Corn After Corn: Agronomic and Farm Management Considerations
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Transcript of Corn After Corn: Agronomic and Farm Management Considerations
Corn After Corn: Agronomic and Farm Management Considerations
Bruce EricksonDepartment of Agricultural Economics
Certified Professional Agronomist
Learning Tuesday Session, February 20, 2007 2
Why More Corn Acres?
• Demand from Ethanol Production• Long-Term Yield Trend Favoring Corn• South American Soybean Production Influencing
Prices• Soybean Pest Concerns• Rotation Not Controlling Rootworms in E. Corn
Belt• Decrease in Price Ratio Soybeans/Corn
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0
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1965 1970 1975 1980 1985 1990 1995 2000 2005
Yield, bu/A
U.S. Yield Trends
CORN
SOYBEANS
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South American Soybean Production Outpacing U.S.
Chicago Board of Trade
Learning Tuesday Session, February 20, 2007 5
Soybean Pest Concerns
• Sudden Death Syndrome• Soybean Cyst Nematode• Soybean Aphids• Asian Rust
In the past it was rare to treat for anything in-season for soybeans—Soybean Aphids have changed that paradigm
Soybean Aphids
Learning Tuesday Session, February 20, 2007 6
Corn Rootworm RiskCorn After Soybeans
Purdue Department of Entomology
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Returns Are Affected By
• Ratio of corn yield to soybean yield
• Ratio of corn price to soybean price
• Input cost differences
• Timeliness issues
• Ability to put the management pieces together to develop the system
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Shnitkey, Univ. of Illinois, Farm Economics Facts and Figures, 2006
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Ratio of Corn to Soybean Acres (2005)
Shnitkey, Univ. of Illinois, Farm Economics Facts and Figures, 2006
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Uni
vers
ity C
rop
Rot
atio
n R
esea
rch
Primary Author, Year Location Study Years Rotation vs. Cont Corn %
Crookston 1991 Lamberton & Waseca, MN 1981-1989 9
Edwards 1988 Crossville, AL 1981-1984 -24
Griffith 1988 Butlerville, IN 1980-1986 -7
Howard 1998 Grand Jct., TN 1986-1992 11
ISU, 2002 Nashua, IA 1979-1998 12
Katsvairo 2000 Aurora, NY 1993-1997 19
Lauer 1997 Lamberton and Waseca, MN, Arlington, WI 1981-1996 13
Lee 2004 Lexington, KY 1984-1997 9
Lund 1993 Arlington, WI 1989-1991 8
Meese 1991 Arlington, WI 1987-1989 16
Pedersen 2002 Arlington, WI 1995-1997 13
Pedersen 2003 Arlington, WI 1998-2001 15
Peterson 1989 Mead, NE 1983-1986 12
Porter 1997 Lamberton, MN 1985-1995 13
Porter 1997 Waseca, MN 1986-1995 10
Porter 1997 Arlington, WI 1987-1995 16
Riedell 1998 Brookings, SD 1994-1995 11
Singer 1998 Aurora, NY 1993-1994 5
Singer 2003 Pittstown, NJ 2000-2001 2
Univ. of IL Ext., 2002 IL 17 Site years 18
Varvel 2003 Shelton, NE 1993-2003 3
Varvel 2003 Mead, NE 1983-2003 3
Vyn 2004 Wanatah, IN 1997-2004 8
Vyn 2004 West Lafayette, IN 1975-2004 8
Walters 2004 Mead, NE 1999-2004 3
Wilhelm 2004 Mead, NE 1986-2001 23
Rot
atio
n C
orn
+9%
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Variable Costs of Corn After Corn
Learning Tuesday Session, February 20, 2007 12
Economics of Corn After Corn
• Higher Input Costs– Fertilizer, especially nitrogen– Tillage– Somewhat higher seed costs– Higher pest control cost (rootworm, etc.)
• Increased Timeliness Constraints at Planting
• Decreased Timeliness Constraints at Harvest
• Greater Machinery Costs
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Rotation Options
• Corn/Soybean
• Corn/Corn/Soybean
• Some Acres Corn/Soybean, Some Continuous Corn
• Many others
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Linear Programming Analysis
• If it costs more to grow continuous corn, what grain price advantage for corn, or how much more corn yield will it take for continuous corn to occupy more of your farm’s acres?
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Continuous Corn Model for Linear Programming
• 3000 acre farm• 2 full-time employees, 6 part-time employees• 3 large tractors, 2 small tractors• 42-ft disk and field cultivator, mini-moldboard plow• 24-row planter• 12-row corn head; 30-ft platform soybean head• 400,000 bushel on-farm grain storage• Purdue B-21 linear programming analysis has been
used for nearly 30 years on over 7000 farms to assist farm-level decisions; Also used in published research, master’s and doctoral dissertations
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Key Linear PC-LP Results
• Higher Machinery Costs
• Greater Constraints at Planting Time
• Relaxed Constraints at Harvest
• Continuous corn must yield substantially more, or soybean/corn price ratio must be small enough to justify
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What Corn/Soybean Price Ratio Justifies Continuous Corn?
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Acres Planted
2.23 2.32 2.42 2.52 2.64 2.76 2.90 3.05 3.22
Corn Prices
Rot.SoybeansRot. Corn
Cont. Corn
Cont. Corn Yield 215 bu/A 2.5 2.2 1.9
Robertson, 2006Soybean/Corn Price Ratio
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Agronomics for Corn on Corn
• Choose Best Fields• Increase N fertilizer• Plan for Rougher, Cooler Seedbeds
– Planting rates– Tillage– Plant after corn following soybean fields
• Increased threat of leaf disease– Hybrid selection– Fungicide
• Different insect threat– Rootworms primary threat—genetic and chemical options– Little difference in corn borers or seed-attacking insects
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Rotation Yield Difference by Yield Level (4-year study, U of MN)
Yield LevelBu/A
Yield Difference Bu/A
% Difference
110 32 29
120 17 14
140 24 17
155 25 16
165 12 7
180 5 3
200 5 2.5
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Corn Yield Response to Nitrogen Fertilizer
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Rate of Nitrogen (lbs./acre)
Yie
ld (
bu
./a
cre
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Corn After Corn Yield Response
Linear (N/Corn Price Ratio = .085)
Linear (N/Corn Price Ratio = .2)
EO
NR
EO
NR
Determining the Economically Optimum Nitrogen Rate
Optimum N occurs where marginal value of adding another lb. of N just equals the marginal cost of adding another lb. of N
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Response to Tillage and Rotation1975-2006, West Lafayette
Corn/
Soy
Corn/
Corn
Gain for Rotation
Moldboard Plow
180 172 4%
Chisel Plow 180 168 7%
No-Till 175 150 18%
Vyn, 2006
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Increased Threat of Leaf Disease
• Anthracnose
• Eyespot
• Gray leaf spot
• Northern Corn Leaf Blight
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Rootworms Primary Insect Threat
• Western Rootworm Variant has changed rotation dynamics
• Genetic options for rootworms are excellent option
• Seed treatments for rootworms only effective with light pressure
• Threat of corn borers and seed-attacking insects not drastically different
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Corn on Corn Hybrid Selection
• Emergence, seed quality
• Early Growth
• High Residue Suitability
• Leaf and Stalk Disease Ratings
• Standability, resistance to stalk lodging and root lodging
• Insect Resistance ratings, and Insect Traits
• Herbicide Resistance traits, depending on weed management program
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Effect of Post Spray Timing on Weed Control and Yield (Michigan State University)
Weed size at application
Weed Control%
Corn Yield LossFrom Early Season Weed
Competition, %
2” 73 0
4” 83 3
6” 90 6
9” 93 14
12” 95 22
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Is There an Advantage for Long-Term Continuous Corn?
• Many successful continuous corn growers have developed a management scheme of interrelated practices
• Some say it is difficult to test systems approaches using traditional agronomic testing principles
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Continuous Corn/High Yields
• Herman Warsaw, Illinois – 1970s, >300 bu/A
• Francis Childs, Iowa– 1990s, >400 bu/A
• Mark Dempsey, Illinois– 2004 Illinois NCGA Champ,
320 bu/A
• 2005 and 2006 NCGA results
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Perceived Yield Differences
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0 1 2 3 4 5 6 7 8 9 10
Years After Last Soybean Crop
bu
/A
Corn After Soybeans
Cont. Corn/Research
Cont. Corn/Farmers
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Long-Term Continuous Corn
• Increases in Organic Matter
• Increases in Available Nitrogen
• Improvements in Soil Quality
• Dobermann, Nebraska:
– Corn/soybean systems exploit soil C and N
– Continuous corn systems have the potential to build C and N
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Farmer Experiences From Long-Term Continuous Corn
• Very High Rates of N, P, and K
• High Planting Rates
• Attention to Hybrid Selection (Disease & Insect)
• Good Field Drainage
• Fall-Applied Nitrogen
• Intensive Tillage
• Many of the management practices for continuous corn are the same as they are for corn following soybeans
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Take-Home Messages
• Input costs and ratio of corn price to soybean price and yields key determinants of decision
• Successfully growing continuous corn may require:– More intensive tillage– Higher rates of fertilizer– Careful attention to plant genetics– Ability to manage a system as much as individual
components
Top Farmer Crop WorkshopJuly 22-25, 2007
West Lafayette
Bruce EricksonDepartment of Agricultural Economics
Purdue University (765)494-9557
[email protected]@purdue.eduhttp://www.purdue.edu/ssmc/http://www.purdue.edu/ssmc/
http://www.agecon.purdue.edu/topfarmer/http://www.agecon.purdue.edu/topfarmer/