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Proceedings of the 2015 Nitrogen:
Minnesota’s Grand Challenge & Compelling
Opportunity Conference
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written consent of author(s)
Opportunities and Challenges
When Applying Nitrogen In-Season
Fabián G. Fernández
Nutrient Management & Water Quality Specialist
Department of Soil, Water, and Climate
[email protected]
Nitrogen: Minnesota’s Grand Challenge & Compelling Opportunity Conference
6 Mar. 2015, St Cloud, MN
• Nitrogen management is risk
management
– So many unpredictable variables among
some constants can make it a “game of
chance”
• Need to manage based on probability
EONR
99 (108) 122
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The Nitrogen Cycle
X
X
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R1, 70%
V6, 10%
Bender et al.
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Pros and Cons
• Fall N
– Spread work load
– Soils possibly better fit for application
– Anhydrous may be cheaper
• Nitrification inhibitor should be used
• Efficiency of N may be reduced
– Potential for loss is greater
– Not a BMP and limited use based on
location and soils
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Anhydrous Ammonia Timing
(2-yr study)
26 lb N/acre more
7 bu/acre less yield
$0.40/lb N*26=$10.40
$4/bu*7=
$28.00
Total=
$38.40
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Pros and Cons
• Pre-plant
– You are “done”
– It can delay planting
– Less concern if it gets dry
• Can increase N availability if it gets dry later for
sidedress (getting N in the root zone)
• Lower concern for N loss relative to sidedress in a dry
year
– More concern if it gets too wet
• Can increase N loss in wet years
– Less concern about crop injury
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• Sidedress
Pros and Cons
• Can manage N based on crop needs and past weather
• Can help reduce further planting delays
• Getting in the field in time
– High clearance equipment
– Loss of yield potential
• Role of starter more important?
• Split applications
•
•
•
•
Spread the risk
More trips/time
May not be necessary
No brainer for irrigated fields (fertigation or water to
incorporate)
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Wet Spring Early Pre-Plant vs. at Planting
Corn-corn
PP1: Pre-plant >4
weeks before planting
PP3: Pre-plant within
a week before
planting
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Dry Spring With Low N Loss
Potential
a
a
a
a
ab
a
b
Fall anhydrous ammonia (AA) had N-Serve
Sp= spring pre-plant within a weeks before planting
Planted May 19, 2011
SD= sidedress application end of June
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b
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Yield at 160 lb N/acre
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What N Source and How Should You
Apply Sidedress N?
• What make most sense for speed, protect the
crop from injury, and reducing N loss?
– 1) Injected anhydrous ammonia or UAN solution
between rows
– 2) Broadcast ammonium-containing fertilizers
(ammonium sulfate or ammonium nitrate)
– 3) Broadcast urea with Agrotain
– 4) Dribble UAN solution between rows
– 5) Broadcast UAN solution
• 90 lb/a @ V4-5; 60 lb/a @ V8; with herbicide reduce rate
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2014 New Richland, Waseca Co.
PP: EONR 157 lb N/a, 162 bu/a
Canisteo-Glencoe and Webster clay
loam, 0 toNutrient
2 percent Management
slopes
2014 St Charles, Winona Co.
PP: EONR 171 lb N/a, 181 bu/a
Seaton silt loam soil 3-6% slope
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Marna silty
clay loamManagement
and Nicollet silty clay loam
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End of Season Nitrate, Corn Plots
MRTN 138 lb N/a
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Quest to Finding the Best
Time for Sidedress, 2014
Location Planting
Rotation date
Becker
5/14
C-C
Clara City
5/30
C-C
SWROC
5/30
C-C
SROC
5/23
C-C
SROC
5/11
C-S
Theilman
5/22
C-C
Lowest Highest
yield
yield
Response equation
R2
30
103
y = 0.2192x + 36.89
0.91
53
137
0.83
86
149
y = 0.3202x + 55.229
y = -0.0014x2 + 0.5448x +
92.832
47
140
0.92
71
150
y = 0.3781x + 51.183
y = -0.002x2 + 0.7963x +
70.319
109
206
y = -0.0033x2 + 1.1x + 102.85
0.82
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0.92
0.99
Lamberton, Yield
b
b
ab
ab
a
PP: EONR 124 lb N/a, 142 bu/a
c
Ves loam soil
ab
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Soil N with Pre-plant Applications
Soil with 4% OM, CEC 24 meq/100g
Ves loam soil
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Lamberton, C-C at 120 lb N/a
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Becker, 2014
Hubbard loamy sand
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Soil N with Pre-plant Applications
Soil with 1.6% OM, CEC 8 meq/100g
Hubbard loamy sand
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Becker, 2014 C-C at 120 lb N/a
Hubbard loamy sand
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Pope Co, MN, C-C, 2013
Arvilla sandy loam
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Urea PP+V4
Others PP
Pope Co, MN, C-C, 2014
Arvilla sandy loam
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Urea PP+V4
Others PP
Pope Co. MN, C-S, 2013
Arvilla sandy loam
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Urea PP+V4
Others PP
Pope Co. MN, C-S, 2014
Arvilla sandy loam
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Urea PP+V4
Others PP
Dakota Co. MN, C-C, 2013
Sparta loamy fine sand
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Urea PP+V4
Others PP
Dakota Co. MN, C-C, 2014
Waukegan silt loam, 1 to 6%
slopes Nutrient Management
Urea PP+V4
Others PP
Irrigated Sandy Soil Corn
Dakota Co. corn/corn
2011
2012
2013
2014
Trt
Pope Co. corn/corn
2011
2012
2013
2014
Pope Co. Corn/soybean
2011
2012
2013
2014
Corn grain yield (bu/A)
Check
150
100
87
69
82
83
79
83
111
174
126
118
Urea
BMP
238
208
216
200
180
223
186
149
194
197
187
206
Super U
223
175
223
176
172
235
162
127
187
159
202
181
ESN
222
198
214
177
172
234
178
129
179
187
202
179
ESN/Urea 220
188
211
195
172
211
164
138
169
168
200
184
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Can We Use Crop Sensors To
Improve N Management?
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Lamberton, C-C
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Using Canopy Sensors
• The earlier the sensing the greater the
flexibility to apply nitrogen, BUT
• The earlier the sensing the lesser the
predictive power
• The later the sensing the greater the
predictive power, BUT
• The later the sensing the lesser the flexibility
to apply nitrogen and greater potential for
yield loss
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How Much N is Naturally in the
Soil and Available to Crops?
• About 5% of OM is N
• Each 1% OM in top 7 inches = 20,000 lb OM/acre
• Annually, about 1 to 3% of the organic N converts into
plant-available N
• Soil with 3.5% OM = 3,500 lb organic N
– 35 to 105 lb of N per acre per year
• Deeper soils can provide more
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• 3.5% OM = 3,500 lb N/a x 3% release ≈
105 lb N/A
• 100 lb N/a in residue x 50% plt. avail. ≈
50 lb N/A
• N deposited by precipitation ≈
10 lb N/A
• Non Fertilizer N supply ≈
165 lb N/A
• 200 bu/a crop ≈
240 lb N/A
• N needed from fertilizer ≈
75 lb N/A
– 55-65% taken up by crop
– 20-25% goes to OM
– 15-20% denitrified, leached, volatilized, weed uptake
• If efficiency is 60% ≈ 125 lb N/A to supply 75 lb N/A
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How Much Yield Can We Get Through
Mineralization in MN?
Percent of Corn Yield at EONR Obtained from the
0-N Check 53% C-C, 71% C-S
52 bu/a
58 lb N/a
218 bu/a
244 lb N/a
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Ave:116 bu/a
130 lb N/a
If All Else Fails, Then
What?
Rescue Treatments Should
be Just That
(Don’t make rescue applications
part of your management plan)
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Where and When Should You
Apply Supplemental N?
• If N deficiency is present or you know the
crop will run out of N
• Priority should be corn-corn fields or
where potential for N response is highest
• Preferably by the time the corn is shoulder
high (to improve yield and ease of
application)
• Little past tassel if deficiency is severe?
• Thou shalt use thy head!
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What N Source and How Should
You Apply Supplemental N?
• Fly urea
• Urea with a high-clearance
spinner or dry boom
• UAN solution with drops or
injection arms
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Take Home Message
• Split N or sidedress in dry-land may produce
similar yields to spring pre-plant
– There may be non-agronomic benefits
– Just like with pre-plant, split N carries risks
– Do not use slow-release products in-season
• Split N applications work well for irrigated sands
• Canopy sensing predicts yield better later in the
season
– Soils can provide substantial amounts of N
– Early in the season the crop normally has more than
enough from the soil
• Rescue treatments should be used only as needed
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Thank You!
• U of M Nutrient Management Group
• Graduate & Undergraduate Students, post Docs
• Research Center Personnel and Farmers
• Funding entities:
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Questions
Fabián Fernández
[email protected]
Nutrient Management