Chad LeeGrain Crops Extension

859-257-3203cdlee2@uky.edu

1Univ. of Kentucky, Grain Crops Extension © 2008

Soil temperature Soil moisture Seeding depth Seed spacing

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2008

Planting too early or too late can reduce yields

Univ. of Kentucky, Grain Crops Extension © 2008 3

Univ. of Kentucky, Grain Crops Extension © 2008

50 OF at a 2-inch depth for three or four days is excellent.

Soil temperature at 50 OF at 7:00 am or 55 OF at 1:00 pm

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Univ. of Kentucky, Grain Crops Extension © 2008 5

Town Coordinances Date of Last Spring Occurrence of 32° Fa,b

(°) Median Early 10% 90% LateOwensboro 37.77N 87.11W 4/10 3/21 3/25 4/24 5/05Paducah 37.08N 88.62W 4/08 3/07 3/22 4/18 4/23

Lexington 38.03N 84.44W 4/18 3/26 4/04 5/03 5/10Princeton 37.09N 87.89W 4/10 3/21 3/26 4/21 3/26

Univ. of Kentucky, Grain Crops Extension © 2008

Planting Date: •April 1 – May 1 (central and western KY)•April 15 – May 15 (eastern KY)

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Average

Planting

Date

Corn Yield (Bu/Acre)*

(6 -Yr Avg.)

(2000 - 2005)

Avg.

Loss

(Bu/A)

April 7 196 -14

April 22 210 0

May 9 193 -17

May 24 172 -38

June 9 130 -80

*Average of 2 hybrids (Bt & Non-Bt)

Univ. of Kentucky, Grain Crops Extension © 2008 7

J. Herbek and R. Bessin

Average Planting

Date

Corn Yield (Bu/A)

(2000-2005) Bt Hybrid Advantage

(Bu/A)Non-Bt Hybrid Bt Hybrid

April 7 195 197 +2

April 22 208 211 +3

May 9 189 196 +7

May 24 167 178 +11

June 9 118 141 +23Univ. of Kentucky, Grain Crops Extension © 2008 8

Herbek and Bessin

Average

Planting

Date

Corn Yield (Bu/Acre)*

(6 -Yr Avg.)

(2000 - 2005)

Avg.

Loss

(Bu/A)

April 7 196 -14

April 22 210 0

May 9 193 -17

May 24 172 -38

June 9 130 -80

*Average of 2 hybrids (Bt & Non-Bt)

Univ. of Kentucky, Grain Crops Extension © 2008 9

J. Herbek and R. Bessin

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

Princeton Lexington

May 1 - 7

April 19 - 25

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2008

Princeton Lexington Owensboro?

May 1 - 7

April 19 - 25

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Univ. of Kentucky, Grain Crops Extension © 2008 13

Planting Henderson PrincetonDate Aug 31 Aug 31

GDD GDDMar. 1, 2007 3531 3816Apr. 5, 2007 3188 3364Apr. 20, 2007 3132 3255

About 2700 to 3000 GDD’s needed for blacklayer.

Town Coordinances Date of Last Spring Occurrence of 32° Fa,b

(°) Median Early 10% 90% LateOwensboro 37.77N 87.11W 4/10 3/21 3/25 4/24 5/05Paducah 37.08N 88.62W 4/08 3/07 3/22 4/18 4/23

Lexington 38.03N 84.44W 4/18 3/26 4/04 5/03 5/10Princeton 37.09N 87.89W 4/10 3/21 3/26 4/21 5/26

Univ. of Kentucky, Grain Crops Extension © 2008 14

    Hybrid Maturity (GDD)Planting 2400 2700 3000

Kentucky Location Date Date to Reach Black LayerMayfield 3/15 7/28 8/8 8/20

4/1 8/1 8/13 8/244/15 8/6 8/18 8/30

5/1 8/14 8/26 9/85/15 8/23 9/4 9/19

6/1 9/5 9/20 10/11

Bowling Green 3/15 7/27 8/7 8/194/1 7/31 8/12 8/23

4/15 8/5 8/17 8/295/1 8/12 8/24 9/5

5/15 8/21 9/2 9/166/1 9/3 9/18 10/7

Henderson 3/15 7/27 8/8 8/204/1 8/1 8/13 8/24

4/15 8/6 8/18 8/305/1 8/14 8/25 9/7

5/15 8/23 9/4 9/196/1 9/5 9/20 10/9

Planting Date

1 WAP 2 WAP 3 WAP 4 WAP

Mar 1, 2007 21 85 115 239

Mar 14, 2007

44 168 271

Apr 1, 2007 15 66 130 247

Apr 15, 2007

64 180 312

Apr 20, 2007

12 129 260

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).

Univ. of Kentucky, Grain Crops Extension © 2008 16

Town Coordinances Date of Last Spring Occurrence of 32° Fa,b

(°) Median Early 10% 90% LateOwensboro 37.77N 87.11W 4/10 3/21 3/25 4/24 5/05Paducah 37.08N 88.62W 4/08 3/07 3/22 4/18 4/23

Lexington 38.03N 84.44W 4/18 3/26 4/04 5/03 5/10Princeton 37.09N 87.89W 4/10 3/21 3/26 4/21 5/26

Univ. of Kentucky, Grain Crops Extension © 2008

1 ½ to 2 inches (into moisture)

Tips to Reduce Planter Performance Effects on Corn YieldAGF-150-01Greg La BargeExtension Agent, Ohio State University Extension Dr. Peter ThomisonExtension Specialist, Corn Production http://ohioline.osu.edu/agf-fact/0150.html

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Low areas

High Areas

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

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

Univ. of Kentucky, Grain Crops Extension © 2008 25

y = -0.2244x + 2.0377

r2 = 0.92

1.4

1.45

1.5

1.55

1.6

1.65

1.7

1.75

1.8

1.85

1 1.2 1.4 1.6 1.8 2 2.2 2.4 2.6

Organic matter (%)

Max

imu

m B

ulk

Den

sity

(g

/cc)

y = -0.2244x + 2.0377

r2 = 0.92

1.4

1.45

1.5

1.55

1.6

1.65

1.7

1.75

1.8

1.85

1 1.2 1.4 1.6 1.8 2 2.2 2.4 2.6

Organic matter (%)

Max

imu

m B

ulk

Den

sity

(g

/cc)

Organic Matter and Soil Compaction

G. Schwab

Spacing Between

Rows(inches)

Plant Population(plants/acre)

Spacing Within Rows

(inches)

30 30,000 7.0

30 24,000 8.7

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

Spacing Between

Rows(inches)

Plant Population(plants/acre)

Spacing Within Rows

(inches)

Allowable Within Row

Spacing

(inches)

30 30,000 7.0 5.0 - 9.0

30 24,000 8.7 6.7 - 10.7

Univ. of Kentucky, Grain Crops Extension © 200827

Variability up to 2 inches does not hurt yields. Variability above 2 inches will reduce yields.

R.L. Nielsen

Elora

0

2

4

6

CT-V CT-F NT-V NT-F

SD

(inc

hes)

Mean

0

2

4

6

CT-V CT-F NT-V NT-F

SD

(inc

hes)

Woodtsock

0

2

4

6

CT-V CT-F NT-V NT-F

SD

(inc

hes)

Univ. of Kentucky, Grain Crops Extension © 200828

4.5 mph

7.0 mph

3 locations in Ontario, Canada2 years28,900 seeds/acre* Sig. Difference between speeds

Tollenaar et al. 2004. Agron. J. 96:1668-1672

* **

**

***

*

Univ. of Kentucky, Grain Crops Extension © 200829

Lauer and Rankin. 2004. Agron. J. 96:1464-1468.

4 8 12 16

(inches)30,000 plants/acreWisconsin

30,000 plants/acreWisconsin

Univ. of Kentucky, Grain Crops Extension © 200830

4 8 12 16

8 Mg/ha = 120 bu/acre

Liua et al. 2004. Agron. J. 96:275-280

28,300 plants/acreOntario

28,300 plants/acreOntario inches

Liu et al., Crop Sci. 44:847-854 (2004).

4-inch deviation (doubles)

7-inch deviation (triples)

2-leaf delay 4-leaf delay1-inch deviation

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Liu et al., Crop Sci. 44:847-854 (2004).

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ECB SWCB BCW FAW CRW

YieldGard CB ++ ++ - + -

YieldGard RW - - - - ++

YieldGard Plus ++ ++ - + ++

Herculex ++ ++ ++ ++ -

Herculex RW - - - - ++

Herculex Xtra ++ ++ ++ ++ ++

Agrisure CB ++ ++ - + -

Agrisure RW - - - - ++

Agrisure CB/RW ++ ++ - + ++

R. Bessin, 200734

Univ. of Kentucky, Grain Crops Extension © 2008

WW WG FB SCM BCW

CRW

Gaucho ++ ++ + ++ - -Prescribe ++ ++ ++ ++ - +Cruiser Ex Pak ++ ++ ++ ++ + -Cruiser EP CRW

++ ++ ++ ++ + ++

Poncho 250 ++ ++ ++ ++ + -Poncho 1250 ++ ++ ++ ++ ++ ++

R. Bessin, 2007

35Univ. of Kentucky, Grain Crops Extension ©

2008