Corn Fertilization Systems

Corn Fertilization Systems
A corn crop requires several nutrients, including nitrogen (N), phosphorus (P), and potassium (K). Some of the aspects that
can affect plant availability of applied nutrients include tillage system and timing of application. Adjustments to nutrient
application timing and tillage practices are tools being evaluated to help increase yield potential and economic return.
Study Guidelines
Testing was conducted at the Monsanto Water Utilization
Learning Center at Gothenburg, Nebraska to evaluate
different methods of managing nutrient application in corn.
Plots were planted on May 3rd, at 34,000 seeds/acre. There
were five treatments that included different variations of tillage
practices and fertilizer application timing (Table 1).
Fertilizer rates were constant across treatments, with a total
of 200 pounds/acre of N and 60 pounds/acre of P applied preplant (PRE), as pop-up at planting, or side-dress. Fertilizers
used in the demonstration included dry urea, mono-
ammonium phosphate (MAP), 28% urea ammonium-nitrate
(UAN), and 10-34-0. All treatments received 5 gallons/acre of
10-34-0 as pop-up fertilizer at planting. Side-dress
applications were applied to corn at V4 to V5. Leaf tissue
samples were collected at V10. For a relative check of N
deficiency, half of each treatment received 60 pounds/acre of
N applied to the soil surface, by hand, near VT.
Results and Discussions
N Deficiency. Leaf tissue samples indicated N deficiency in all
treatments that did not receive a side-dress application of N.
to pg. 2
Table 1. Treatments for evaluating corn fertilization systems. Net profit based on $5/bushel corn and $0.50/pound of N.
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Trmt.
Tillage
Pre-plant
Pop-up at
Planting
1a
No-Till
Urea and MAP (194#N, 40#P)
6#N, 20#P
1b
No-Till
Urea and MAP (194#N, 40#P)
6#N, 20#P
2a
Conv.
Urea and MAP (194#N, 40#P)
6#N, 20#P
2b
Conv.
Urea and MAP (194#N, 40#P)
6#N, 20#P
Side-dress
60#N
60#N
28% UAN
(100#N)
28% UAN
(100#N)
3a
Conv.
Urea and MAP (94#N, 40#P)
6#N, 20#P
3b
Conv.
Urea and MAP (94#N, 40#P)
6#N, 20#P
4a
Strip-Till
10-34-0 and 28% UAN
with strip-till (144#N, 40#P)
6#N, 20#P
28% UAN
(50#N)
4b
Strip-Till
10-34-0 and 28% UAN
with strip-till (144#N, 40#P)
6#N, 20#P
28% UAN
(50#N)
5a
Strip-Till
5b
Strip-Till
10 gallons/acre of 10-34-0 + 15 gallons/
acre of 28% with strip-till (94#N, 40#P)
10 gallons/acre of 10-34-0 + 15 gallons/
acre of 28% with strip-till (94#N, 40#P)
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6#N, 20#P
6#N, 20#P
Near
VT
28% UAN
(100#N)
28% UAN
(100#N)
60#N
60#N
60#N
Yield
(bu./acre)
Net Profit
per acre
254
#1,261.46
255
$1,240.34
219
$1,077.52
247
$1,197.35
254
$1,262.61
262
$1,274.57
225
$1,106.68
256
$1,247.39
242
$1,199.92
262
$1,277.75
Corn Fertilization Systems
from previous page
Plants from the two treatments that included side-dress
applications of 100 pounds/acre of N were low in N, but not at
deficient levels.
N PRE only
Differences in foliar symptoms of N deficiency were seen
across treatments (Figure 1). Treatments that received a sidedress application of N showed less N deficiency, especially in
the conventional tillage system.
to pg. 3
N PRE followed by Side-dress
No-till
60 pounds/acre of N near VT
Conv.
Tillage
60 pounds/acre of N near VT
60 pounds/acre of N near VT
60 pounds/acre of N near VT
60 pounds/acre of N near VT
Striptill
Figure 1. Visual differences in N deficiency symptoms from different
application timings of N in different tillage systems. Note less N deficiency
visible in treatments with split applications of N.
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Corn Fertilization Systems
Yield (bushels/acre)
from previous page
270
260
250
240
230
220
210
200
190
PRE
No-Till
N Near VT
No Second Application
Figure 2. Better ear fill was seen when 60 pounds per acre of
N was applied prior to tassel. These examples are from no-till
treatment.
Ear Fill. Additional N near VT helped with ear fill. Figure 2 is
an example of less kernel abortion with more N near VT.
Yield (without N near VT): Tillage. In treatments without an N
application near VT which received the majority of N through
PRE applications, the no-till system yielded 35 and 29 bushels/
acre more than the conventional and strip-till systems
respectively (Figure 3). Split Applications. In treatments without
an N application near VT, split applications of N in conventional
and strip-till systems respectively, resulted in 35 and 17 bushels/
acre and $185.09 and $93.24 net profit/acre, using $5 corn and
$0.50/pound N for the calculations (Figure 3).

Yield (bushels/acre)
220
210

PRE
Strip-Till
Split Application
Figure 3. Effect of tillage and split application on corn yield,
without an N application near VT.
Strip-Till
60 pounds/acre of N at VT
Conclusions

Conv. Till
Split
Application
Yield. N Near VT: There was a positive yield response to the
application of 60 pounds of N in each of the five treatments,
which averaged 17.6 bushels/acre (Figure 4). In the
conventional and strip-till systems, the N application near VT
produced 29.5 and 14 bushels/acre and $130.27 and $44.90
net profit/acre more following the PRE and split N applications
respectively. Net profit calculations are based on $5/bushel
corn and $0.50/pound N.
240
No-Till
Conv. Till
PRE
Figure 4. Effect of N application near VT across tillage systems
and application timings (PRE vs. Split).
250
200
Split
Application
0 pounds/acre of N at VT
260
230
PRE

Split applications of N resulted in higher yields and more
net profit in both conventional and strip-till systems.
Evidence from this demonstration indicates hybrids can
have a positive yield response to a late season N
application made near VT, even when only minor visual
deficiency symptoms are apparent.
The additional 60 pounds/acre of N resulted in more yield
in all five treatments. The additional yield is possibly a
result of less kernel abortion at the ear tip, and/or more
favorable timing of silk emergence and pollen availability.
Fertilizing for a 300 bushel corn crop is likely to take
different management techniques than fertilizing for a
200 bushel corn crop.
In 2011, there are plans to evaluate more hybrid and trait
combinations.
The information discussed in this report is from a single site, non-replicated, one-year demonstration. This informational piece is designed to report the results of
this demonstration and is not intended to infer any confirmed trends. Please use this information accordingly.
Individual results may vary, and performance may vary from location to location and from year to year. This result may not be an indicator of results you may obtain as local
growing, soil and weather conditions may vary. Growers should evaluate data from multiple locations and years whenever possible. Technology Development by Monsanto and
Design® is a registered trademark of Monsanto Technology LLC. All other trademarks are the property of their respective owners. ©2011 Monsanto Company. 01.26.2010.EJP
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