Agronomic Implications of Soybean Rust

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• Agronomic Implications of Soybean Rust
• Shawn P. Conley
• Ellsworth ChristmasPurdue UniversitySoybean
  Production Systems

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2005 Soybean Production Q A

• Should I plant soybean earlier?
• Should I plant an earlier maturing cultivar?
• Should I modify my row spacing seeding rate?

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2005 Soybean Production Q A

• Should I plant all corn in 2005?
• Will rust affect double crop beans more than the
  full season varieties?
• Can I tank mix glyphosate with a fungicide?

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Should I Plant Soybean Earlier in 2005?
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Floral initiation

• Photoperiod Short day/critical value to initiate
  floral induction
• Temperature regulates when flowers appear

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Effect of Early Planting Date on Soybean Yield,
Davis PAC, 1991
? 21
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Effect of Early Planting Date on Soybean Yield,
SEPAC, 1991
? 31
? 21
? 4
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Effect of Early Planting Date Soybean Yield,
SEPAC, 1992

? 24
? 7
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Soybean Yield Response to Planting Date 1991-94
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Soybean Yield Response to Planting Date 1991-94
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Should I Plant an Earlier Maturing Cultivar in
2005?
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Effect of Maturity on Yield
-----------Grain Yield ----------- -----------Grain Yield ----------- -----------Grain Yield -----------
Region M.G. Maturity 2004 03-04 02-04
2 2 9/13 64.4 55.3 57.2
2 3 9/21 67.6 58.9 59.6

3 2 9/04 62.5 58.2 59.3
3 3 9/14 65.1 62.7 63.3
3 4 9/22 65.4

4 3 9/19 61.8 56.2 51.2
4 4 9/28 64.8 57.4 52.7
2004 UI Variety Testing
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Implications for Early Variety

• Matured an average of 9 days earlier
• Average 4.5 yield loss
• 3 bushel yield loss _at_ 5.00 to 6.00
• 15.00 to 18.00 for a fungicide application
• Risk assessment 9 days vs. 18.00

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Should I Modify My Row Spacing and Seeding Rate?
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8 ?
3 ?
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Wheel Traffic Effect on Soybean Yield
--------------Grain Yield -------------- --------------Grain Yield -------------- --------------Grain Yield -------------- Estimated yield loss Estimated yield loss
Center row Wheel track row Adjacent row 40 ft. boom 90 ft. boom
------------------------------bushel a-1 ------------------------------ ------------------------------bushel a-1 ------------------------------ ------------------------------bushel a-1 ------------------------------ ------------------------------bushel a-1 ------------------------------ ------------------------------bushel a-1 ------------------------------
2 (VC) 56.9 37.3 61.6 0.3 0.1
3 (V1) 57.2 36.7 62.0 0.3 0.1
4 (V2-4) 58.0 34.7 63.1 0.4 0.2
5 (V4-5) 59.6 31.5 64.8 0.5 0.2
6 (V7-R1) 61.8 26.9 67.2 0.6 0.3
2,4 59.6 25.4 67.6 0.7 0.3
3,5 59.8 24.8 68.0 0.7 0.3
4,6 60.7 22.9 69.0 0.7 0.3
Piper, Swearingin, Nyquist. 1989.
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Increased Income Compared to Increased Seed Cost
for Solid Seeded Soybeans
Seeding rate comparison Increased seed cost/A 2800 seeds/lb (140 k) Increased seed cost/A 2800 seeds/lb (140 k) Increased seed cost/A 2800 seeds/lb (140 k) Increased Income /A Increased Income /A
20/unit 25/unit 30/unit 5.00/bu 6.00/bu
200 to 300 14.29 17.86 21.43 7.00 8.40
200 to 250 7.14 8.93 10.71 4.50 5.40

150 to 300 21.43 26.79 32.14 13.50 16.40
150 to 250 14.29 17.86 21.43 11.00 13.80
150 to 200 7.14 8.93 10.71 6.50 7.80
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Increased Income Compared to Increased Seed Cost
for Solid Seeded Soybeans
Seeding rate comparison Increased seed cost/A 3200 seeds/lb (160 k) Increased seed cost/A 3200 seeds/lb (160 k) Increased seed cost/A 3200 seeds/lb (160 k) Increased Income /A Increased Income /A
20/unit 25/unit 30/unit 5.00/bu 6.00/bu
200 to 300 12.50 15.63 18.75 7.00 8.40
200 to 250 6.25 7.81 9.38 4.50 5.40

150 to 300 18.75 23.44 28.13 13.50 16.40
150 to 250 12.50 15.63 18.75 11.00 13.80
150 to 200 6.25 7.81 9.38 6.50 7.80
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Should I Plant all Corn in 2005?
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Corn Yield Response to Tillage and Rotation from
1975 to 2004 in West Lafayette, IN (Chalmers
silty clay loam)
1975-2003 1975-2003 2004 2004 Yield Gain for Rotation () Yield Gain for Rotation ()
Tillage system C/S CC C/S CC 75-03 2004
---------Yield (bu/acre)--------- ---------Yield (bu/acre)--------- ---------Yield (bu/acre)--------- ---------Yield (bu/acre)---------
Moldboard 176.4 168.5 213 201 5 6
Chisel Plow 176.9 164.0 209 198 8 5
No-till 172.5 146.2 207 179 18 16
T.D. West, T.J. Vyn, G. Steinhardt
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Corn Yield Response to Tillage and Rotation from
1997 to 2004 in Wanatah, IN (Sebewa loam)
1997-2003 1997-2003 2004 2004 Yield Gain for Rotation () Yield Gain for Rotation ()
Tillage system C/S CC C/S CC 97-03 2004
---------Yield (bu/acre)--------- ---------Yield (bu/acre)--------- ---------Yield (bu/acre)--------- ---------Yield (bu/acre)---------
Moldboard 188 174 230 210 8 9
Chisel Plow 189 170 234 211 11 11
No-till 184 161 224 206 14 9
T.D. West, T.J. Vyn, G. Steinhardt
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Factors to Consider in Continuous Corn

• ? Yield loss (11 to 23 bushels in 2004)
• Higher tillage costs No-till ineffective
• Associated higher soil erosion costs
• Higher optimum N rates ( 40 units N)
• Pest control may now be a wash

T.D. West, T.J. Vyn, G. Steinhardt
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Will rust affect double crop beans more than the
full season varieties?
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10
8
5
3
Average Date For the Start of Wheat Harvest
July June
30
28
26
24
22
21
20
19
18
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Average Indiana Soybean Development
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Increased Double Crop Risk?

• Vegetative versus reproductive stage
• Increased risk of early infection
• Multiple applications may be required
• Open canopy and airflow considerations?
• Yield potential versus increased risk?

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Can I Tank Mix Glyphosate With a Fungicide?
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Factors to Consider

• Drift and Nozzle Selection
• Droplet size and Pressure
• Herbicide gt 400 µm and low pressure
• Fungicide lt 220 µm and higher pressure
• Timing Herbicide vs. fungicide
• Glyphosate 4 to 6 for annuals 6 to 12
  perennials up to 50 bloom
• Fungicide R1 and later
• Label Issues Tank mix partners? Vague

Fungicides, Herbicides, and Soybean Rust, Do they
Mix?
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Questions?conleysp_at_purdue.edu