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Delayed and Prevented Planting Sibley, 5-31-19

Joel DeJong

Field Agronomist

jldejong@iastate.edu

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