 ) 3 OH (Apatite mineral) (higher calcium availability) H 2 (PO 4 ) - is the available form of P
Availability and pH Availability and pH Low pH High pH Aluminum and Iron phosphates Calcium Phosphates Formation of insoluble solids
Coatings on Sands and Silicate Clays Fe coating Fe OH H 2 (PO 4 ) -
Organic Matter Organic matter does not typically bind strongly with phosphorus. Organic matter covers fixation sites Organic matter reacts with free Fe and Al Organic matter competes for anion exch. sites Organic Matter tends to increase P availability
-Plant Available -Fe, Al bound -Calcium bound - Fixed on oxides H 2 PO 4 - HPO 4 -2 Al(PO 4 ) H 2 O Ca 3 (PO 4 ) 2 H 2 PO 4 - Inorganic Soil Phosphorous Inorganic (low) Phosphorus is generally removed from solution by soil processes These processes have a finite capacity to retain phosphorus When the capacity is exceeded, phosphorus can become mobile.
Historic flow patterns in the Kissimmee – Okeechobee – Everglades system has been significantly altered, beginning in the late 1800’s. The design was to drain significant areas for agriculture and development and to prevent floodwaters from communities to the south and east. Historic Flow Patterns Okeechobee and the Everglades
"The first and most abiding impression is the utter worthlessness to civilized man, in its present condition, of the entire region." Buckingham Smith 1835 First Survey In 1850, the Swamplands Act Passed Population: 87,445 Transferred 20 million aces to FL for drainage and reclamation
11 miles (17.7 km) of canal south of Lake Okeechobee towards Miami. 1881 Hamilton Disston 50,000 acres drained Okeechobee north to Kissimmee and west to the Gulf of Mexico.
1904 “pestilence-ridden swamp” Empire of the Everglades Broward Elected
1905 Everglades Drainage District Authorized Canals, taxes By 1920, 4 major canal systems linked Okeechobee to the Atlantic,
1928 Belle Glade Hurricane 135 mph winds 20-foot deep floodwaters South of Okeechobee 3000 to 8000 dead
143 miles of levee 45 feet high and 150 feet wide After the storm Hoover Dike 19 water control structures
Hoover Dike (1932) Everglades Agricultural Area (EAA) Perimeter Levee (1954) Water Conservation Areas (management of flow) Former extent of Kissimmee Basin and floodplain To Gulf To Atlantic Drainage
Phosphorus loading to S. Florida Ecosystem Inputs North and South of Okeechobee Dairy/Beef Crop Production Kissimmee Basin
Sugar, Rice, Veg. 700,000 ac EAA Crops: Everglades Agricultural Area
1940’sthousands of acres converted to agricultural production 1959Cuban exiles established sugar plantations 1960sSugar production increased 4-fold Today, sugarcane production contributes two-thirds of the economic production of Everglades agriculture, and uses nearly 80% of the crop land in the EAA Sugar and vegetable production contributes phosphorus to the ecosystem primarily through fertilizers and to a lesser extent through decomposition of plants. EAA 382,000 acres 46% U.S. Palm Beach, Glades, Hendry Sugar
Celery26020014080200000 Endive2001751501251007550250 Escarole 2001751501251007550250 Lettuce (Head)2001751501251007550250 Radish100400000000 Romaine2001751501251007550250 Sugar Cane120100804020000 0 Phosphorus Fertilization (lbs/ac) Low Soil P V. High Soil P
Phosphorus loading to S. Florida Ecosystem Inputs North and South of Okeechobee Dairy/Beef Agriculture Kissimmee Basin
Dairy and Beef Kissimmee drainage basin 12,000 km 2 In 1521 Ponce de Leon brought horses and cattle to Florida, making it the oldest cattle raising state in the country. No other part of our country had cattle until the Pilgrims brought cattle in the early 1600's Florida's ranchers now raise the third largest number of cattle of any state east of the Mississippi (1947)
Phosphorus Solid Manure: 5.5 g / kg total Phosphorus One cow can excrete between 40 and 60 g of phosphorus per day Subject to movement via runoff, stream flow, soil water movement, and groundwater movement
Cattle and Dairy Okeechobee, Highlands, and Glades Counties: 328,000 head (19% of total) Okeechobee County is ranked number one for all cattle in the state
The Kissimmee river alone contributes about 20% of the phosphorus flowing into Lake Okeechobee The Lower Kissimmee River Basin is among largest sources of external phosphorus loading to Lake Okeechobee Kissimmee – Okeechobee - Everglades Okeechobee, in turn, is a source of phosphorus to the Everglades
Surface Water Improvement Management Act: SWIM SWIM Plan priority basins Mandates phosphorus load level of 397 tons/yr Clean Water act: 154.3 tons per year deadline of January 1, 2015 Lake (1987) Target level of 40 ppb in Lake Okeechobee
The Dairy Rule (1987) creating lagoons to capture and contain dairy waste Dairy Buy-Out Program to facilitate removal of animals from dairies not able to comply Works of the District Rule permits are required for all discharges into waterways Implement Best Management Practices (BMPs) buffer areas around places animals congregate, eliminating phosphorus fertilization near tributaries, reducing phosphorus imports in animal feeds, reducing animal density Some Strategies 19 of 45 Dairies Remain
SWIM target: 397 tons Phosphorus Loads to Okeechobee Above Target 2007: 146 ton reduction of P entering Okeechobee Above SWIM target (tons)
Phosphorus concentrations in the Lake remain at about 117 ppb The target level is 40 ppb. 2007: 146 ton reduction of P entering Okeechobee
Internal Loading Decomposition of submerged aquatic vegetation releasing phosphorus back into the water column Dissolution of compounds in sediments which bind and store phosphorus. Two Sources
Phosphorus and Iron Phosphorus has a strong affinity for iron FePO 4 Solid Precipitate Readily incorporates into bottom sediments Internal Loading
Dissolved phosphorus combines with oxidized iron (Fe 3+ ) to create an insoluble compound that becomes buried in lake sediments. If oxygen contents are reduced (anoxic bottom sediments) the Fe 3+ converts to Fe 2+ which solubilizes the compound returning P to water. P released by sediments is taken up by photosynthetic algae faster than it can be returned to the sediments Fe 3+ + PO 4 3- = Fe(PO 4 ) solid (PO 4 )Fe to water 2+ Fe 3+ high oxygen Fe 2+ low oxygen 3- Simplified:
RECOMMENDATION – Control Internal Phosphorus Loading. Phosphorus-rich mud sediments need to be removed from the lake to the maximum extent that is practical, in order to reduce internal phosphorus loading. Unless this internal loading is substantially reduced, it may take as long as 100 years for the lake to respond to watershed phosphorus control programs. Lake Okeechobee Action Plan Developed by the Lake Okeechobee Issue Team December 6, 1999
Sugar, Rice, Veg. 700,000 ac EAA Crops: Everglades Agricultural Area
Florida to Buy Out Sugar Land for Everglades Restoration WTVJ NBC 6 June 25, 2008: WEST PALM BEACH, Florida -- The largest U.S. producer of cane sugar, U.S. Sugar Corp., would close up shop in a $1.75 billion deal to sell its 292 square miles of land to Florida for Everglades restoration, the company president and Florida Governor Charlie Crist said Tuesday. The deal, announced at a news conference at the Arthur R. Marshall Loxahatchee National Wildlife Refuge, allows the state to buy U.S. Sugar's holdings in the Everglades south of Lake Okeechobee, the heart of the wetland ecosystem. 186,000 acres
Organic soils possessing high natural fertility Historically flooded
Under flooded conditions, oxygen levels tend to be low The diffusion of oxygen through water is about 1000 times slower than diffusion through air Water restricts the movement of oxygen Flooded Marsh Organisms?
Aquatic Plants Die Heterotrophic microorganisms decompose tissues Aerobic heterotrophic organisms use oxygen Oxygen becomes depleted in water; it cannot diffuse fast enough to support aerobic heterotrophs Anaerobic heterotrophs become dominant
Anaerobic Heterotrophic Organisms Can use energy stored in complex carbon compounds in the absence of free oxygen The energy is obtained by exchanging electrons with elements other than oxygen. Nitrogen (nitrate) Sulfur (sulfate) Iron (Fe 3+ )
C 6 H 12 O 6 + 3NO 3 - + 3H 2 O = 6HCO 3 - + 3NH 4 + 1796 kJ C 6 H 12 O 6 + 3SO 4 2- + 3H + = 6HCO 3 - + 3HS - 453 kJ C 6 H 12 O 6 + 6O 2 → 6CO 2 + 6H 2 O 2880 kJ Anaerobic respiration is less efficient and produces less energy. Therefore, anaerobic decomposition is much slower than aerobic decomposition.
Flooded Soils additions Losses (CO 2 ) Accumulation of organic matter at the soil surface Organic matter is added to the soil faster than it can be decomposed by microorganisms Organic matter limestone anaerobic decomposition of organic matter is much slower than aerobic decomposition.
Buildup of Organic soils Organic matter decomposes slowly when submerged in water. (anaerobic decomposition) Soils throughout the glades historically have been submerged. (anaerobic conditions) Led to vast amounts of organic matter accumulation, sometimes >10 ft. thick. Organic matter continues to accumulate as long as flooded conditions persist.
EAA Drainage exposes soils to oxygen and decomposition by aerobic heterotrophic organisms which can more efficiently decompose organic matter Drainage
additions Losses (CO 2 ) Aerobic decomposition (much more efficient) Conversion from anaerobic to Drainage Losses of organic matter by decomposition exceed new additions – soils disappear C 6 H 12 O 6 + 6O 2 → 6CO 2 + 6H 2 O
Public Funding Issues Revisited in State’s Buyout of U.S. Sugar South Florida Business Journal - by Paul Brinkmann a bill in the Florida Senate that would require voter approval of any certificates of appreciation (bonds) issued by water districts.
Comprehensive Everglades Restoration Plan restoration, preservation, and protection of the South Florida ecosystem provide for water supply and flood protection recover and sustain those essential hydrological and biological characteristics that defined the original pre-drainage Everglades Restoration of More Natural Flow Regimes interconnected and interrelated wetlands reestablishment of native plant communities Low levels of nutrients