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Phosphorus and Phosphorus Management

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Phosphorus level in the manure is directly related to the level of P intake. ... of surface water is the main phosphorus pollution issue. IMPROVE P BALANCE ... – PowerPoint PPT presentation

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Title: Phosphorus and Phosphorus Management


1
Phosphorus and Phosphorus Management
2
Outline
  • Introduction
  • P Sources
  • P Transport
  • Environmental Concerns
  • P Management
  • Summary

3
Outline
  • Introduction
  • P-Crop Need
  • P Forms
  • P Cycle
  • Reactions in Soil
  • (fate of P)
  • P Buffer Capacity
  • P Sources
  • P Transport
  • Environmental Concerns
  • P Management
  • Summary

4
IntroductionP-Crop Need
  • Plants need P for growth
  • ATP
  • DNA
  • RNA
  • P deficiency
  • stunted and spindly
  • purplish foliage (older leaves)

5
IntroductionP-Crop Need
Goal of soil testing determine crop need -
Examples of agronomic soil P tests Bray P1,
Mehlich III, Olsen
6
IntroductionP-Crop Need
7
IntroductionP Forms
AS RELATED TO CROPS, SOILS, AND FERTILIZERS
  • Inorganic P
  • Fertilizers, soluble P
  • PO43-, HPO42-, H2PO4-
  • Immediately available
  • Organic P
  • Manure, plant/leaf residues
  • Inositol phosphates, nucleic acids, phospholipids
  • Slowly available (needs to be mineralized to
    inorganic form)

8
IntroductionP Forms
AS RELATED TO CROPS, SOILS, AND FERTILIZERS
  • Soil Test P
  • estimates plant available P
  • usually Bray P1 (in WI)
  • expressed in ppm P (elemental P, not P2O5)
  • Phosphate P2O5 (oxide)
  • fertilizer recommendations and product analysis
    given in oxide form
  • conversion factors
  • 1 lb P 2.29 lb P2O5
  • 1 lb P2O5 0.44 lb P

9
IntroductionP Forms
AS RELATED TO WATER QUALITY
  • Particulate P (PP)
  • definition P bound to eroded sediment or organic
    matter
  • also called sediment-P
  • Soluble P (SP)
  • definition P dissolved in runoff (working
    definition P that passes through a 0.45 micron
    filter)
  • also called dissolved P (DP), dissolved reactive
    P (DRP), and ortho-P
  • Total P (TP)
  • definition total amount of P, both PP and SP, in
    soil or runoff

10
IntroductionP Forms
AS RELATED TO WATER QUALITY
  • P Concentration
  • definition amount of P per volume
  • expressed as mg P/L or ppm
  • P Load
  • definition total amount of P delivered
  • expressed as mg P/ha (lb P/acre)

11
IntroductionP Cycle
12
(No Transcript)
13
IntroductionP Reactions in Soil
  • Mineralization and Immobilization (organic P)

Immobilization
Fe3, Al3, Ca2
microbes
Organic P forms
H2PO4-
Fe, Al, Ca phosphates
microbes
insoluble fixed P
soluble phosphate
Mineralization
14
IntroductionP Reactions in Soil
  • Adsorption and Desorption
  • Clays, Fe and Al oxides, organic matter
  • Precipitation/Dissolution
  • Acid soils Fe, Al, Mn compounds dominate
  • Alkaline soils Ca compounds dominate

What happens when fertilizer or manure P is added
to soil?
P is quickly and strongly bound to soil particles.
(inorganic P)
15
IntroductionBuffer Capacity
  • P buffer capacity (indication of the rate of
    change of STP with additions or removals)
  • Ave 18 lbs P2O5/acre to change STP by 1ppm
  • (Leikam, 1992)
  • Time is needed to raise OR lower STP

16
Outline
  • Introduction
  • P Sources
  • Soil
  • Plants
  • Fertilizers
  • Manures
  • Livestock Feed
  • Municipal Waste
  • P Transport
  • Environmental Concerns
  • P Management
  • Summary

17
P SourcesSoil
  • P occurs naturally in soil (but usually in very
    low concentrations)

18
P SourcesPlants
  • Vegetation can contribute P to runoff
  • plants release P when tissue is ruptured due to
    freezing, thawing, and drying

19
P SourcesFertilizers
  • Added to soil to increase fertility for crop
    production
  • Common examples N-P2O4-K2O
  • Monoammonium phosphate NH4H2PO4 11-48-0
  • Diammonium phosphate (NH4)2HPO4 18-46-0
  • Triple superphosphate Ca(H2PO4)2 0-46-0
  • Easily soluble to runoff water
  • (if rain comes shortly after application)

20
P SourcesManure
  • Manure contains nutrients for plant growth,
    including P
  • Manure applications improve physical properties
    of soil
  • Manure applications can lead to buildup of soil P

21
P SourcesManure
Note Manure supplies approximately equal amounts
of N and P.
22
P SourcesLivestock Feed
  • Farm animals need adequate protein, energy, and
    nutrition
  • Dietary rations often contain excess nutrients,
    particularly P

23
P SourcesIndustrial and Municipal Waste
  • Water discharged from wastewater treatment
    facilities
  • Storm water runoff
  • Biosolids

www.milorganite.com
24
Outline
  • Introduction
  • P Sources
  • P Transport
  • Runoff and Erosion
  • P Leaching
  • Environmental Concerns
  • P Management
  • Summary

25
P TransportRunoff and Erosion
  • Runoff
  • movement of water across the lands surface
  • Erosion
  • movement of soil particles by water

Runoff and erosion are SURFACE WATER quality
problems.
26
P TransportLeaching
  • Leaching
  • infiltration of water through soil to
    groundwater
  • (low on most Wisconsin soils)

P leaching is a GROUNDWATER quality problem
27
P TransportLeaching
Nutrient and Pest Management Program
28
Outline
  • Introduction
  • P Sources
  • P Transport
  • Environmental Concerns
  • Eutrophication
  • Soil Test P
  • Point/NonPoint Pollution
  • Urban/Agricultural
  • P Management
  • Summary

29
Environmental ConcernsEutrophication
  • Too little P land degradation
  • Too much P eutrophication

What happens when a stream or lake receives more
P than it is used to receiving?
30
Environmental ConcernsEutrophication
  • P moves from soil to stream
  • P stimulates algae growth
  • Too much algae blocks sun, uses oxygen
  • Fish can die, stream health declines
  • Odor, limits recreational uses, lowers drinking
    water quality

31
Environmental ConcernsSoil Test P
Accumulation of P as a result of inputs exceeding
removals
32
Environmental ConcernsSoil Test P
As soil test P increases, the amount of P
dissolved in runoff also increases.
Natural runoff from April through July on corn
plots at Arlington.
33
Environmental Concerns Soil Test P
  • N-based nutrient management strategy

lbs/acre
N needs met, but as a result, twice as much P as
needed was applied.
160
320
120
60
45
34
Environmental Concerns Soil Test P
  • P-based nutrient management strategy

lbs/acre
P needs met, but will need supplemental N AND
more acres to apply manure.
160
160
80
60
45
35
Environmental ConcernsPoint/Nonpoint Pollution
  • Point source pollution Identifiable pollution
    discharge sources.
  • Nonpoint source pollution Diffuse,
    hard-to-identify pollution sources transported by
    runoff and erosion from a widespread land area.

36
Environmental ConcernsUrban/Agricultural
  • Urban sources of P
  • lawns leaves, soil, fertilizer, animal
    droppings, plants
  • wastewater
  • biosolids
  • Agricultural sources of P
  • manure
  • fertilizer
  • crop tissue
  • soil

37
Outline
  • Introduction
  • P Sources
  • P Transport
  • Environmental Concerns
  • P Management
  • Approaches to Improve P Balance
  • Management to Reduce P Losses
  • Summary

38
P Management - Improve P Balance
NPM Program
39
P Management - Improve P Balance
  • Follow Soil Test Recommendations
  • At optimum STP,
  • recommended nutrients anticipated crop removal
  • Soil test every 3-4 years

40
P Management - Improve P Balance
  • Credit Nutrient Sources
  • Credit manure P BEFORE determining supplemental
    fertilizer application rates
  • Manure can supply crop nutrients as effectively
    as commercial fertilizers
  • Need nutrient content and application rate
  • Lab analysis or book value Calibrate!

41
P Management - Improve P Balance
  • Use Starter Judiciously
  • Recommendation for corn band apply starter
    fertilizer if needed (10 lb N, 20 lb P2O5, 20 lb
    K2O)
  • On soils in the excessively high range for P,
    avoid starter applications in excess of 10-20-20

42
P Management - Improve P Balance
43
P Management - Improve P Balance
Manage Dietary P Goal avoid overfeeding P FOLLOW
DIETARY P GUIDELINES
  • Dairy
  • know P content of dietary supplements
  • NRC recommends between 0.32 and 0.38P, depending
    on milk production
  • Swine/Poultry
  • improve efficiency
  • consider feeding HAP corn
  • consider adding phytase enzyme to feed

44
P Management - Improve P Balance
  • Manage Dietary P

Phosphorus level in the manure is directly
related to the level of P intake.
P in diet
Source Powell et al, 2001
45
P Management - Improve P Balance
  • Manage Dietary P

Dairy manure applied at 25 ton/a
Source Ebeling et al, 2002
46
P Management - Improve P Balance
  • Manage Dietary P

One year after manure application, the cumulative
runoff dissolved P losses were significantly
higher from the plots with high P diet manure
compared to the low P diet manure and control.
Source Ebeling et al, 2002
47
P Management - Improve P Balance
  • Increase land base
  • Ensure all cropland receives manure sometime
    during the rotation
  • Apply manure to rented land
  • Obtain manure application rights from neighboring
    grain farmers

48
P Management - Reduce P Loss
  • In order for P to reach surface water
  • need both a SOURCE of P and MOVEMENT of P

49
P Management - Reduce P Loss
  • Identify low risk sites
  • Source and transport site specific
  • P Index http//wpindex.soils.wisc.edu
  • SNAP-Plus www.snapplus.net

50
P Management - Reduce P Loss
  • Identify low risk sites
  • Total Risk Index (PI)
  • Soluble P Particulate P Acute P total P
    delivery ratio
  • Needed for PI calculations
  • -management, cropping rotations, tillage,
    fertilizer and manure applications, soil test P,
    slope, distance to surface water, etc.

51
Field Crop ID Orangecorn Greenalfalfa Yellowoa
ts(alf. Seed)
PI Values Redgt4 Orange3-3.9 Blue2-2.9 Violet1
-1.9
UW Platteville Farm 2004 Rotation
52
P Management - Reduce P Loss
  • Consider seasonal limitations to manure
    applications
  • Weather predictions
  • Time of year

53
P Management - Reduce P Loss
Incorporate P fertilizer
  • Incorporation of broadcast fertilizer with
    tillage
  • OR
  • Subsurface band placement

54
P Management - Reduce P Loss
  • Incorporate manure??
  • Runoff Dissolved P Losses

Spring Runoff
Runoff Dissolved P mg/L
Source Bundy and Andraski, 2001
55
P Management - Reduce P Loss
  • Incorporate manure??
  • Total P Losses

Spring Runoff
Total P load g/ha
Source Bundy and Andraski, 2001
56
P Management - Reduce P Loss
How does manure affect runoff P losses?
Surface Applied (not incorporated) -acts as a
mulch -provides surface residue cover -decreases
erosion -increases soluble P losses (especially
on no-till or alfalfa in the winter)
Incorporated -increases erosion -decreases
soluble P losses
Manure applications reduce runoff volumes and
soil loss
57
P Management - Reduce P Loss
  • Use soil conservation practices
  • Examples
  • Changes in land management practices
  • (cover crops, diverse rotations, conservation
    tillage, contour farming)
  • Installation of structural devices
  • (buffer strips, diversions, grade stabilization
    structures, grassed waterways, and terraces
  • most widely adopted and easily accomplished

58
P Management - Reduce P Loss
Use soil conservation practices
  • Reduces amount of runoff
  • Reduces eroded sediment

59
Summary
  • Soil Testing ensures adequate supplies of
    nutrients for crop production
  • P Sources soil, plants, fertilizers, manures,
    livestock feed, industrial and municipal wastes
  • P Transport occurs through runoff, erosion and
    leaching (usually insignificant in WI)

60
Summary
  • Eutrophication of surface water is the main
    phosphorus pollution issue

IMPROVE P BALANCE -Follow soil test
recommendations -Credit manure P -Use starter
only if needed -Reduce P in diet -Increase land
base for spreading
REDUCE P LOSS -Use PI to determine low risk areas
for manure application -Watch the weather
forecast -Incorporate P fertilizer -Use soil
conservation practices
61
Take Home Message
  • Keep P in the field!
  • -for crop use
  • -out of surface water
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