phosphorus and phosphorus management. outline − introduction − p sources − p transport −...

Phosphorus and Phosphorus and Phosphorus ManagementPhosphorus Management

Phosphorus and Phosphorus and Phosphorus ManagementPhosphorus Management

OutlineOutline

− IntroductionIntroduction− P SourcesP Sources− P TransportP Transport− Environmental ConcernsEnvironmental Concerns− P ManagementP Management− SummarySummary

OutlineOutline

− IntroductionIntroduction− P-Crop NeedP-Crop Need− P FormsP Forms− P CycleP Cycle

− Reactions in SoilReactions in Soil

(fate of P)(fate of P)− P Buffer CapacityP Buffer Capacity

− P SourcesP Sources− P TransportP Transport− Environmental ConcernsEnvironmental Concerns− P ManagementP Management− SummarySummary

IntroductionIntroduction

P-Crop NeedP-Crop Need

− Plants need P for Plants need P for growthgrowth− ATPATP− DNADNA− RNARNA

− P deficiency: P deficiency: − stunted and spindlystunted and spindly− purplish foliage purplish foliage

(older leaves)(older leaves)

IntroductionIntroduction

P-Crop NeedP-Crop Need

Goal of soil testing Goal of soil testing = determine crop = determine crop needneed

- Examples of - Examples of agronomic soil P tests: agronomic soil P tests: Bray P1, Mehlich III, Bray P1, Mehlich III, OlsenOlsen

IntroductionIntroduction

P-Crop NeedP-Crop Need

Soil test P, ppmSoil test P, ppm

CropCrop OptimumOptimum No No responseresponse

AlfalfaAlfalfa 18-2518-25 >35>35

CornCorn 15-2015-20 >30>30

SoybeanSoybean 10-1510-15 >20>20Medium and fine-textured soils, Bray P-1 test.Medium and fine-textured soils, Bray P-1 test.

IntroductionIntroduction

P FormsP Forms

− Inorganic PInorganic P− Fertilizers, soluble PFertilizers, soluble P

− POPO443-3-, HPO, HPO44

2-2-, H, H22POPO44--

− Immediately availableImmediately available

− Organic POrganic P− Manure, plant/leaf residuesManure, plant/leaf residues

− Inositol phosphates, Inositol phosphates, nucleic acids, nucleic acids, phospholipidsphospholipids

− Slowly available (needs to Slowly available (needs to be mineralized to inorganic be mineralized to inorganic form)form)

AS RELATED TO CROPS, SOILS, AND FERTILIZERS

IntroductionIntroduction

P FormsP Forms

− Soil Test PSoil Test P− estimates plant estimates plant

available Pavailable P− usually Bray P1 (in usually Bray P1 (in

WI)WI)− expressed in ppm P expressed in ppm P

(elemental P, not (elemental P, not PP22OO55))

− Phosphate = PPhosphate = P22OO5 5 (oxide)(oxide)− fertilizer recommendations fertilizer recommendations

and product analysis given and product analysis given in oxide formin oxide form

− conversion factors: conversion factors:

1 lb P = 2.29 lb P1 lb P = 2.29 lb P22OO55

1 lb P1 lb P22OO55 = 0.44 lb P = 0.44 lb P

AS RELATED TO CROPS, SOILS, AND FERTILIZERS

IntroductionIntroduction

P FormsP Forms

− Particulate P (PP)Particulate P (PP)− definition: P bound to eroded sediment or organic definition: P bound to eroded sediment or organic

mattermatter− also called sediment-Palso called sediment-P

− Soluble P (SP) Soluble P (SP) − definition: P dissolved in runoff (working definition: P definition: P dissolved in runoff (working definition: P

that passes through a 0.45 micron filter)that passes through a 0.45 micron filter)− also called dissolved P (DP), dissolved reactive P also called dissolved P (DP), dissolved reactive P

(DRP), and ortho-P(DRP), and ortho-P

− Total P (TP)Total P (TP)− definition: total amount of P, both PP and SP, in soil definition: total amount of P, both PP and SP, in soil

or runoffor runoff

AS RELATED TO WATER QUALITY

IntroductionIntroduction

P FormsP Forms

− P ConcentrationP Concentration− definition: amount of P per volumedefinition: amount of P per volume− expressed as: mg P/L or ppmexpressed as: mg P/L or ppm

− P LoadP Load− definition: total amount of P delivereddefinition: total amount of P delivered− expressed as: mg P/ha (lb P/acre)expressed as: mg P/ha (lb P/acre)

AS RELATED TO WATER QUALITY

IntroductionIntroductionP CycleP Cycle

IntroductionIntroduction

P Reactions in SoilP Reactions in Soil

− Mineralization and Immobilization Mineralization and Immobilization (organic P)(organic P)

Organic P forms H2PO4- Fe, Al, Ca phosphates

Fe3+, Al3+, Ca2+

soluble phosphate

microbes

microbesinsoluble fixed P

Immobilization

Mineralization

IntroductionIntroduction

P Reactions in SoilP Reactions in Soil

− Adsorption and DesorptionAdsorption and Desorption− Clays, Fe and Al oxides, organic matterClays, Fe and Al oxides, organic matter

− Precipitation/DissolutionPrecipitation/Dissolution− Acid soils – Fe, Al, Mn compounds dominateAcid soils – Fe, Al, Mn compounds dominate− Alkaline soils – Ca compounds dominateAlkaline soils – Ca compounds dominate

(inorganic P)(inorganic P)

What happens when fertilizer or manure P is added to What happens when fertilizer or manure P is added to soil?soil?

P is P is quickly quickly

and and strongly strongly bound to bound to

soil soil particles.particles.

IntroductionIntroduction

Buffer CapacityBuffer Capacity

− P buffer capacity (indication of the rate of P buffer capacity (indication of the rate of change of STP with additions or removals)change of STP with additions or removals)

Ave 18 lbs PAve 18 lbs P22OO55/acre to change STP by 1ppm/acre to change STP by 1ppm

((Leikam, 1992Leikam, 1992))

− Time is needed to raise OR lower STPTime is needed to raise OR lower STP

OutlineOutline

− IntroductionIntroduction− P SourcesP Sources

− SoilSoil− PlantsPlants− FertilizersFertilizers

−P TransportP Transport−Environmental ConcernsEnvironmental Concerns−P ManagementP Management−SummarySummary

− ManuresManures− Livestock FeedLivestock Feed− Municipal WasteMunicipal Waste

P SourcesP Sources

SoilSoil

P occurs naturally in soil (but usually in very low P occurs naturally in soil (but usually in very low concentrations) concentrations)

FormForm Concentration (ppm)Concentration (ppm)

TotalTotal 400-1500400-1500

Soil Test P Soil Test P (agronomic)(agronomic)

20-5020-50

Soil SolutionSoil Solution 0.01-0.300.01-0.30

P SourcesP Sources

PlantsPlants

− Vegetation can Vegetation can contribute P to runoff contribute P to runoff − plants release P when plants release P when

tissue is ruptured due to tissue is ruptured due to freezing, thawing, and freezing, thawing, and dryingdrying

P SourcesP Sources

FertilizersFertilizers

− Added to soil to increase fertility for crop Added to soil to increase fertility for crop productionproduction

− Common examples:Common examples: N-PN-P22OO44-K-K22OO− Monoammonium phosphate: NHMonoammonium phosphate: NH44HH22POPO44 11-48-011-48-0− Diammonium phosphate: (NHDiammonium phosphate: (NH44))22HPOHPO44 18-46-018-46-0− Triple superphosphate: Ca(HTriple superphosphate: Ca(H22POPO44))22 0-46-00-46-0

− Easily soluble to runoff water Easily soluble to runoff water (if rain comes shortly after application)(if rain comes shortly after application)

P SourcesP Sources

ManureManure

− Manure contains nutrients for plant growth, including PManure contains nutrients for plant growth, including P

− Manure applications improve physical properties of soilManure applications improve physical properties of soil

− Manure applications can lead to buildup of soil P Manure applications can lead to buildup of soil P

P SourcesP Sources

ManureManure

LivestoLivestockck

--Nitrogen --Nitrogen (N)--(N)--

PhosphaPhosphatete

PotashPotash

SurfaceSurface Incorpor-Incorpor-atedated

(P(P22OO55)) (K(K22O)O)

---Solid------Solid---

---lbs/ton------lbs/ton---

DairyDairy 33 44 33 77

BeefBeef 33 55 55 99

SwineSwine 77 99 66 77

ChickenChicken 2020 2424 3030 2424Note: Manure supplies approximately equal amounts of N and P.

P SourcesP Sources

Livestock FeedLivestock Feed

− Farm animals need Farm animals need adequate protein, adequate protein, energy, and nutritionenergy, and nutrition

− Dietary rations often Dietary rations often contain excess contain excess nutrients, particularly Pnutrients, particularly P

P SourcesP Sources

Industrial and Municipal WasteIndustrial and Municipal Waste

− Water discharged from wastewater treatment Water discharged from wastewater treatment facilitiesfacilities

− Storm water runoff Storm water runoff

− BiosolidsBiosolids

www.milorganite.com

OutlineOutline

− IntroductionIntroduction− P SourcesP Sources− P TransportP Transport

− Runoff and ErosionRunoff and Erosion

−Environmental ConcernsEnvironmental Concerns−P ManagementP Management−SummarySummary

− P LeachingP Leaching

P TransportP Transport

Runoff and ErosionRunoff and Erosion

− RunoffRunoff=movement of water =movement of water across the land’s across the land’s surfacesurface

− ErosionErosion=movement of soil =movement of soil particles by waterparticles by water

Runoff and erosion are Runoff and erosion are SURFACE WATERSURFACE WATER quality problems.quality problems.

P TransportP Transport

LeachingLeaching

− LeachingLeaching

=infiltration of water through soil to groundwater=infiltration of water through soil to groundwater

(low on most Wisconsin soils)(low on most Wisconsin soils)

P leaching is a P leaching is a GROUNDWATERGROUNDWATER quality problemquality problem

P TransportP Transport

LeachingLeaching

Nutrient and Pest Management Program

OutlineOutline

− IntroductionIntroduction− P SourcesP Sources− P TransportP Transport− Environmental Environmental

ConcernsConcerns− EutrophicationEutrophication− Soil Test PSoil Test P

− Point/NonPoint Point/NonPoint PollutionPollution

− Urban/AgriculturalUrban/Agricultural− P Management P Management − SummarySummary

Environmental ConcernsEnvironmental Concerns

EutrophicationEutrophication

What happens when a stream or lake What happens when a stream or lake receives more P than it is used to receives more P than it is used to

receiving?receiving?

− Too little P = land degradationToo little P = land degradation

− Too much P = eutrophicationToo much P = eutrophication

Environmental ConcernsEnvironmental Concerns

EutrophicationEutrophication

P moves from soil to streamP moves from soil to stream

P stimulates algae growthP stimulates algae growth

Too much algae blocks sun, uses oxygenToo much algae blocks sun, uses oxygen

Fish can die, stream health declines = Fish can die, stream health declines =

Odor, limits recreational uses, lowers drinking water Odor, limits recreational uses, lowers drinking water qualityquality

Environmental ConcernsEnvironmental Concerns

Soil Test PSoil Test P

Accumulation of P as a result of inputs exceeding removals

Environmental ConcernsEnvironmental Concerns

Soil Test PSoil Test P

y = 0.01x

R2 = 0.75

0.0

0.5

1.0

1.5

2.0

2.5

3.0

0 50 100 150 200 250

Soil Test P (ppm)

Ave

rag

e ru

no

ff D

RP

(p

pm

)

Natural runoff from April through July on corn plots at Natural runoff from April through July on corn plots at Arlington.Arlington.

As soil test P As soil test P increases, the increases, the amount of P amount of P dissolved in runoff dissolved in runoff also increases.also increases.

Environmental ConcernsEnvironmental Concerns

Soil Test PSoil Test P

N-based nutrient management strategyN-based nutrient management strategy

0

50

100

150

200

N P K

Corn Need 40 t/ a Manure Supply

160

60

120

45

320

lbs/acre

N needs met, N needs met, but as a but as a result, twice result, twice as much P as as much P as needed was needed was applied. applied.

Environmental ConcernsEnvironmental Concerns

Soil Test PSoil Test P

P-based nutrient management strategyP-based nutrient management strategy

0

50

100

150

200

N P K

Corn Need 20 t/ a Manure Supply

160 80 60

45

160

P needs met, but P needs met, but will need will need supplemental N supplemental N AND more acres AND more acres to apply manure. to apply manure.

lbs/acre

Environmental ConcernsEnvironmental Concerns

Point/Nonpoint PollutionPoint/Nonpoint Pollution

− Point source pollution: Identifiable Point source pollution: Identifiable pollution discharge sources. pollution discharge sources.

− Nonpoint source pollution: Diffuse, Nonpoint source pollution: Diffuse, hard-to-identify pollution sources hard-to-identify pollution sources transported by runoff and erosion transported by runoff and erosion from a widespread land area.from a widespread land area.

Environmental ConcernsEnvironmental Concerns

Urban/AgriculturalUrban/Agricultural

− Urban sources of P: Urban sources of P: − lawns: leaves, soil, fertilizer, animal droppings, lawns: leaves, soil, fertilizer, animal droppings,

plantsplants− wastewater wastewater − biosolidsbiosolids

− Agricultural sources of P:Agricultural sources of P:− manuremanure− fertilizerfertilizer− crop tissuecrop tissue− soilsoil

OutlineOutline

− IntroductionIntroduction− P SourcesP Sources− P TransportP Transport− Environmental ConcernsEnvironmental Concerns− P ManagementP Management

− Approaches to Improve P BalanceApproaches to Improve P Balance− Management to Reduce P LossesManagement to Reduce P Losses

− SummarySummary

P Management - Improve P BalanceP Management - Improve P Balance

NPM Program

P Management - Improve P BalanceP Management - Improve P Balance

Follow Soil Test RecommendationsFollow Soil Test Recommendations

− At optimum STP, At optimum STP,

recommended nutrients = anticipated crop recommended nutrients = anticipated crop removalremoval

− Soil test every 3-4 yearsSoil test every 3-4 years

P Management - Improve P BalanceP Management - Improve P Balance

Credit Nutrient SourcesCredit Nutrient Sources

− Credit manure P BEFORE determining Credit manure P BEFORE determining supplemental fertilizer application ratessupplemental fertilizer application rates

− Manure can supply crop nutrients as Manure can supply crop nutrients as effectively as commercial fertilizerseffectively as commercial fertilizers

− Need Need nutrient contentnutrient content and and application rateapplication rate

Lab analysis or book value Calibrate!Lab analysis or book value Calibrate!

P Management - Improve P BalanceP Management - Improve P Balance

Use Starter JudiciouslyUse Starter Judiciously

− Recommendation: for corn Recommendation: for corn band applyband apply starter starter fertilizer if needed (10 lb N, 20 lb Pfertilizer if needed (10 lb N, 20 lb P22OO55, 20 lb K, 20 lb K22O) O)

− On soils in the excessively high range for P, On soils in the excessively high range for P, avoidavoid starter applications in excess of 10-20-20starter applications in excess of 10-20-20

P Management - Improve P BalanceP Management - Improve P Balance

P Management - Improve P BalanceP Management - Improve P Balance

− DairyDairy− know know P contentP content of dietary supplements of dietary supplements− NRC recommends between 0.32 and 0.38%P, NRC recommends between 0.32 and 0.38%P,

depending on milk productiondepending on milk production

− Swine/PoultrySwine/Poultry− improve efficiency improve efficiency

− consider feeding consider feeding HAPHAP corn corn− consider adding consider adding phytasephytase enzyme to feed enzyme to feed

Manage Dietary PManage Dietary PGoal: avoid overfeeding PGoal: avoid overfeeding P

FOLLOW DIETARY P GUIDELINESFOLLOW DIETARY P GUIDELINES

P Management - Improve P BalanceP Management - Improve P Balance

Manage Dietary PManage Dietary P

0

10

20

30

40

50

60

70

80

man

ure

P, l

b/co

w/y

ear

0.35 0.38 0.48 0.55

% P in diet

Phosphorus level in Phosphorus level in the manure is directly the manure is directly related to the level of related to the level of P intake.P intake.

Source: Powell et al, 2001

P Management - Improve P BalanceP Management - Improve P Balance

Manage Dietary PManage Dietary P

0

10

20

30

40

50

60

70

80

Dis

solv

ed P

Lo

ad (

g P

/ha)

June October

0.32% P

0.48% P

Dairy manure applied at 25

ton/a

Source: Ebeling et al, 2002

P Management - Improve P BalanceP Management - Improve P Balance

Manage Dietary PManage Dietary P

0

20

40

60

80

100

120

140

11-N

ov

6-Dec

28-F

eb

31-M

ar

21-A

pr

9-M

ay

19-M

ay

8-Ju

n

29-J

un

Sampling Date

Dis

so

lve

d P

Lo

ad

(g

P/h

a) High P Diet (0.48%)

Low P Diet (0.32%)

Control

One year after One year after manure manure application, the application, the cumulative runoff cumulative runoff dissolved P losses dissolved P losses were significantly were significantly higher from the higher from the plots with high P plots with high P diet manure diet manure compared to the compared to the low P diet manure low P diet manure and control. and control.

Source: Ebeling et al, 2002

P Management - Improve P BalanceP Management - Improve P Balance

Increase land baseIncrease land base

− Ensure all cropland receives manure sometime Ensure all cropland receives manure sometime during the rotationduring the rotation

− Apply manure to rented landApply manure to rented land

− Obtain manure application rights from Obtain manure application rights from neighboring grain farmersneighboring grain farmers

P Management - Reduce P LossP Management - Reduce P Loss

In order for P to reach surface water: In order for P to reach surface water:

need both a SOURCE of P and MOVEMENT of Pneed both a SOURCE of P and MOVEMENT of P

Source TransportP LOSSP LOSS

P Management - Reduce P LossP Management - Reduce P Loss

Identify low risk sitesIdentify low risk sites

− Source and transport – site specific:Source and transport – site specific:

− P Index: P Index: http://wpindex.soils.wisc.eduhttp://wpindex.soils.wisc.edu

− SNAP-Plus: SNAP-Plus: www.snapplus.netwww.snapplus.net

P Management - Reduce P LossP Management - Reduce P Loss

Identify low risk sitesIdentify low risk sites

Total Risk Index (PI) = Total Risk Index (PI) = [Soluble P + Particulate P + Acute P] * total P delivery ratio[Soluble P + Particulate P + Acute P] * total P delivery ratio

Needed for PI calculations:Needed for PI calculations:--management, cropping rotations, tillage, fertilizer and management, cropping rotations, tillage, fertilizer and

manure applications, soil test P, slope, distance to manure applications, soil test P, slope, distance to surface water, etc.surface water, etc.

Field Crop ID:Field Crop ID:Orange=cornOrange=cornGreen=alfalfaGreen=alfalfa

Yellow=oats(alf. Seed)Yellow=oats(alf. Seed)

PI Values:PI Values:Red=>4Red=>4

Orange=3-3.9Orange=3-3.9Blue=2-2.9Blue=2-2.9

Violet=1-1.9Violet=1-1.9

UW Platteville Farm: 2004 Rotation

P Management - Reduce P LossP Management - Reduce P Loss

− Weather predictionsWeather predictions

− Time of yearTime of year

Consider seasonal limitations to manure Consider seasonal limitations to manure applicationsapplications

P Management - Reduce P LossP Management - Reduce P Loss

− Incorporation of Incorporation of broadcast fertilizer broadcast fertilizer with tillagewith tillage

OROR− Subsurface band Subsurface band

placement placement

Incorporate P Incorporate P fertilizerfertilizer

P Management - Reduce P LossP Management - Reduce P Loss

Incorporate manure??Incorporate manure??Runoff Dissolved P LossesRunoff Dissolved P Losses

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

No-till Chisel

No Manure32 ton/ a

Source: Bundy and Andraski, 2001

Runoff Dissolved Pmg/L

Spring Runoff

P Management - Reduce P LossP Management - Reduce P Loss

Incorporate manure??Incorporate manure??Total P Losses Total P Losses

0

300

600

900

1200

1500

No-till Chisel

No Manure32 ton/ a

Spring Runoff

Total P loadg/ha

Source: Bundy and Andraski, 2001

P Management - Reduce P LossP Management - Reduce P Loss

How does manure affect runoff P How does manure affect runoff P losses?losses?Surface Surface

AppliedApplied(not incorporated)(not incorporated)

-acts as a mulch-acts as a mulch-provides -provides surface residue surface residue covercover-decreases -decreases erosionerosion-increases -increases soluble P losses soluble P losses (especially on no-till (especially on no-till or alfalfa in the or alfalfa in the winter)winter)

IncorporatedIncorporated

-increases -increases erosionerosion-decreases -decreases soluble P lossessoluble P losses

Manure applications reduce runoff volumes and soil lossManure applications reduce runoff volumes and soil loss

P Management - Reduce P LossP Management - Reduce P Loss

Use soil conservation practicesUse soil conservation practices− ExamplesExamples

− Changes in land management practicesChanges in land management practices(cover crops, diverse rotations, (cover crops, diverse rotations, conservation conservation tillage**tillage**, contour farming), contour farming)

− Installation of structural devicesInstallation of structural devices(buffer strips, diversions, grade stabilization (buffer strips, diversions, grade stabilization structures, grassed waterways, and terracesstructures, grassed waterways, and terraces

** most widely adopted and easily accomplished** most widely adopted and easily accomplished

P Management - Reduce P LossP Management - Reduce P Loss

− Reduces amount of Reduces amount of runoffrunoff

− Reduces eroded Reduces eroded sedimentsediment

Use soil conservation practicesUse soil conservation practices

SummarySummary

− Soil Testing ensures adequate supplies of Soil Testing ensures adequate supplies of nutrients for crop productionnutrients for crop production

− P Sources = soil, plants, fertilizers, manures, P Sources = soil, plants, fertilizers, manures, livestock feed, industrial and municipal wasteslivestock feed, industrial and municipal wastes

− P Transport occurs through runoff, erosion and P Transport occurs through runoff, erosion and leaching (usually insignificant in WI)leaching (usually insignificant in WI)

SummarySummary

− Eutrophication of surface water is the main Eutrophication of surface water is the main phosphorus pollution issuephosphorus pollution issue

IMPROVE P BALANCEIMPROVE P BALANCE-Follow soil test recommendations-Follow soil test recommendations-Credit manure P-Credit manure P-Use starter only if needed-Use starter only if needed-Reduce P in diet-Reduce P in diet-Increase land base for spreading-Increase land base for spreading

REDUCE P LOSSREDUCE P LOSS-Use PI to determine low risk -Use PI to determine low risk areas areas for manure applicationfor manure application-Watch the weather forecast-Watch the weather forecast-Incorporate P fertilizer-Incorporate P fertilizer-Use soil conservation practices-Use soil conservation practices

Take Home MessageTake Home Message

Keep P in the field!Keep P in the field!

-for crop use-for crop use

-out of surface water-out of surface water