How Does Canola Get Its Nutrients?cerebralfocus.com/brandoncanola/webcast/how_canola.pdf · How...
Transcript of How Does Canola Get Its Nutrients?cerebralfocus.com/brandoncanola/webcast/how_canola.pdf · How...
How Does Canola Get Its Nutrients?
C.A GrantAgriculture and Agri-Food Canada
Brandon Research [email protected]
N CaP Mg
K S
17EssentialElements
17EssentialElements
Canola Needs a Total of 17 Elements
C H O
B Cl Cu FeMn Mo Zn Ni
N CaP Mg
K S
17EssentialElements
17EssentialElements
Some come from the air or water
C H O
B Cl Cu FeMn Mo Zn Ni
N CaP Mg
K S
17EssentialElements
17EssentialElements
Others are usually present in adequate amounts in prairie soils
C H O
B Cl Cu FeMn Mo Zn Ni
N CaP Mg
K S
17EssentialElements
17EssentialElements
N, P and S are most often limiting for canola production
C H O
B Cl Cu FeMn Mo Zn Ni
Nitrogen is Critical for Crop Growth
• Usually most limiting nutrient
• Largest fertilizer input• Required for optimum
yield and protein
How Much Nitrogen is Removed by a Canola Crop?
• A 40 bu/acre canola removes about 85 lb N per acre
• About 40 lb more taken up but recycled in residue
• About 125+ needed for growth
Daily Uptake of N By Canola Reaches 6 to 8 lb per acre per day About 6-8 Weeks after Seeding (6 leaf stage)
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3 4 5 6 7 8 9 10 11 12 13 14 15Weeks after Seeding
N u
ptak
e ra
te, l
b N
/acr
e/da
y
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Biom
ass accumulation rate,
lb/acre/day
6 le
af s
tage
Carstairs
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3 4 5 6 7 8 9 10 11 12 13 14 15
Weeks after Seeding
N u
ptak
e ra
te, l
b N
/acr
e/da
y
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Biom
ass accumulation rate, lb/acre/day
Bud
ding
sta
ge
6 le
af s
tage
Olds
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Nitr
ogen
upt
ake
rate
, lb/
acre
/day
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iomass accum
ulation rate, lb/acre/day
6 le
af s
tage
Rosser
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Weeks after Seeding
Nitr
ogen
upt
ake
rate
, lb
N/a
cre/
day
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Biom
ass accumulation, lb/acre/day
6 le
af s
tage
Petersfield
(Courtesy Rigas Karamanos)
Mineralization
Immobilization
Plants Access N from Soil
Nitrate and ammonium in solution and on exchange
Fertilizer additions make up the difference between crop demand and soil supply
Nitrogen Reactions Influence Availability from Soil and Fertilizer
AmmoniumNH4
+
46-0-082-0-0
28-0-0 (75%)
Manure &Crop Residues
NitrateNO3
-Soil Organic N
Leaching & runoff
N2, N2O Denit’n
NH3Volat’n
Immobilization
AmmoniumNH4
+
46-0-082-0-0
28-0-0 (75%)
Manure &Crop Residues
NitrateNO3
-Soil Organic N
Leaching & runoff
N2, N2O Denit’n
NH3Volat’n
Immobilization
AmmoniumNH4
+
46-0-082-0-0
28-0-0 (75%)
Manure &Crop Residues
NitrateNO3
-Soil Organic N
Leaching & runoff
N2, N2O Denit’n
NH3Volat’n
Immobilization
NO
Crop Removal
Mineralization
Reactions and Losses Depend on Environment and Management
• Nitrogen losses can be high, with poor management or under bad conditions
• Management practices can be used to minimize losses
Volatilization can be high with broadcast urea if not incorporated
Fertilizer N
NitrateNO3
-
AmmoniumNH4
+
Leaching, runoff
Denitrification
N2NO N2O
Nitrification
NH3
volatilization
40-90% of urea-N under hot, dry conditions
Banding Reduces Ammonia Losses to Extremely Low Levels
0
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500
Am
mon
ia (g
N h
a -1
)
Fall Spring pre-seeding
After Seeding
CT-ControlCT-UncoatedRT-ControlRT-Uncoated
• If urea bands were sealed, losses were no higher than from the control – grams per hectare
• Some losses occurred under RT when band did not seal
Brandon ZTF
Leaching can be high on sandy soils with excess rain or irrigation
Denitrification can be high on warm, saturated soils
Fertilizer N
NitrateNO3
-
AmmoniumNH4
+
Leaching, runoff
Denitrification
N2
NO N2O
Nitrification
2-4 lb N/ac/day under saturated soil conditions
Banding an Ammonium-Producing Source Reduces Leaching and Denitrification Losses
• Ammonium must convert to nitrate before it is susceptible to loss– Slows conversion of ammonium to nitrate– Lowers nitrate concentration in the solution– Reduces the risk of loss
r = 0.66*
r = 0.11ns
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120
10-Sep 20-Sep 30-Sep 10-Oct 20-Oct 30-OctDate of application
Gra
in y
ield
(% o
f spr
ing)
Highs Lows Linear (Lows) Linear (Highs)
Thiessen et al. – U. of Manitoba
Supported by data from U. of Manitoba that showed losses from fall-banded N fertilizer were minor on well-drained soils
Soil freezesCrop
harvest
Upper slope
Lower slope
Much of our N “Loss” may be Cycling via Immobilization-Mineralizationimmobilization - “tie up of N”mineralization - “release of N”
-15
-10
-5
0
5
10
133 159 181 202 222 251
Sampling date
N m
iner
aliz
ed (k
g/ha
)
Durum Stubble Pea Stubble
May
13
June
8
June
30
July
21
Aug
10
Sept
8
N tie-up N release
Selles
In-Soil Banding Reduces Immobilization
0102030405060708090
100
straw incorp N bcst
straw on surfaceN bcst
straw removed N bcst
straw incorp N band
straw on surfaceN band
straw removed N band
Rec
over
y of
fert
ilize
r N %
Immobilized NPlant N
Tomar and Soper, 1981
Fall recovery of fertilizer N in crop and soil
Immobilized Nitrogen is not a “Loss”
• Builds soil organic matter• Improve soil quality • Cycles back to following
crops– Improves soil’s ability to “buffer”
N supply in years when yield potential is high
• Need to consider both soil nitrate and mineralization to predict soil N supply
Mineral N
Soil Testing For Available N
• Provides indication of residual nutrient in soil– Nitrate “in the bank”
• Does not necessarily consider mineralization– “Interest on organic matter”
Older Systems May Rely More on Stored Soil Nitrate
• Soil nitrate released and stored over fallow period– “Mine” organic matter to
release N
• Intensive tillage increases mineralization and amount of nitrate in soil at seeding
• Continuous cropping and reduced tillage reduce the stored nitrate
• N fertilization and higher yield increase residue return to the soil
• May increase the importance of N mineralization from SOM and crop residues over the growing season
Can We Test for Mineralization?
• Specific tests predict “potential mineralization”– “Mason Jar test”– Long-term incubation – Have not been very useful so far in the prairie
environment for routine testing
• Tests measure release under ideal temperature and moisture
• Actual mineralization depends on environmental conditions
Potential Mineralization Increases with Soil Organic Matter Content
• More organic matter gives more potential for N release under the right conditions– Acts as “buffer” for N rate– Conditions that promote high
crop yield promote N release– As crop demand increases,
the ability of SOM to release N increases
y = 43.02x - 26.958R2 = 0.5375
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0 1 2 3 4 5 6
Soil Organic C (%)
Pot M
in N
(ppm
)
Past Management Can Affect N-Supplying Power of the Soil
Long-Term Building• Continuous Cropping • Diversified Crop Rotation
(cereal-oilseed- cereal-pulse)• Good N fertilization• Some forages before start of
zero tillage (1978-1983)• As of 2008, 30 years of no-till
Long-Term Depleting• 50/50 summerfallow/crop
rotation prior to 2001• Minimal N fertilizer• Conventional tillage• Crop Rotation (cereals
mainly)• No-till since 2001
Courtesy of Guy Lafond
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Nitrogen (kg/ha)
Yie
ld (b
us/a
cre)
BuildingDepleting
Spring Wheat (3 years) – Grain Yield
~30 kg/ha
How to Improve Nitrogen Use Efficiency?• Soil nitrate test is still a good indicator of
available N for crop growth in annual cropping systems
• Improve estimates of soil N supply to fine-tune application rates in modern systems
– Consider past inputs of legumes, manures and other soil building practices– Modelling or measurement of mineralization
• Match management practices to environment– Select proper rate, source, timing and placement of N fertilizers– Enhanced efficiency fertilizers and split applications may have role where
environmental conditions promote losses
• We may be underestimating nitrogen use efficiency if we don’t consider N balance over the long-term
Canola has a High Demand for P
Adequate P is needed for full response to N fertilizer
0.0
0.5
1.0
1.5
2.0
2.5
0 50 100 150 200 250
N (kg/ha)
Yiel
d (t/
ha)
0 20 40 60 80P2O5 kg /ha
Hybrid Canola
Westco
29
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– Need to apply 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
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How Much Phosphorus is Needed by a Crop?
• 40 bu/acre canola removes 38 lb/acre
• Additional 20 lb/acre is cycled in the residue
• Total of around 58 lb for growth
Without an adequate P supply, crop yield will be reduced
But not all crop requirement has to come from fertilizer
31precipitation
Plants Access P from Soil Solution
Soil solutionphosphorus
HPO4-2
H2PO4-2
Fertilizer additions make up the difference between crop demand and soil supply
dissolution
Mineralization
Immobilization
weatheringAdsorption
desorption
Factors that Restrict P Availability
• Low soil P reserves (soil test P)• Cold soil temperature• Excessively wet or dry soils• High or low pH (pH 6-7 ideal)• Fine soil texture (eg. clay)• Restricted rooting
– Compacted, poorly aerated soils – Crops with poor root systems for P uptake
Need for P fertilizer will be higher if P availability is restricted
Phosphorus is Relatively Immobile in the Soil
Has important effect on P management decisions
34
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
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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
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Some crops can increase rooting when they contact a fertilizer reaction zone
02468
10
Roo
ts in
R
eact
ion
Zon
e (%
)
FlaxWheat
Rapeseed
Buckwheat
Unfertilized SoilP Reaction Zone
• Canola is very good at increasing rooting in the fertilizer band– Very good at using
fertilizer P
• Also very good at using residual soil P– Excretes organic acids
to mobilize PStrong and Soper
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Banding P Near the Seed-Row Ensures that Roots Will Contact the P Granule Early in Growth
BroadcastBroadcast BandedBanded
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
38
Phosphorus Should be Banded
• P will not move to roots so roots must contact bands
• Bands must be placed where roots will contact them early in season– Near the seed-row
• Seed-placed• Side-banded
Effect of rate and placement of MAP on stand density and grain yield of canola
• Too much fertilizer close to the seed can damage the seed and reduce yield
• Damage is from the nitrogen in the MAP
0.0
0.5
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1.5
2.0
0 20 40 80P2O5 Rate (kg/ha)
Gra
in Y
ield
(kg/
ha)
0
50
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250
plan
ts p
er 6
.1 m
Yield-In RowStand-In Row
Nyborg and Hennig 1969.
40
Canola
• Canola is highly responsive to P on very low P soils– Can use soil P well if soil test P
is moderate to high• Yield will usually be optimized with
15 to 20 lb P2O5 ac-1
• Place as starter near or in the seed-row
• Response to starter more likely on cold soils, with early seeding
No Starter P
35 bu/acre25 bu/acre
25 lb P2O5 applied as MAP
15 lb NW MKP per ac, equiv. to ~ 7 ppm Olsen P
Sulphur Deficiency is Very Common In Canola
• Canola requires more S than cereal and pulse crops.
348124Sulphur removal (kg/ha)
AlfalfaPeasCanolaWheat
42precipitation
Plants Access S from Soil Solution
Soil solutionSO4
-2
As with other nutrients, fertilizer additions make up the difference between crop demand and soil supply
dissolution
Mineralization
Immobilization
Rain,irrigation, atmospheric deposition
Gypsum
Sulphur Deficiency
Sulphur is not mobile, so does not move from old to young tissue
Yellowing of younger leaves is early symptom
Often the S deficiency results in a reddish-violet color, similar to P and N.
Cupping of younger leaves is a symptom of critical S stress,
Sulphur Deficiency Symptoms
• Sulphur deficiencies are usually patchy in a field, since S supply is normally highly variable
Adding N without S Can Depress Canola Yield on an S-deficient soil
0.0
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1.2
Can
ola
Yiel
d (t/
ha)
ControlN bandedN broadcast
Grant 1994
Increasing N with S
Increasing N with No S
Adequate S is Needed, But Specific N:S Ratio May Not Be That Important
• High N:S ratio can indicate an S deficiency
• However, once a S deficiency is corrected there is little or no response to adding more S with increasing N rate.
Sulphur Sources
• Ammonium sulphate• Ammonium
thiosulphate• Gypsum • Microessentials S-15
• Elemental S• Bentonite blends
– Tiger 90
• Microessentials S-15
Sulphate Sources Elemental Sources
Manage sulphate and elemental sources differently
Sulphate Sources Are Immediately Available so Timing of Application is Flexible
• Ahead of seeding– Will not volatilize– May immobilize or leach
• Near seeding– Readily available
• Post-seeding– Can be effective, even when delayed
Sulphate Sources Are Mobile in the Soil so Placement Options Are Flexible
• Banding• Broadcast• Dribble-band• Seed-placement
– Avoid excesses that could cause toxicity
Elemental Sources Must Oxidize to Sulphate
• Apply far before crop requirement• Use finely divided product• Broadcast rather than band
– Want to maximize contact with microbes
• Leave on surface to “weather”• Incorporate after weathering• Part of long-term program
Canola yield as affected by placement of applied sulphur
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2500
Seed
Yie
ld (
kg/h
a)
Broadcast Seedplaced PP Band
Control Tiger 90 Am. Sulph.
Canola yield as affected by residual S applied the previous year
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2000
Seed
Yie
ld (
kg/h
a)
Broadcast PP Band
Control Tiger 90 Am. Sulph.
Effect of a single year’s application of S sources on canola yield over three years on a sandy loam soil
Treatment Year 1 Year 2 Year 3 TotalControl 18.1 9.3 11.0 38.4Sp. Brd T-90 15.3 14.7 25.0 55.0Sp. Brd AS 34.6 31.4 24.0 90.0Banded T-90 16.0 10.4 12.3 48.7Banded AS 35.7 31.5 28.1 95.3Seedrow T-90 16.6 13.7 18.6 48.9
Conversion of S to Sulphate is not Reliable
• Under Canadian conditions, we cannot rely on elemental sources to provide enough available sulphate on deficient soils during the following crop year– May be beneficial in long-term planning
Summary
• Canola is effective at accessing nutrients from the soil– Also good at using fertilizer nutrients
• Need to consider soil nutrient supply when assessing fertilizer demand– Immediately available nutrients and potential
mineralization• Select proper rate, source, timing and placement
– Match management practices to environment to minimize losses and maximize efficiency
Thank YouFor your Attention