PHOSPHORUS CYCLE

1
PHOSPHORUS CYCLE
?Click a Pool to Begin Tour
PLANT and ANIMAL RESIDUES
HUMAN and ANIMAL CONSUMPTION
PLANT UPTAKE as H2PO4- or HPO42-
HUMAN and ANIMAL EXCREMENT(50 of P in phytic
acid form)
Microbial Decomposition
MICROBIAL SINK
Mineralization
Immobilization
Aided by
Mycorrhiza
SOIL
WIND EROSION
MINERALFERTILIZER
INORGANIC P
ORGANIC P
Non-Labile
Labile
Soil Solution

• Humic acid
• Inositol phosphates
• Phospholipids
• Phosphate sugars
• Nucleic acids

• Specific adsorption to Fe, Al, Mn oxides and
  broken clay edges
• Precipitation of Ca or Mg-P at pHgt7
• Precipitation of Fe, Al, or Mn-P at pHlt5

• Weakly sorbed phosphates
• Newly-precipitated Fe, Al, or Mn-P in acid soils
• Newly precipitated Ca or Mg-P in alkaline soils

• Phosphate released from labile pool or added via
  fertilizer

SURFACE RUNOFF
Weathering
Eutrophication

• ROCKBOUND
• Apatite
• Fluorapatite
• Chlorapatite
• Hydroxlapatite

Eutrophication
WATERBODIES and SEDIMENTS
LEACHING
By Damon Wright, 2000 Clyde Alsup and Michelle
Armstrong, 1998 Asrat Shaiferaw, 1994 and Jerry
Speir, 1996
MAIN CYCLE
MORE INFO
2
PHOSPHORUS CYCLE
PLANT and ANIMAL RESIDUES
PLANT UPTAKE as H2PO4- or HPO42-
HUMAN and ANIMAL EXCREMENT(50 of P in phytic
acid form)
Microbial Decomposition
MICROBIAL SINK
Mineralization
Immobilization
Aided by
Mycorrhiza
SOIL
WIND EROSION
MINERALFERTILIZER
INORGANIC P
ORGANIC P
Non-Labile
Labile
Soil Solution

• Humic acid
• Inositol phosphates
• Phospholipids
• Phosphate sugars
• Nucleic acids

• Specific adsorption to Fe, Al, Mn oxides and
  broken clay edges
• Precipitation of Ca or Mg-P at pHgt7
• Precipitation of Fe, Al, or Mn-P at pHlt5

• Weakly sorbed phosphates
• Newly-precipitated Fe, Al, or Mn-P in acid soils
• Newly precipitated Ca or Mg-P in alkaline soils

• Phosphate released from labile pool or added via
  fertilizer

SURFACE RUNOFF
Weathering

• ROCKBOUND
• Apatite
• Fluorapatite
• Chlorapatite
• Hydroxlapatite

LEACHING
MAIN CYCLE
MORE INFO
3
PHOSPHORUS CYCLE
SOIL
MINERALFERTILIZER
INORGANIC P
ORGANIC P
Non-Labile
Labile
Soil Solution

• Humic acid
• Inositol phosphates
• Phospholipids
• Phosphate sugars
• Nucleic acids

• Specific adsorption to Fe, Al, Mn oxides and
  broken clay edges
• Precipitation of Ca or Mg-P at pHgt7
• Precipitation of Fe, Al, or Mn-P at pHlt5

• Weakly sorbed phosphates
• Newly-precipitated Fe, Al, or Mn-P in acid soils
• Newly precipitated Ca or Mg-P in alkaline soils

• Phosphate released from labile pool or added via
  fertilizer

Weathering

• ROCKBOUND
• Apatite
• Fluorapatite
• Chlorapatite
• Hydroxlapatite

MAIN CYCLE
MORE INFO
4
PHOSPHORUS CYCLE
SOIL
MINERALFERTILIZER
INORGANIC P
ORGANIC P
Non-Labile
Labile
Soil Solution

• Humic acid
• Inositol phosphates
• Phospholipids
• Phosphate sugars
• Nucleic acids

• Specific adsorption to Fe, Al, Mn oxides and
  broken clay edges
• Precipitation of Ca or Mg-P at pHgt7
• Precipitation of Fe, Al, or Mn-P at pHlt5

• Weakly sorbed phosphates
• Newly-precipitated Fe, Al, or Mn-P in acid soils
• Newly precipitated Ca or Mg-P in alkaline soils

• Phosphate released from labile pool or added via
  fertilizer

• ROCKBOUND
• Apatite
• Fluorapatite
• Chlorapatite
• Hydroxlapatite

MAIN CYCLE
MORE INFO
5
PHOSPHORUS CYCLE
HUMAN and ANIMAL CONSUMPTION
HUMAN and ANIMAL EXCREMENT(50 of P in phytic
acid form)
SOIL
INORGANIC P
ORGANIC P
Non-Labile
Labile
Soil Solution

• Humic acid
• Inositol phosphates
• Phospholipids
• Phosphate sugars
• Nucleic acids

• Specific adsorption to Fe, Al, Mn oxides and
  broken clay edges
• Precipitation of Ca or Mg-P at pHgt7
• Precipitation of Fe, Al, or Mn-P at pHlt5

• Weakly sorbed phosphates
• Newly-precipitated Fe, Al, or Mn-P in acid soils
• Newly precipitated Ca or Mg-P in alkaline soils

• Phosphate released from labile pool or added via
  fertilizer

MAIN CYCLE
MORE INFO
6
PHOSPHORUS CYCLE
HUMAN and ANIMAL CONSUMPTION
PLANT and ANIMAL RESIDUES
PLANT UPTAKE as H2PO4- or HPO42-
HUMAN and ANIMAL EXCREMENT(50 of P in phytic
acid form)
MAIN CYCLE
MORE INFO
7
PHOSPHORUS CYCLE
PLANT and ANIMAL RESIDUES
HUMAN and ANIMAL CONSUMPTION
PLANT UPTAKE as H2PO4- or HPO42-
Aided by
Mycorrhiza
SOIL
INORGANIC P
ORGANIC P
Non-Labile
Labile
Soil Solution

• Humic acid
• Inositol phosphates
• Phospholipids
• Phosphate sugars
• Nucleic acids

• Specific adsorption to Fe, Al, Mn oxides and
  broken clay edges
• Precipitation of Ca or Mg-P at pHgt7
• Precipitation of Fe, Al, or Mn-P at pHlt5

• Weakly sorbed phosphates
• Newly-precipitated Fe, Al, or Mn-P in acid soils
• Newly precipitated Ca or Mg-P in alkaline soils

• Phosphate released from labile pool or added via
  fertilizer

MAIN CYCLE
MORE INFO
8
PHOSPHORUS CYCLE
PLANT and ANIMAL RESIDUES
HUMAN and ANIMAL CONSUMPTION
PLANT UPTAKE as H2PO4- or HPO42-
Microbial Decomposition
SOIL
INORGANIC P
ORGANIC P
Non-Labile
Labile
Soil Solution

• Humic acid
• Inositol phosphates
• Phospholipids
• Phosphate sugars
• Nucleic acids

• Specific adsorption to Fe, Al, Mn oxides and
  broken clay edges
• Precipitation of Ca or Mg-P at pHgt7
• Precipitation of Fe, Al, or Mn-P at pHlt5

• Weakly sorbed phosphates
• Newly-precipitated Fe, Al, or Mn-P in acid soils
• Newly precipitated Ca or Mg-P in alkaline soils

• Phosphate released from labile pool or added via
  fertilizer

MAIN CYCLE
MORE INFO
9
PHOSPHORUS CYCLE
MICROBIAL SINK
Mineralization
Immobilization
SOIL
INORGANIC P
ORGANIC P
Non-Labile
Labile
Soil Solution

• Humic acid
• Inositol phosphates
• Phospholipids
• Phosphate sugars
• Nucleic acids

• Specific adsorption to Fe, Al, Mn oxides and
  broken clay edges
• Precipitation of Ca or Mg-P at pHgt7
• Precipitation of Fe, Al, or Mn-P at pHlt5

• Weakly sorbed phosphates
• Newly-precipitated Fe, Al, or Mn-P in acid soils
• Newly precipitated Ca or Mg-P in alkaline soils

• Phosphate released from labile pool or added via
  fertilizer

MAIN CYCLE
MORE INFO
10
PHOSPHORUS CYCLE
WIND EROSION
SOIL
INORGANIC P
ORGANIC P
Non-Labile
Labile
Soil Solution

• Humic acid
• Inositol phosphates
• Phospholipids
• Phosphate sugars
• Nucleic acids

• Specific adsorption to Fe, Al, Mn oxides and
  broken clay edges
• Precipitation of Ca or Mg-P at pHgt7
• Precipitation of Fe, Al, or Mn-P at pHlt5

• Weakly sorbed phosphates
• Newly-precipitated Fe, Al, or Mn-P in acid soils
• Newly precipitated Ca or Mg-P in alkaline soils

• Phosphate released from labile pool or added via
  fertilizer

WATERBODIES and SEDIMENTS
MAIN CYCLE
MORE INFO
11
PHOSPHORUS CYCLE
SOIL
INORGANIC P
ORGANIC P
Non-Labile
Labile
Soil Solution

• Humic acid
• Inositol phosphates
• Phospholipids
• Phosphate sugars
• Nucleic acids

• Specific adsorption to Fe, Al, Mn oxides and
  broken clay edges
• Precipitation of Ca or Mg-P at pHgt7
• Precipitation of Fe, Al, or Mn-P at pHlt5

• Weakly sorbed phosphates
• Newly-precipitated Fe, Al, or Mn-P in acid soils
• Newly precipitated Ca or Mg-P in alkaline soils

SURFACE RUNOFF

• Phosphate released from labile pool or added via
  fertilizer

Eutrophication
WATERBODIES and SEDIMENTS
MAIN CYCLE
MORE INFO
12
PHOSPHORUS CYCLE
WIND EROSION
SURFACE RUNOFF
Eutrophication
Eutrophication
WATERBODIES and SEDIMENTS
LEACHING
MAIN CYCLE
MORE INFO
13
PHOSPHORUS CYCLE
SOIL
INORGANIC P
ORGANIC P
Non-Labile
Labile
Soil Solution

• Humic acid
• Inositol phosphates
• Phospholipids
• Phosphate sugars
• Nucleic acids

• Specific adsorption to Fe, Al, Mn oxides and
  broken clay edges
• Precipitation of Ca or Mg-P at pHgt7
• Precipitation of Fe, Al, or Mn-P at pHlt5

• Weakly sorbed phosphates
• Newly-precipitated Fe, Al, or Mn-P in acid soils
• Newly precipitated Ca or Mg-P in alkaline soils

• Phosphate released from labile pool or added via
  fertilizer

Eutrophication
WATERBODIES and SEDIMENTS
LEACHING
MAIN CYCLE
MORE INFO
14
PHOSPHORUS CYCLE
?Click a Pool to Search
Web Links
PLANT and ANIMAL RESIDUES
HUMAN and ANIMAL CONSUMPTION
PLANT UPTAKE as H2PO4- or HPO42-
HUMAN and ANIMAL EXCREMENT(50 of P in phytic
acid form)
Microbial Decomposition
MICROBIAL SINK
Mineralization
Immobilization
Land Application
SOIL
WIND EROSION
MINERALFERTILIZER
INORGANIC P
ORGANIC P
Non-Labile
Labile
Soil Solution

• Humic acid
• Inositol phosphates
• Phospholipids
• Phosphate sugars
• Nucleic acids

• Specific adsorption to Fe, Al, Mn oxides and
  broken clay edges
• Precipitation of Ca or Mg-P at pHgt7
• Precipitation of Fe, Al, or Mn-P at pHlt5

• Weakly sorbed phosphates
• Newly-precipitated Fe, Al, or Mn-P in acid soils
• Newly precipitated Ca or Mg-P in alkaline soils

• Phosphate released from labile pool or added via
  fertilizer

SURFACE RUNOFF

• ROCKBOUND
• Apatite
• Fluorapatite
• Chlorapatite
• Hydroxlapatite

WATERBODIES and SEDIMENTS
LEACHING
By Damon Wright, 2000 Clyde Alsup and Michelle
Armstrong, 1998 Asrat Shaiferaw, 1994 and Jerry
Speir, 1996
START AGAIN
MORE INFO
15
Additional Information on Phosphorus
BACK TO MAIN CYCLE

• Form taken up by plant H2PO4-, HPO4
• Mobility in soil None roots must come in
  direct contact with orthophosphate P
• Mobility in plant Yes
• Deficiency symptoms Lower leaves with purple
  leaf margins
• Deficiency pH range lt5.5 and gt7.0
• Toxicity symptoms None
• Toxicity pH range Non toxic (optimum
  availability pH 6.0-6.5)
• Role in plant growth Important component of
  phospholipids and nucleic acids (DNA and RNA)
  
• Role in microbial growth Accumulation and
  release of energy during cellular metabolism
• Concentration in plants 1,000 5,000 ppm (0.1
  0.5)
• Effect of pH on availability H2PO4- at pH lt 7.2
• HPO4 at pH gt 7.2
• Interactions with other P x N, P x Zn at high
  pH, in anion nutrients exchange P
  displaces S, K by mass action displaces Al
  inducing P deficiency (pHlt6.0)

MORE INFO
16
Additional Information on Phosphorus (Cont.)
BACK TO MAIN CYCLE

• P fertilizer sources Rock phosphate, phosphoric
  acid, Ca orthophosphates, ammoniumphosphates,
  ammonium poly-phosphates, nitric phosphates,
  K phosphates, microbial fertilizers
  (phosphobacterins) increase P uptake
• Additional categories
• Mineralization/ CP ratio of lt 200 net
  mineralization of immobilization organic P
  CP ratio of 200-300 no gain/loss of
  inorganic P CP ratio of gt300 net
  immobilization of inorganic P
• P fixation Formation of insoluble Ca, Al, and
  Fe phosphates
• Al(OH)3 H2PO4- ? Al(OH)2HPO4
• (Soluble) (Insoluble)
• Organic P sources Inositol phosphate (Esters of
  orthophosphoric acid), phospholipids, nucleic
  acids, phosphate sugars
• Inorganic P sources Apatite and Ca phosphate
  (unweathered soils) and Fe and Al sinks from P
  fixation (weathered soils)
• Waste Poultry litter (3.0 to 5.0), steel slag
  (3.5), electric coal ash (lt1.0)

MORE INFO
17
Additional Information on Phosphorus (Cont.)
BACK TO MAIN CYCLE

• Total P levels in soil 50 1500 mg/kg
• Solution concentration range lt 0.01 to 1.0 ppm
• Applied fertilizer lt 30 recovered in plants,
  more P must be added than removed by crops
• References
• Alexander, M., 1977. Introduction to Soil
  Microbiology. 2nd Edition. John Wiley and Sons,
  NY.
• Brady, N.C., 1990. The Nature and Properties of
  Soils. 10th Edition. Macmillan Publishing Co.,
  NY.
• Brigham Young University. 1997. The Phosphorus
  Cycle. http//ucs.byu.edu/bioag/aghort/214pres/geo
  chem.htm
• Harrison, A.F., 1987. Soil Organic Phosphorus. A
  Review of World Literature. C.A.B. p.39.
• Pierre, W.H., 1948. The Phosphorus Cycle and
  Soil Fertility. J. Amer. Soc. of Agron.,
  401-14.
• Pierzynski, G.M., Sims, J.T., and Vance, G.F.,
  1994. Soil and Environmental Quality. Lewis
  Publishers, FL.
• Stewart, J.W.B., and Sharpley, A.N., 1987.
  Controls on Dynamics of Soil and Fertilizer
  Phosphorus and Sulfur in Soil Fertility and
  Organic Matter as Critical Components of
  Production Systems, SSSA Spec. Pub. No.19,
  101-121.
• Tiessen, H., 1995. Phosphorus in the Global
  Environment Transfers, Cycles and Management.
  John Wiley and Sons, NY.
• Tisdale, S.L., Nelson, W.L., Beaton, J.D. and
  Havlin, J.L., 1993. Soil Fertility and
  Fertilizers. Macmillan Publishing Co., NY.