Impacts of Changing Seeding Rates in Soybean• Weeds are the #1 IN soybean pest • Glyphosate...
Transcript of Impacts of Changing Seeding Rates in Soybean• Weeds are the #1 IN soybean pest • Glyphosate...
Impacts of Changing SeedingImpacts of Changing SeedingRates in SoybeanRates in Soybean
Shawn P. Conley Shawn P. ConleySoybean Extension SpecialistSoybean Extension Specialist
Purdue UniversityPurdue University
What is Driving ReducedSoybean Seeding Rates?
• Growing cost concerns:• Seed cost RR - 2007
• List price – $30.99 to 33.99• Farm gate – $23.50 to 26.50
• Non GMO• List price – ~$21.00• Farm gate – ~$15.00
• Seed treatment cost - 2007• Fungicide ~ $2.50 to $3.00• Insecticide + fungicide ~ $9.50
• What is it cheaper to do?• Plant more seeds or treat seed
Good Thing All Universities Agree!!
-----------Seeds or plants acre-1 -----------
119 to 179139 to 167111 to 13980%Kentucky-plants175 to 280139 to 174122 to 15790%Michigan-seeds200,000175,000140,00090%Missouri-seeds
---Wisconsin196,000160,000129,00090*90%Indiana-seeds196,000160,000129,00090*90%Ohio-seeds
90%
Germination -----Recommended Seeding Rates -----
125 to 140-
15”
200*125 to 140Iowa-seeds--Illinois
7.5”30”State
*Old versus new
What Else is Driving ReducedSoybean Seeding Rates?
• Farm equipment changes (farm size and technology)• Growers giving up the drill
• Uniformity in seed placement and emergence
• What is your average seeding rate by row spacing?
196,000
160,000
129,000
Purdue rec’s(90*90)
57%198,000≤ 10 in.
31%180,00011 ≥ x ≤ 20
12%155,000≥ 21 in.
% respondentsSeeding rateRow spacing
Conley and Santini, 2007
Common Questions Related to Variety Selection inReduced Soybean Seeding Rate Systems
• Variety selection – Is it important?
• Erect vs. bushy response to reducedplant populations or row spacing
• Real or marketing/grower perception?
• What about maturity group response?• Should I tweak my population based on
maturity group adaptiveness?
Soybean Variety Selection• Independent of farm size 28, 25, 29, and 18% of growers planted 1, 2, 3-
4, or ≥ 5 varieties of soybean in 2005.
• 55% of growers with 1000+ acres planted 4 or less varieties
2.32.22.22.12.3Seed Dealer
1.61.71.71.71.6Disease Resistance
1.81.81.51.61.5RR ® Ready Trait
1.21.41.41.41.5Yield Potential
3.23.13.03.12.9Grain Quality Traits
2.62.72.62.82.7Seed Company
2.42.52.42.52.3Seed Price
---------------------------------Rank (1-5)----------------------------------
1000+500 - 999250 – 499100 - 2490 - 99Grain Yield
---------------------------- Farm size (acres) ----------------------------
Conley and Santini, 2007
Maturity Group and Stem Phenotype Response toDecreased Soybean Populations
• Northern:• 2.8 and 3.6 M.G
• Southern:• 3.6 and 4.2
• Plant populations• 50,000 to 250,000
• Erect vs. bushy beans
• 10 site years; 4 varieties
• Drilled soybean (7.5”)
Impact of plant population on soybean yield
40.0
45.0
50.0
55.0
60.0
65.0
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0 50,000 100,000 150,000 200,000
Stand Population
Yie
ld
ACRE NEPAC PPAC SEPAC
Does Planting Date Impact My Decision toReduce My Soybean Seeding Rate
Defining Planting Date Responses in Illinois*2001-2003 University of Illinois CMRA Project
-------------------- bushel/acre --------------------
46.648.948.945.3225
46.548.348.743.8175
46.547.648.341.9125
43.546.645.838.775
Late MayEarly MayLate AprilEarly April000/acre
Planting dateSeed rate†
*Soybean yield averaged over nine environments in Northern Illinois.†Seeding rates are expressed as viable seeds per acre.
Defining Planting Date Responses in Illinois*2001-2003 University of Illinois CMRA Project
-------------------- bushel/acre --------------------
33.734.635.432.9225
32.436.334.632.3175
32.835.333.729.3125
30.635.933.730.475
Early JuneLate MayEarly MayMid-April000/acre
Planting dateSeed rate†
*Soybean yield averaged over four environments in Southern Illinois.†Seeding rates are expressed as viable seeds per acre.
• “In Northern Illinois….Planting in early Aprilreduced yield by about 10 percent, and planting inlate May reduced yield by about 5 percent; theseresults suggest that planting “too early” tends toreduce yield more than planting late.”
• “It pays to wait to plant, but if planting is earlierthan ideal, it pays to add extra seed.”
Defining Planting Date Responses in Illinois2001-2003 University of Illinois CMRA Project
Emerson D. NafzigerUniversity of Illinois
• “In Northern Illinois….Optimum planting rates forplanting in the optimum window were about150,000 to 160,000 viable seeds per acre, but thisrose to above 200,000 per acre if planting wasearlier than the optimum time.”
• “Still it appears that planting rate should bebetween 150,000 to 175,000 viable seeds peracre in Southern Illinois.”
Defining Planting Date Responses in Illinois2001-2003 University of Illinois CMRA Project
Emerson D. NafzigerUniversity of Illinois
Does Row Spacing Impact My Decision toReduce My Soybean Seeding Rate
0
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20
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Bu/Ac
Seeding Rate (1000’s)250 220 190 160 130 100
167 159138
116 106
70
Harvest Pop
Yield
High Yield EnvironmentHigh Yield Environment
Should Yield Environment Affect Seeding RateShould Yield Environment Affect Seeding Rate
0
50
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$
Seeding Rate (1000’s)
$ of Yield
Seed Cost ($)
Profit
250 220 190 160 130 100
Max
Economic Analysis for a High Yield Field
0
10
20
30
40
50
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Bu/Ac
Seeding Rate (1000’s)250 220 190 160 130 100
225 204175
150108
78
Harvest Pop
Yield
Should Yield Environment Affect Seeding RateShould Yield Environment Affect Seeding Rate
Moderate Yield EnvironmentModerate Yield Environment
0
50
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$
Seeding Rate (1000’s)
$ of Yield
Seed Cost ($)
Profit
250 220 190 160 130 100
Max
Economic Analysis for a Medium Yield Field
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10
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30
40
50
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Bu/Ac
Seeding Rate (1000’s)250 220 190 160 130 100
197177
154
131
92 65
Harvest Pop
Yield
Should Yield Environment Affect Seeding RateShould Yield Environment Affect Seeding Rate
Low Yield EnvironmentLow Yield Environment
0
50
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150
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$
Seeding Rate (1000’s)
$ of Yield
Seed Cost ($)
Profit
250 220 190 160 130 100
Max245
Economic Analysis for a Low Yield Field
• Weed control implications• Weeds are the #1 IN soybean pest• Glyphosate resistance is a reality• Delayed canopy closure as row spacing increases
65707530404550152530357.5
5/16 to 5/255/6 to 5/15< 5/5----------May planting date ----------Row Spacing
Common Questions Related to Weed Management inReduced Soybean Seeding Rate Systems
Soybean Yield Loss Influenced by the Timing of
Weed Removal and Row Spacing
0
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V1 V2 V3 V4 V5 V6 V7 R1 R2 R3
Timing of weed removal (Soybean growth stage)
Yie
ld L
os
s (
% w
ee
d f
ree
)
7.5"
15"
30"
Knezevic et al. 2003.
Weed Management in GR Soybean
• 26% of respondents indicated that they applied apreemergence herbicide to their soybean crop.
• 23% of growers indicated that they utilized a one passweed control program.
• The percentage of growers utilizing a one trip weedcontrol programs was 40% (99 or less), 34% (100 to249), 20% (250 to 499), 13% (500 to 999), and 11%(1000+).
• One pass program produced a 5.8% yield losscompared to those growers with 2+ passes.
Johnson et al. 2007
What is the Take Home Message
• Growers are slowly backing off seeding rates• Driven by seed cost and equipment changes
• Variety selection based on yield potential and defensive traits isimportant; canopy architecture is not important
• Planting date will affect seeding rate• Critical factor is getting a base population ≥ 100,000
• Row spacing and environment factors are related to maximizingleaf area
• Don’t forget about weed competition and glyphosate resistance• (Weed Scientists aren’t that bad after all)
Acknowledgements
• Nicole Fink – Purdue University• Emerson Nafziger – University of Illinois• Seth Naeve – University of Minnesota• Jim Beuerlein – The Ohio State University• Paul Carter - Pioneer Hi-Bred International• Kevin Cavanaugh – Beck’s Superior Hybrids
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