Corn After Corn: Agronomic and Farm Management Considerations

1. Corn After Corn: Agronomic and Farm Management Considerations Bruce Erickson Department of Agricultural Economics Certified Professional Agronomist

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

3. U.S. Yield Trends CORN SOYBEANS

4. South American Soybean Production Outpacing U.S. Chicago Board of Trade

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

6. Corn Rootworm RiskCorn After Soybeans Purdue Department of Entomology

7. 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

8. Shnitkey, Univ. of Illinois, Farm Economics Facts and Figures, 2006

9. Ratio of Corn to Soybean Acres (2005) Shnitkey, Univ. of Illinois, Farm Economics Facts and Figures, 2006

10. University Crop Rotation Research Rotation Corn +9%

11. Variable Costs of Corn After Corn

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

13. Rotation Options • Corn/Soybean • Corn/Corn/Soybean • Some Acres Corn/Soybean, Some Continuous Corn • Many others

14. 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?

15. 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

16. 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

17. What Corn/Soybean Price Ratio Justifies Continuous Corn? Cont. Corn Yield 215 bu/A 2.5 2.2 1.9 Soybean/Corn Price Ratio Robertson, 2006

18. 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

19. Rotation Yield Difference by Yield Level (4-year study, U of MN)

20. Optimum N occurs where marginal value of adding another lb. of N just equals the marginal cost of adding another lb. of N EONR EONR Determining the Economically Optimum Nitrogen Rate

22. Response to Tillage and Rotation1975-2006, West Lafayette Vyn, 2006

23. Increased Threat of Leaf Disease • Anthracnose • Eyespot • Gray leaf spot • Northern Corn Leaf Blight

24. 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

25. 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

26. Effect of Post Spray Timing on Weed Control and Yield (Michigan State University)

27. 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

28. 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

29. Perceived Yield Differences

30. 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

31. 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

32. 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

33. Top Farmer Crop Workshop July 22-25, 2007 West Lafayette

34. Bruce EricksonDepartment of Agricultural EconomicsPurdue University (765)494-9557 berickso@purdue.edu http://www.purdue.edu/ssmc/ http://www.agecon.purdue.edu/topfarmer/