1. Chad Lee Grain Crops Extension 859-257-3203 cdlee2@uky.edu 1 Univ. of Kentucky, Grain Crops Extension © 2008

2.  Soil temperature  Soil moisture  Seeding depth  Seed spacing 2 Univ. of Kentucky, Grain Crops Extension © 2008

3.  Planting too early or too late can reduce yields Univ. of Kentucky, Grain Crops Extension © 2008 3

4.  50 O F at a 2-inch depth for three or four days is excellent.  Soil temperature at 50 O F at 7:00 am or 55 O F at 1:00 pm 4

5. Univ. of Kentucky, Grain Crops Extension © 2008 5 TownCoordinancesDate of Last Spring Occurrence of 32° F a,b (°)MedianEarly10%90%Late Owensboro 37.77N 87.11W 4/103/213/254/245/05 Paducah 37.08N 88.62W 4/083/073/224/184/23 Lexington 38.03N 84.44W 4/183/264/045/035/10 Princeton 37.09N 87.89W 4/103/213/264/213/26

6. Univ. of Kentucky, Grain Crops Extension © 2008  Planting Date: April 1 – May 1 (central and western KY) April 15 – May 15 (eastern KY) 6

7. Average Planting Date Corn Yield (Bu/Acre)* (6 -Yr Avg.) (2000 - 2005) Avg. Loss (Bu/A) April 7196-14 April 222100 May 9193-17 May 24172-38 June 9130-80 *Average of 2 hybrids (Bt & Non-Bt) Univ. of Kentucky, Grain Crops Extension © 2008 7 J. Herbek and R. Bessin

8. Average Planting Date Corn Yield (Bu/A) (2000-2005) Bt Hybrid Advantage (Bu/A) Non-Bt HybridBt Hybrid April 7195197+2 April 22208211+3 May 9189196+7 May 24167178+11 June 9118141+23 Univ. of Kentucky, Grain Crops Extension © 2008 8 Herbek and Bessin

9. Average Planting Date Corn Yield (Bu/Acre)* (6 -Yr Avg.) (2000 - 2005) Avg. Loss (Bu/A) April 7196-14 April 222100 May 9193-17 May 24172-38 June 9130-80 *Average of 2 hybrids (Bt & Non-Bt) Univ. of Kentucky, Grain Crops Extension © 2008 9 J. Herbek and R. Bessin

10.  Optimum Corn Yields: mid-late April  Yields declined: after May 1  Early May: Critical planting date for yield. In 3 of 6 years, yields declined. Other 3 years, had no yield loss. Univ. of Kentucky, Grain Crops Extension © 2008 10 Lexington, KY: Optimum planting for corn: May 1 - 7 Herbek and Bessin

11.  Princeton  Lexington May 1 - 7 April 19 - 25 11 Univ. of Kentucky, Grain Crops Extension © 2008

12.  Princeton  Lexington  Owensboro? May 1 - 7 April 19 - 25 12 Univ. of Kentucky, Grain Crops Extension © 2008

13. 13 PlantingHendersonPrinceton DateAug 31 GDD Mar. 1, 200735313816 Apr. 5, 200731883364 Apr. 20, 200731323255 About 2700 to 3000 GDD’s needed for blacklayer. TownCoordinancesDate of Last Spring Occurrence of 32° F a,b (°)MedianEarly10%90%Late Owensboro 37.77N 87.11W 4/103/213/254/245/05 Paducah 37.08N 88.62W 4/083/073/224/184/23 Lexington 38.03N 84.44W 4/183/264/045/035/10 Princeton 37.09N 87.89W 4/103/213/264/215/26

14. Univ. of Kentucky, Grain Crops Extension © 2008 14 Hybrid Maturity (GDD) Planting 240027003000 Kentucky Location Date Date to Reach Black Layer Mayfield 3/15 7/288/88/20 4/1 8/18/138/24 4/15 8/68/188/30 5/1 8/148/269/8 5/15 8/239/49/19 6/1 9/59/2010/11 Bowling Green 3/15 7/278/78/19 4/1 7/318/128/23 4/15 8/58/178/29 5/1 8/128/249/5 5/15 8/219/29/16 6/1 9/39/1810/7 Henderson 3/15 7/278/88/20 4/1 8/18/138/24 4/15 8/68/188/30 5/1 8/148/259/7 5/15 8/239/49/19 6/1 9/59/2010/9

15. Planting Date 1 WAP2 WAP3 WAP4 WAP Mar 1, 20072185115239 Mar 14, 200744168271 Apr 1, 20071566130247 Apr 15, 200764180312 Apr 20, 200712129260 Univ. of Kentucky, Grain Crops Extension © 2008 15 About 100 GDD’s needed for complete emergence. About 200 GDD’s needed for V2 (two fully emerged leaves).

16. Univ. of Kentucky, Grain Crops Extension © 2008 16 TownCoordinancesDate of Last Spring Occurrence of 32° F a,b (°)MedianEarly10%90%Late Owensboro 37.77N 87.11W 4/103/213/254/245/05 Paducah 37.08N 88.62W 4/083/073/224/184/23 Lexington 38.03N 84.44W 4/183/264/045/035/10 Princeton 37.09N 87.89W 4/103/213/264/215/26

17. Univ. of Kentucky, Grain Crops Extension © 2008  1 ½ to 2 inches (into moisture) Tips to Reduce Planter Performance Effects on Corn Yield AGF-150-01 Greg La Barge Extension Agent, Ohio State University Extension Dr. Peter Thomison Extension Specialist, Corn Production http://ohioline.osu.edu/agf-fact/0150.html 17

18. Univ. of Kentucky, Grain Crops Extension © 2008 18

19. Univ. of Kentucky, Grain Crops Extension © 2008 19

20. 20 Univ. of Kentucky, Grain Crops Extension © 2008

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22. Univ. of Kentucky, Grain Crops Extension © 2008 22 Low areas High Areas

23. Univ. of Kentucky, Grain Crops Extension © 2008 23  Tillage (only when necessary) Deep ripping – only to alleviate compaction, conduct when soil is dry to improve cracking of the compacted layer Avoid the moldboard plow – quickest way to destroy soil structure and organic matter  Exception: incorporate manure Use chisel plow or field cultivator, avoid powdering the soil surface

24. Univ. of Kentucky, Grain Crops Extension © 2008 24  Tillage – compaction concern Most likely to compact soil when tillage is conducted one day before soil is dry enough  No-tillage – typically recovers from compaction quicker than tilled soils Compaction can and does occur in no-till, still need to be cautious

25. Univ. of Kentucky, Grain Crops Extension © 2008 25 Organic Matter and Soil Compaction G. Schwab

26. Spacing Between Rows (inches) Plant Population (plants/acre) Spacing Within Rows (inches) 3030,0007.0 3024,0008.7 Univ. of Kentucky, Grain Crops Extension © 2008 26 Variability up to 2 inches does not hurt yields. Variability above 2 inches will reduce yields. R.L. Nielsen

27. Spacing Between Rows (inches) Plant Population (plants/acre) Spacing Within Rows (inches) Allowable Within Row Spacing (inches) 3030,0007.05.0 - 9.0 3024,0008.76.7 - 10.7 Univ. of Kentucky, Grain Crops Extension © 2008 27 Variability up to 2 inches does not hurt yields. Variability above 2 inches will reduce yields. R.L. Nielsen

28. Univ. of Kentucky, Grain Crops Extension © 2008 28 4.5 mph 7.0 mph 3 locations in Ontario, Canada 2 years 28,900 seeds/acre * Sig. Difference between speeds Tollenaar et al. 2004. Agron. J. 96:1668-1672 * * * * * * * * *

29. Univ. of Kentucky, Grain Crops Extension © 2008 29 Lauer and Rankin. 2004. Agron. J. 96:1464-1468. 4 8 12 16 (inches) 30,000 plants/acre Wisconsin 30,000 plants/acre Wisconsin

30. Univ. of Kentucky, Grain Crops Extension © 2008 30 4 8 12 16 8 Mg/ha = 120 bu/acre Liua et al. 2004. Agron. J. 96:275-280 28,300 plants/acre Ontario 28,300 plants/acre Ontario inches

31. Liu et al., Crop Sci. 44:847-854 (2004). 4-inch deviation (doubles) 7-inch deviation (triples) 2-leaf delay4-leaf delay1-inch deviation 31 Univ. of Kentucky, Grain Crops Extension © 2008

32. Liu et al., Crop Sci. 44:847-854 (2004). 32 Univ. of Kentucky, Grain Crops Extension © 2008

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34. ECBSWCBBCWFAWCRW YieldGard CB ++ -+- YieldGard RW ----++ YieldGard Plus ++ -+ Herculex ++ - Herculex RW ----++ Herculex Xtra ++ Agrisure CB ++ -+- Agrisure RW ----++ Agrisure CB/RW ++ -+ R. Bessin, 2007 34 Univ. of Kentucky, Grain Crops Extension © 2008

35. WWWGFBSCMBCWCRW Gaucho++++ -- Prescribe ++ -+ Cruiser Ex Pak+++ +- Cruiser EP CRW ++ ++ Poncho 250+++ +- Poncho 1250 ++ R. Bessin, 2007 35 Univ. of Kentucky, Grain Crops Extension © 2008