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Delayed and Prevented Planting Sibley, 5-31-19
Joel DeJong
Field Agronomist
712-546-7835 (office)
712-540-1085 (cell)
@joel_dejong
Weather, 4/1 thru 5/29/19
Late Corn Planting Yield Expectations
Expected Yields with Delayed Planting
https://crops.extension.iastate.edu/cropnews/2019/05/late-corn-planting-options
Expected Yields with Delayed Planting
https://crops.extension.iastate.edu/cropnews/2019/05/late-corn-planting-options
Expected Yields with Delayed Planting
https://crops.extension.iastate.edu/cropnews/2019/05/late-corn-planting-options
Average first frost 1985 - 2015
Hybrid Maturity Considerationswith Late Planting
• Late planting have risk of
– killing frost before crop is physiological mature
– high grain moisture at harvest (↑ drying costs)
• $5 to $7 per acre/point cost of drying
• Recommendations for hybrid maturity:
– Until June 1: plant full season hybrids*
– After June 1: switch to an earlier relative maturity
Hybrids Adapt to Late Planting
• Require fewer Growing Degree Days (GDDs) to reach maturity with “late” planting
• After May 1, corn requires ~ 6.8 fewer GDDs/day to reach maturity (through at least 2nd week of June) (Nielsen et al., 2002)
GDDs – ( # days after May 1 x 6.8)
Example: Planting Date: June 1, 99-day hybrid
Rated 2376 GDDs (planting to physiological maturity)
2376 – (30 days x 6.8) = 2172 GDD to reach physiological maturity
Useful Resources
• Online Calculator to Adjust Hybrid GDD Requirement with to Late Planting: https://tinyurl.com/gddcalcu
• U2U – Growing Degree Day Tool: https://mrcc.illinois.edu/U2U/gdd/
• Late Corn Planting Options: https://crops.extension.iastate.edu/cropnews/2019/05/late-corn-planting-options
GDD Model, Osceola County, June 1 plant 99 day corn
I adjusted for “shortening” effect of late plant :
Take home messages
• Stay with well-adapted corn hybrids until June 1?
• Shorten corn maturities about 1 day for every two days after June 1
– Important to consider yield potential, disease resistance, and overall tolerance to stress
When do you quit planting corn?
But, looking forward…
Source: https://www.cpc.ncep.noaa.gov/products/predictions/long_range/seasonal.php?lead=1
https://farmdoc.illinois.edu/fast-tools/planting-decision-model
• Do any applied herbicides allow this?
• If it will be soybeans following soybeans, be sure to have an excellent disease package.
Is switching to soybeans an option?
• Photo sensitive
• Soybeans planted 40 – 60 days apart = 7 – 10 days later in maturing
• 0.5 – 1.0 MG spread = 3 – 5 days difference in maturing
Soybean adjustment to planting date
Soybean Yields and Planting Date
Average Planting Date
Northern Iowa Central Iowa Southern Iowa
% of maximum yield
Late April 100* 96* 98*
Early May 96* 100* 100*
Mid May 99* 96* 98*
Early June 81 93 89
Mid June 61 59 82
Early July 33 45 47
*Yields are statistically similar
NW Farm – Early June vs. Early May, 87% yield
N. Farm – Early June vs. Early May, 84% yield
Prevented Plant Considerations
• Weed Management
• Second crops: Forages
• Cover Crops: No grazing or haying until after Nov. 1
• Fallow syndrome
• Prevents “fallow syndrome”
• Protects the soil
– And holds phosphorus and potassium in place
• Takes up nitrogen
• Builds organic matter
• NO grazing or haying until after Nov. 1
Cover crops with prevented planting
• Soybean @ 60-80 K./Ac. In 15 or less inch rows
– Advantages
• Inexpensive
• Works well if soybean herbicides have been applied
• May be hayed or grazed on November 1 and later
• Winter kills
– Disadvantages
• Limited cover and nitrogen scavenging in the spring
• Very sensitive to many corn herbicides
• No harvesting for grain
Potential cover crops – short list
• Corn @ 60-80 K./ Ac.
– Advantages
• Inexpensive
• Works well if corn herbicides have already been applied
• May be hayed or grazed on November 1 and later
• Winter kills
– Disadvantages
• Less canopy than soybean
• Likely some seed production– Volunteer in 2020
• Likely need to be mowed down in the fall
• No harvesting for grain
Potential cover crops – short list
• Oats @ 1 – 1.5 bu./Ac.
– Advantages
• Inexpensive
• Late spring / early summer planting will mature and shatter
– Some seeds will germinate in the fall
• May be hayed or grazed on November 1 and later
• Winter kills
– Disadvantages
• Limited cover and nitrogen scavenging in the spring
• Very sensitive to many herbicides
• Poor spread pattern from an aerial application
– Consider spring barley
• Some shattered seeds will volunteer in the spring
Potential cover crops – short list
• Cereal rye @ 1 – 1.5 bu./Ac.
– Advantages
• Fairly inexpensive
• Most forgiving of herbicides already applied
• Protects the soil and scavenges nitrogen both Fall and Spring
• May be hayed / grazed on November 1 or later and in the spring
• Clipped cereal rye over winters very well
– Disadvantages
• Unclipped early-planted cereal rye has noticeable winterkill
• Must be terminated in the spring
• May interfere with early corn planting
Potential cover crops – short list
• What are you wanting?
Second Crop: Potential forage options
Dry Hay Options Silage Options Grazing Options
Oats Oats Oats
Foxtail Millet Foxtail Millet Foxtail Millet
Japanese Millet Japanese Millet Japanese Millet
Sudangrass (maybe) Sudangrass Sudangrass
Sorghum X Sudan Hybrid Sorghum X Sudan Hybrid
Hybrid Pearl Millet Hybrid Pearl Millet
Short Grain Sorghum/Forage Soybean Mixture
Short Grain Sorghum/Forage Soybean Mixture
Be cautious of…
• Prussic acid poisoning caused by frosted or grazed
– Sudangrass
– Sorghum-sudangrass hybrids
– Forage sorghum
– Grain sorghum
• High nitrates if the summer turns dry
• Forage and Cover Crop Considerations for Delayed Planting and Flooded Sites:
• https://crops.extension.iastate.edu/cropnews/2008/06/forage-and-cover-crop-considerations-delayed-planting-and-flooded-sites
• Prevented Planting and Cover Crop Considerations: https://crops.extension.iastate.edu/cropnews/2013/06/prevented-planting-and-crop-cover-considerations
Useful Resources