Supercharging your P fertilizer – Does it Work? Cynthia Grant

Supercharging your P fertilizer – Does it
Work?
Cynthia Grant,
[email protected]
Phosphorus
• Phosphorus is critical for crop growth
– Structural component of nucleotides, nucleic
acids and phospholipids.
– Essential for all energy reactions
– Needed for all growth processes
– Promotes root development, tillering, early
flowering, seed production, and uniform
ripening.
• P fertilizer is a major input for crop production
on the Canadian prairies
• Low P recovery is a major economic and
environmental concern
How Much Phosphorus is Needed by a Crop?
• A 45 bu/acre spring
wheat crop removes
about 24 lb P2O5 per
acre
– About 10 lb more taken up
but recycled in residue
– Total of about 34 lb needed
for growth
– 40 bu/acre canola removes
38 and needs around 58 lb
for growth
Without an adequate P supply,
crop yield will be reduced
-input and off-take should be
balanced over time to avoid
excess or depletion
-not all crop requirement has
to come from fertilizer in each
year
Plants Access P from Soil Solution
Fertilizer additions make up
the difference between crop
demand and soil supply
Soil solution
phosphorus
HPO4-2
H2PO4-2
Products and practices that attempt to improve
P use efficiency
• Banding P near the seed
• Use of more crop available forms
– Fluids versus dry
– Orthophosphates versus polyphosphates
• Reduce soil reactions
– Avail
• Release P gradually to match plant uptake
– Coated MAP
• Fungi that mobilize P in rhizosphere
– Provide Penicillium bilaii
• Fungi that improve plant access to P
– Mycorrhizae
5
How efficiently is P fertilizer used in wheat
systems on the Canadian prairies?
• It is estimated the P use efficiency in the year
of application is generally less than 30%
• What happens to the other 70%?
– Lost by run-off or erosion?
– Converted to other forms of varying solubility?
– Incorporated into the soil organic matter or microbial
biomass?
– Used by subsequent crops?
• Can we use our P fertilizers more efficiently?
On a long-term basis, crop removal and replacement of P
seem to be relatively well-balanced
Manitoba
1965-2006
140,000
100,000
P Removed
80,000
Indicates about 80%
recovery over time
60,000
40,000
P Added
20,000
20
05
20
00
19
95
19
90
19
85
19
80
19
75
19
70
0
19
65
P2O5 (tonnes)
120,000
Timing of supply is important for crop yield response
Source: Johnston 2006
Soil P Reactions Reduce P Availability
Plant Uptake
Phosphate
Fertilizer
Soil
Solution P
Mineral
Surfaces
Lower
Availability
Primary
Minerals
(Apatite)
Secondary
Ca and Mg or
Fe and Al
phosphates
Principles of Phosphorus Nutrition that Affect
Fertilizer Management Choices
• Soil will supply P to the crop
– Fertilizer “tops up” soil supply for optimum yield
– P availability varies with environmental conditions
• P is needed early in growth
– Plants must have adequate supply in first 3-6 weeks
– Soil supply may be too low early in the season
– Need to apply starter at or before seeding
• P is not very mobile
– Ties up with Ca, Mg, Al and Fe
– Doesn’t move far in the soil
– Roots must intercept P since P won’t move to roots
Phosphorus is Relatively Immobile in the Soil
Has important effect
on P management
decisions
Phosphorus Should be Banded
• Banding slows tie-up of P in soil
– Having ammonium N in the band slows reactions further
– MAP, DAP and APP are effective P sources because they
contain ammonium
• Adding urea to MAP bands increases fertilizer P
uptake when fertilizer is banded away from seed
– However, excess N can delay P uptake due to band toxicity
Phosphorus Should be Banded
• Some plant roots proliferate in bands
• Ammonium in the band may also increase root
proliferation
• Uptake increases with P concentration and
rooting
– Fertilizer bands provide high concentration
– More roots in the band increase uptake
Banding P Near the Seed-Row Ensures that Roots Will
Contact the P Granule Early in Growth
Broadcast
Banded
At 25 Kg P2O5/Ha and 18 cm row
spacing have a granule every 2.3
cm (11-55-0)
The large difference between banded and broadcast
applications is POSITION
Courtesy Geza Racz
Banding P Near Seed is Most Important With
• Low soil P levels
• Restricted rooting
– Compaction
– Tillage pans
• Cool soil conditions
– Solubility, mobility, rooting
– Early seeding
Fall band 70-30-10-10 on whole field
+10 lb/ac Seed
row P2O5
No starter P
Pop-Up Effect from Seed Row P
Photo: Aaron Baldwin, Cargill
Banding Reduces the Rate of P Needed
Grain Yield
(T/ha)
3.0
20 band was as good
as 80 broadcast
Broadcast
Banded
2.5
2.0
1.5
1.0
0
10
20
40
Phosphate (kg/ha)
Westco Training Manual
80
Low P Mobility Limits How Much You Can Reduce P
Application Rates
• Must have a high enough rate that each
seedling can reach granule (or droplet)
during early growth
• Reducing rate below about 15-20 lb/acre
may restrict availability
• Distribution is affected by row spacing and
band width
– Greater the seed-bed utilization, the wider
apart the granules are spaced
– May need higher rate with higher seed-bed
utilization
Dry Fertilizer Material
Wheat - 7” rows, 5 lb/a P2O5
10 lb/a MAP fertilizer
7.6” between MAP particles
Wheat - 7” rows, 10 lb/a P2O5
19 lb/a MAP fertilizer
3.8” between MAP particles
Dry Fertilizer Material
Wheat - 7” rows, 15 lb/a P2O5
29 lb/a MAP fertilizer
2.5” between MAP particles
Wheat - 7” rows, 20 lb/a P2O5
38 lb/a MAP fertilizer
1.9” between MAP particles
Liquid Fertilizer Material
Wheat – 7” rows, 5 lb/a P2O5
1.25 gallons/acre 10-34-0
11.2” between drops of fertilizer
Wheat – 7” rows, 10 lb/a P2O5
2.5 gallons/acre 10-34-0
5.9” between drops of fertilizer
Liquid Fertilizer Material
Wheat – 7” rows, 15 lb/a P2O5
3.75 gallons/acre 10-34-0
3.7” between drops of fertilizer
Wheat – 7” rows, 20 lb/a P2O5
5.0 gallons/acre 10-34-0
2.8” between drops of fertilizer
Can different formulations improve P
availability?
• Monoammonium phosphate is the standard
fertilizer source for the prairies
– Ammonium in formulation enhances efficiency
• Ammonium polyphosphate is standard fluid form
• Other novel formulations include:
– Fluid orthophosphates such as Alpine
– Avail additive
– Polymer coated MAP
Fluids Versus Dry
• Under highly calcareous conditions in
Australia, fluid forms of P are more available
than dry
– Water moving toward granule carries Ca
– Ca precipitates P and leads to small reaction
zone
– Fluid forms increase reaction zone and allow
greater root uptake
• Similar benefit has not shown up in tests in
Manitoba
There was no difference between dry MAP and fluid APP in
wheat yield over three years at two sites near Brandon
• Similar results in
previous studies by
Racz and in later
studies on wheat and
soybean
• Soils are much less
calcareous than the
70% calcium carbonate
in the Australian trials
Orthophosphates versus Polyphosphates
• Polyphosphates are chains of
orthophosphates
• Most polyphosphate fertilizers
still have 40-60% of the
phosphate in the
orthophosphate form
• Polyphosphate converts to
orthophosphate in soils rapidly
– Half usually is converted
within a week,
– Conversion may be slower if
soils are cool and dry
• Generally no difference in
effectiveness under field
conditions
– http://www.extension.umn.edu/distribution/
cropsystems/DC6288.html
In studies by Tom Jensen at Brandon, 10-34-0 and MAP performed
as well or better than enhanced P products (Average of 8, 16 and 32
kg ha-1 phosphate rates)
a
42
41.2
b
41
ns
Grain yield, bu/acre
40
39.2
39
38.2
38
38.5
38.1
38.0
37.2
37
35.7
36
35
34
33
32
10-34-0
Simplot 725-6-4
MAP or 11- Omex 10-34- Alpine 6-22-4 Alpine 6-24-6
52-0
0 plus TPA
AVAIL
No AVAIL
Some Enhanced Efficiency P Fertilizers Being Evaluated
•
Avail
–
–
–
–
–
Maleic Itaconic Copolymer
Similar technology to Nutrisphere
Complexes Ca, Mg, Fe and Al
Reduces fixation of P
Limited data under prairie conditions
In studies by Tom Jensen at Brandon, yield was similar with MAP
alone or treated with Avail
a
42
b
41.2
ns
41
Grain yield, bu/acre
40
39.2
39
38.2
38
38.5
38.1
38.0
37.2
37
35.7
36
35
34
33
32
10-34-0
Simplot 725-6-4
MAP or 11- Omex 10-34- Alpine 6-22-4 Alpine 6-24-6
52-0
0 plus TPA
AVAIL
No AVAIL
In wheat on the prairies, yield was similar if
MAP was applied with or without Avail
34
Grain yield, bu/acre
32
- Avail
+ Avail
30
28
26
24
22
0
10
20
30
Wheat (6 site-years) Phophorus rate, lb P2O5/acre
40
Karamanos
Application of Avail-treated MAP produced the same
potato yield as side-banded MAP
Portage and Carberry 2007 to 2009
Potato Yield (cwt/acre)
420
abc
410
400
e
390
380
370
360
350
Gaia Consulting
f
ab
bc
de
Control
Sideband 20
Sideband 40
Sideband 80
Avail 40
Broadcast 40
Avail did not improve grain yield over MAP over three years at
two sites near Brandon
• No difference among
treatments
• All products performed
the same if banded
Coated Enhanced Efficiency P Fertilizer is Being Evaluated
•
Polymer coated monoammonium phosphate
–
–
–
–
–
Same technology as ESN
MAP is gradually released into soil solution
Matching release to crop uptake should reduce
fixation
Can also reduce risk of seedling damage
Limited testing so far
Neither the coated MAP nor the Avail improved grain yield over
MAP or APP over three years at two sites near Brandon
• No difference among
treatments
• All products performed
the same if banded
Novel formulations have not shown yield
benefit in most independent studies
• Fluids, MAP, orthophosphate and polyphosphates,
Avail-treated and coated products performs similarly
• Important to band an adequate amount near seed-row
• Ensure P is available early in the growing season
• Balance P rate with removal over time to avoid
depletion
34
What about the microbial products
• Two major products sold in western Canada
• Provide (Jumpstart and part of Tagteam)
• Mycorrhizal inoculants
35
Provide is a microbial inoculant
• Penicillium bilaii (also classified as P. bilaji and P.
bilaiae) is a fungi that colonizes the rhizosphere
• Effective in solubilizing phosphorus (P) under
controlled conditions
• Under field conditions, results have been mixed
36
On P responsive sites with durum wheat, Provide did not increase yield as
compared to the untreated control at nine site-years in Manitoba and Alberta
60
Control
Provide alone
Provide + 10 lb P
20 lb P
40 lb P
50
Grain Yield
-1
(bu acre )
• Adding Provide alone was
equal to the untreated
control
• Adding Provide plus 10 lb
of phosphate gave yield
response of about ½ of
applying 20 lb of
phosphate
• Significant yield increase
with P but no significant
benefit of provide
40
30
20
Mean
Minnedosa
Grant et al. (2002)
Flax Yield Did Not Respond to Either Side-banded P
or Provide in Nine Site-Years in Manitoba
35
Grain Yield
(bu acre-1)
30
Control
20 P
Provide
25
20
15
10
5
0
Brandon
Minnedosa
Rosebank
Effect of P. bilaii and P fertilizer on wheat and barley
barley grain yield
– 20 site years
60
160
55
140
Barley Yield (Bu/acre)
Wheat Yield (Bu/acre)
47 site years
50
45
P alone
P + P.bilaii
40
35
120
100
P alone
P + P.bilaii
80
60
0
9
18
P Rate (kg/ha)
27
0
9
18
P Rate (kg/ha)
Karamanos
27
Mycorrhizal Association May Improve P Availability
• Mycorrhizae are an association
between plant roots and a fungus
– Especially important for flax and corn
– Do not occur with canola or sugar beet
– Mycelium grows into the soil and increases
area mined for nutrients
• Fungi gives nutrients to plant and
plant gives sugars to the fungi
• Mycorrhizae are reduced by:
–
–
–
–
Tillage
Summer fallow
P fertilization
Following a nonmycorrhizal crop
Plant Root
Benefit of Inoculation with Mycorrhizae Uncertain
• Inoculation with mycorrhizae not widely
tested in field conditions
• Native mycorrhizae exist naturally in soils
– Inoculation may not be needed under many
conditions
• Some crops are more dependant on
mycorrhizae
– Flax or corn versus wheat
• Crop “pays” mycorrhizae with photosynthate
– If cost is greater than benefit, AM may decrease
yield
In nine site-years in Manitoba and Alberta colonization in
wheat roots was increased by inoculation and reduced by P
-Colonization%
30
*
25
*
20
15
*
10
P Fertilizer
Control
Myc
5
0
Lacombe
MCDC
Maziers
Biomass at Six Weeks Tended to Decrease
with Mycorrhizal Inoculant
Biomass Yield
(T ha-2)
1.6
**
1.2
Control
P Alone
Mycorrhiza
Mycorrhiza + P
0.8
0.4
0.0
Lacombe
MCDC
Maziers
Biomass yield at heading also tended to decrease
with inoculation
*
Mycorrhizal Inoculation Did Not Affect Wheat Grain
Yield in Nine Site Years in Manitoba and Alberta
Inoculant tended to reduce grain yield at Philips in 2005
25
No Myc.
Myc
• Yield was higher with P
fertilizer than inoculant
alone
• Grain yield was reduced
at Philips when
inoculant was added
with fertilizer
Grain Yield
(bu acre-1)
20
15
10
ol
C
tr
n
o
M
AP
SB
P
R
C
SB
P
P
A
SB
P
AP
.
ib
r
D
Effect of mycorrhizal inoculation
• Mycorrhizal inoculation increased
colonization
– Tended to decrease early biomass
production
– No benefit on final grain yield
– Sometimes led to a small decrease in yield
• Mycorrhizae may “cost” wheat more
than they contribute
• Need more information on other crops
– Effect may differ with flax
Summary
• P use efficiency in the year of application can be low
– 25 to 30%
• P reacts in the soil to forms that are less available than
original fertilizer
– However plants can still access this P in following years
48
Summary
• Banding starter P placed close to the seed is important
to optimize crop yield
• Cutting rate too low may not place P close to each seed
• Little difference between MAP and other new
formulations under Manitoba conditions
–
–
–
–
Fluids vs dry
Orthophosphates vs polyphosphates
Avail treatments
Polymer coating
49
Summary
• Provide does not appear to be highly beneficial under
field conditions
• Inoculation with mycorrhizal spores can increase
colonization in wheat
– Does not lead to yield increase
– May decrease yield under some conditions
• Inoculation needs more testing with mycorrhizaldependent crops like flax
50
Summary
• Crop removal of P is fairly well balanced with P addition
in non-manured fields
• P use efficiency may be higher than we think
• Cutting application rates to less than crop removal may
not be desirable
– Too little P for plant roots to physically access
– Long-term depletion of soil P
– Crop productivity is lower on P depleted soils
• Band an available form of P near the seed row at rates
that reflect crop removal over the cropping sequence
51
Thank You
For your
Attention