Corn Water Use Considerations
TAWC Water College 2016
Cody Daft – DuPont Pioneer
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The importance of irrigation to U.S.
corn production is demonstrated by
the fact that irrigated corn accounts
for nearly 20% of the corn crop while
occupying only 15% of acres
Most irrigated corn is grown in the
semi-arid Great Plains region of U.S
Where concern exists regarding declining surface
and groundwater supplies
Improving management practices is critical for
sustaining water resources
This presentation highlights irrigation
practices and other agronomic
management strategies to help
maximize grain produced for each
increment of limited irrigation water
applied
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1/25/2016
Where should our heads be?

Top things to keep in mind when we don’t have 100% of the
water we need….
1.
2.
How does our crop respond to water?
–
How can a change in irrigation practice affect water
needs?
–
3.
Growth stage, timing, population, fertility
Spray, bubble, slow, fast, early, late, ET
How can a change in agronomic practice affect water
needs?
–
Mapping soil types, crop residue, tillage, planting population, crop
rotation
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Crop Residue Benefits
Changes in agronomic
practices such as no
till can increase the
capture and utilization
of precipitation and
reduce irrigation water
needs
UNL Research has
shown that standing
residue can account
nearly 2” in
increased soil water
over flat residue
In one year, standing
residue accounted
for nearly 4” more of
stored soil moisture
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Evaluating Pre-Plant Irrigation
WUE of pre-plant irrigation is often very low, especially
when using spray mode in contrast to LEPA
•Efficiency may be as little as 20%, especially for early spring
applications – Wind, High Temps, No cover
•Wetting the entire surface of the soil greatly diminishes efficiency
•Can be improved by irrigating into standing residue from high
residue crops (Corn, Wheat, Sorghum)
VS
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Seasonal Crop Water Use in Corn
•Range 15 to 32 inches per year
•Median 25 inches per year
•50% used during reproductive stages
•Peak use about 0.35 in/day
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Corn growth and development review
c
d
b
a
a. Emergence; b. Initiation of ear size; c. Tasseling; d. Grain fill
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Abnormal ear growth helps
determine when the corn plant was
stressed
Ear growth occurs at clearly defined stages of plant growth
If an abnormality occurs in the ear, this defect is not corrected
as the plant matures
The corn ear serves as a “diary” that records stressful events
during the growing season
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Number of kernel rows around
determines corn stress level before V6
Primary ear (V14 node) corn
stage V9
Photo courtesy of Dr. Antonio Perdomo
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Most hybrids
produce 16 kernel
rows around the ear
If > 16, lush
growing conditions
(Population too
low?)
If < 16, stress
(Chronic drought
stress?)
Reference: Strachan, S. D. Corn
grain yield in relation to stress
during ear formation. Pioneer Crop
Insights Vol. 14 No. 1.
Kernel rows double at about V7 to V10
Primary ear (V14 node) corn
stage V9
Primary ear: corn stage V12
Final
doubling of
kernel rows
has started Photo courtesy of Dr. Antonio
Photo courtesy of Dr. Antonio
Perdomo
Perdomo
Reference: Strachan, S. D. Corn grain yield in relation to stress during ear formation.
Pioneer Crop Insights
Vol. 14 No. 1.
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Crop Water Use and Growth Stage
Crop Water Use (in/day)
0.6
Critical window
0.5
12 leaf Silking
0.4
Blister Kernel
Beginning Dent
0.3
0.2
Maturity
0.1
0
10-Apr
10-May
9-Jun
9-Jul
8-Aug
Date
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7-Sep
7-Oct
Crop Evapotranspiration (ET)
Driven by tremendous drying
force the atmosphere exerts on
soil/plant surfaces
High solar radiation and air
temperatures, low humidity,
clear skies and high wind
increase ET
Cloudy, cool and calm days
reduce ET
Seasonal ET is also affected by
growth stage, growing season length,
soil fertility, water availability and
interaction of these factors
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Hale County, TX Annual Precipitation
~12” during the growing season
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
0.63”
0.62”
0.87” 1.42” 2.92” 2.90” 2.39” 2.07” 2.12” 1.68” 0.68” 0.76”
19.29”
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Sep
Oct
Nov
Dec
How Effective is our Annual Precipitation
Hale County, TX
3000
2500
1908-2012 6073 Rain Events
2471
40%
2000
1500
1328
22%
1000
991
16%
13%
500
0
790
<0.1"
0.1-0.25" 0.25"-0.50"
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0.5"-1"
414
7%
79
1"-2"
>2"
Planting Date Effects on Crop
Water Use
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April 15th Corn 100% ET
0.55
0.5
Total ET 34.54”
0.45
0.4
0.35
0.3
0.25
0.2
0.15
0.1
0.05
0
0
20
40
60
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80
100
120
140
May 15th Planted Corn
0.45
Total ET 31.36”
0.4
0.35
0.3
0.25
0.2
0.15
0.1
0.05
0
0
20
40
60
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80
100
120
140
June 10th Planted Corn
0.4
Total ET 27.39”
0.35
0.3
0.25
0.2
0.15
0.1
0.05
0
0
20
40
60
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80
100
120
140
Split Planting Scenarios to Spread Water
More Flexibility, Less Risk if Main Crop is Planted First
If you plant your “companion” crop early, you could regret watering it
too much if the year turns out dry
If companion crop is planted later, you are in the driver’s seat on
your decision making – you can keep the water on the primary crop
100% if needed
• Decrease companion sorghum seeding rate to insure success if minimally
watered
• Decrease companion cotton seeding rate and switch to more
indeterminate variety
• Decrease companion corn seeding rate and switch to earlier maturity
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IRRIGATION WATER SUPPLY
27,300 gallons/acre inch
Gallons/Min/
Acre
1.0
Acre
Inches/Day
Acre
Inches/Week
0.053
0.37
2.0
0.107
0.75
3.0
0.160
1.12
4.0
0.214
1.50
5.0
0.267
1.87
6.0
0.320
2.24
7.0
0.373
2.61
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April 15th Corn, May 25th Cotton
0.5
0.4
0.3
.28 = 75% ET
0.2
.15 = 60%ET
0.1
0
0
25
50
75
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100
125
150
175
May 5th Cotton, June 10th Corn
0.4
0.35
0.3
0.25
.26 = 75%ET
0.2
.21 = 60%ET
0.15
0.1
0.05
0
0
50
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100
150
April 15th Corn, June 15th Sorghum
0.5
0.4
0.3
.28 = 75% ET
0.2
.17 = 60%
0.1
0
0
25
50
75
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100
125
150
175
April 15th Corn, June 10th Corn
0.5
0.4
0.3
.28 = 75% ET
.26 = 75%ET
0.2
0.1
0
0
50
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100
150
200
In Depth Understanding of Soil
Type and Characteristics is
critical to success
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Soil Water Characteristics by Soil Type
Inches of Water/Foot of Soil
Sand
Loam
Clay Loam
Saturation
5.2
5.8
6.1
Field Capacity
2.1
3.8
4.4
Permanent Wilting
Point
1.1
1.8
2.6
Gravitational
3.1
2
1.7
Water Holding
Capacity
1
2
1.8
Plant Available
0.5
1
0.9
Unavailable
1.1
1.8
2.6
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Soil Type Characteristics with relation to Plant
Available Water
Water Holding
Capacity
Inches/Foot of Soil
Plant Available
Inches/Foot of Soil
Coarse Sand
0.25 – 0.75
0.13 – 0.38
Fine Sand
0.75 – 1.00
0.38 – 0.5
Loamy Sand
1.10 – 1.20
0.55 – 0.60
Sandy Loam
1.25 – 1.40
0.63 – 0.70
Fine Sandy
Loam
1.50 – 2.00
0.75 – 1.00
Silt Loam/Clay
Loam
2.00 – 2.50
1.00 – 1.25
Silty Clay Loam
1.80 – 2.00
0.90 – 1.00
Silty Clay
1.50 – 1.70
0.75 – 0.85
Clay
1.20 – 1.50
0.60 – 0.75
Textural Class
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Soil Water Extraction
40%
25
Percent of
50
Rooting Depth
75
30%
20%
100 10%
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Effective Root Zone
effective
root zone
2 ft
effective
root zone
reserve
Early in the growing season
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Later in the growing season
3 ft
Irrigation Scenarios,
Population Considerations,
and Hybrid Maturity based on
Water Availability
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Grain yield response to plant population across hybrids in four
irrigation treatments in Plainview, 2012-2014.
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32
Grain yield response to plant population across hybrids in four
irrigation treatments in Plainview, 2012-2014.
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33
Hybrid group grain yield response to plant population in 100 and 80
percent ET replacement, Plainview, 2012-2014.
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Hybrid group grain yield response to plant population in 55 and 40
percent ET replacement, Plainview, 2012-2014.
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Hybrid Groups – 55 and 60% ET Grain Fill Stress x Population
Hybrid group grain yield response to plant population in 55 percent
ET and 60 percent ET grain fill stress, Plainview, 2012-2014.
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Hybrid group grain yield response to plant population in 55 percent
ET early-late stress and 50 percent ET flower stress, Plainview, 20122014.
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Nitrogen Use Efficiency in Corn
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Nitrogen and Water Use Efficiency
Nitrogen Increases WUE In Wet or Dry Weather
N Rate (lbs/Ac)
Dry Year
Yield (Bu/Ac)
Wet Year
Yield (Bu/Ac)
Dry Year
WUE,(bu/in)H20
Wet Year
WUE,(bu/in)H20
0
75
96
4.82
4.68
150
114
152
7.48
6.98
N Response
(Bu/Ac)
39
56
Difference of
2.66 bu/in H20
Difference of
2.30 bu/in H20
Nitrogen increases bushels of corn per inch of available
water, regardless of the amount of water.
Optimum fertility rates result in improved yields and WUE
Can it speed my crop up? Does this help my timing?
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Optimum Fertility to Stretch Moisture
Helps produce more crop per inch of water
Sends roots deeper to find moisture in subsoil
Deeper, more dense root systems take up more water and nutrients
Creates a larger, thicker canopy faster to reduce soil evaporation
Better vegetation slows runoff and enables soil to soak up water
Helps crops start fast to shade out moisture-robbing weeds
“The greatest yield increase from fertilizers, percentage-wise,
frequently occur in years of moisture stress”
-International Plant Nutrition Institute
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New hybrids need more N post-flower
Obs
N @ R1
N @ R6
Post
Flowering
N Uptake
Old (1970)
37
125
162
37
New (2000’s)
52
125
177
52
Era of Hybrid
Release
40% increase in post-tassel N requirement
New hybrids are bringing in N later than old hybrids.
Our N management needs to change to meet crop demand changes.
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Factors Affecting Nitrogen
Factors Affecting Nitrogen
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Nitrogen Uptake in Corn
0.014
0.012
grain
cob
husk
emb. ears
tassel
stalk
leaf sheath
leaf
root
seed
65% of N has been taken up at Tassel
0.01
0.008
0.006
0.004
0.002
0
V1
V3
V5
V7
V9
V11
V13
V15
V17
R1
R3
R5
Lbs N/plant
0.018
0.016
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Courtesy of Paul Wayland, Wilbur-Ellis Co.
Corn Fertility Management Ladder
Lbs N/Bu
0.8
Pre-Plant NPK Band + Starter + Side-Dress +
Fertigation 50% NH3 + 50% UAN
Step 4
0.9
Pre-Plant NPK band + Starter + SideDress 50% NH3 + 50% UAN
1.0
50% Pre-Plant NH3 + 50% Side-Dress N; Pre
broadcast P&K Sidedress NH3 or UAN
1.1
Preplant Broadcast P&K +100%
Fertigation on N-100% N as UAN
1.2
100% Pre-Plant NH3 + Pre-Plant Broadcast
P&K
100% Pre-Plant Broadcast NPK; N 100% urea
Step 3
Step 1
Floor
Efficiency Rating
Step5
1.3
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Center Pivot applied UAN post
tassel
Photo by Alyssa Abbott
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Pioneer LJK Account
Manager
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Summary
Use Conservation tillage to preserve moisture
Planting Dates and Planting Rates should be matched to situation
and can be adjusted according to conditions
Irrigation timing – ET approach is easier and more predictable than
trying to push water to critical time periods – Banking water early
sends the wrong signal to the corn plant that everything is going to
be fine.
Proper Fertility balance is key to water use efficiency
Split applying nitrogen improves Nitrogen Use Efficiency and
reduces risk, but requires more management
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Thank You
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