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