Agronomic Implications of Soybean Rust Shawn P. Conley
Ellsworth Christmas Purdue University Soybean Production
Systems
Slide 2
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?
Slide 3
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? 2005 Soybean Production Q & A
Slide 4
Should I Plant Soybean Earlier in 2005?
Slide 5
Floral initiation Photoperiod: Short day/critical value to
initiate floral induction Temperature regulates when flowers
appear
Slide 6
Effect of Early Planting Date on Soybean Yield, Davis PAC, 1991
21%
Slide 7
Effect of Early Planting Date on Soybean Yield, SEPAC, 1991 31%
21% 4%
Slide 8
Effect of Early Planting Date Soybean Yield, SEPAC, 1992 24%
7%
Slide 9
Soybean Yield Response to Planting Date 1991-94
Slide 10
Slide 11
Should I Plant an Earlier Maturing Cultivar in 2005?
Slide 12
Effect of Maturity on Yield -----------Grain Yield -----------
RegionM.G.Maturity200403-0402-04 229/1364.455.357.2
239/2167.658.959.6 329/0462.558.259.3 339/1465.162.763.3
349/2265.4** 439/1961.856.251.2 449/2864.857.452.7 2004 UI Variety
Testing
Slide 13
Implications for Early Variety Matured an average of 9 days
earlier Average 4.5% yield loss 3 bushel yield loss @ $5.00 to
$6.00 $15.00 to $18.00 for a fungicide application Risk assessment:
9 days vs. $18.00
Slide 14
Should I Modify My Row Spacing and Seeding Rate?
Slide 15
8% 3%
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Wheel Traffic Effect on Soybean Yield --------------Grain Yield
--------------Estimated yield loss Center row Wheel track row
Adjacent row 40 ft. boom 90 ft. boom
------------------------------bushel a -1
------------------------------ 2 (VC)56.937.361.60.30.1 3
(V1)57.236.762.00.30.1 4 (V2-4)58.034.763.10.40.2 5
(V4-5)59.631.564.80.50.2 6 (V7-R1)61.826.967.20.60.3
2,459.625.467.60.70.3 3,559.824.868.00.70.3 4,660.722.969.00.70.3
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 Income $/A
$20/unit$25/unit$30/unit$5.00/bu$6.00/bu 200 to
30014.2917.8621.437.008.40 200 to 2507.148.9310.714.505.40 150 to
30021.4326.7932.1413.5016.40 150 to 25014.2917.8621.4311.0013.80
150 to 200 7.14 8.9310.716.50 7.80
Slide 18
Increased Income Compared to Increased Seed Cost for Solid
Seeded Soybeans Seeding rate comparison Increased seed cost/A 3200
seeds/lb (160 k) Increased Income $/A
$20/unit$25/unit$30/unit$5.00/bu$6.00/bu 200 to
30012.5015.6318.757.008.40 200 to 2506.257.819.384.505.40 150 to
30018.7523.4428.1313.5016.40 150 to 250 12.50 15.6318.7511.00 13.80
150 to 200 6.25 7.819.38 6.507.80
Slide 19
Should I Plant all Corn in 2005?
Slide 20
Corn Yield Response to Tillage and Rotation from 1975 to 2004
in West Lafayette, IN (Chalmers silty clay loam) 1975-20032004Yield
Gain for Rotation (%) Tillage systemC/SCCC/SCC75-032004
---------Yield (bu/acre)--------- Moldboard176.4168.5213201 56
Chisel Plow176.9164.0209198 85 No-till172.5146.2207179 1816 T.D.
West, T.J. Vyn, G. Steinhardt
Slide 21
Corn Yield Response to Tillage and Rotation from 1997 to 2004
in Wanatah, IN (Sebewa loam) 1997-20032004Yield Gain for Rotation
(%) Tillage systemC/SCCC/SCC97-032004 ---------Yield
(bu/acre)--------- Moldboard188174230210 89 Chisel Plow189170234211
11 No-till184161224206 149 T.D. West, T.J. Vyn, G. Steinhardt
Slide 22
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
Slide 23
Will rust affect double crop beans more than the full season
varieties?
Slide 24
10 8 5 3 30 July June 28 26 24 22 21 20 19 18 Average Date For
the Start of Wheat Harvest
Slide 25
Average Indiana Soybean Development
Slide 26
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?
Slide 27
Can I Tank Mix Glyphosate With a Fungicide?
Slide 28
Factors to Consider Drift and Nozzle Selection Droplet size and
Pressure Herbicide: > 400 m and low pressure Fungicide: < 220
m 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?
