Wallaces Farmer

Farmers with cornfields destroyed by the derecho windstorm face fall management decisions.

August 28, 2020

3 Min Read
Badly damaged cornfields from wind
FLATTENED FIELDS: Some cornfields and parts of fields are so badly damaged from wind that they can’t be harvested for grain. Rod Swoboda

Millions of corn acres have been damaged by the derecho windstorm on Aug. 10 that swept across a wide area of central and eastern Iowa. Unfortunately, for some of these acres, harvest will not take place. Decisions regarding fall management options will need to be made in the coming weeks. 

To help farmers with those decisions, Iowa State University Extension agronomists Josh Michel and Mark Licht provide the following information. They say you need to focus on these key considerations:  

Disking, vertical tillage, stalk shredding. Disking or using vertical tillage or stalk shredding will reduce the size of residue, speed up decomposition and encourage some corn grain to germinate this fall. Greater germination this fall means less volunteer corn in the spring. If choosing to disk the field, minimal soil disturbance is recommended to avoid potential erosion, prevent soil structure degradation and assist with better water infiltration.  

Maintaining crop residue cover on the soil surface will reduce erosion and help maintain soil moisture reserves by reducing water evaporation from the soil. Looking ahead to planting next spring, soybeans can be forgiving when planted into high amounts of corn residue. 

Volunteer corn. High populations of volunteer corn may emerge next spring even after disking, using vertical tillage or stalk-shredding this fall. It can be relatively easy to manage volunteer corn in a soybean field. However, a late flush of volunteer corn may emerge if the soybeans are preceded with a cereal rye cover crop. Be aware of what corn herbicide traits were used this year and what traits will be used in 2021 during planting, and make any needed adjustments to your herbicide program.  

It is recommended to avoid planting corn following corn in 2021 if severe damage has occurred in the field. That’s because the volunteer corn will be difficult to manage since it is also selective to corn herbicides. Additional information can be found at Control of Volunteer Corn in Soybean and Corn

Nutrient value of damaged corn. It’s helpful to understand the fertilizer nutrient value of wind-damaged corn, since so many cornfields and parts of fields have been flattened by the wind and will not likely be harvested for grain. 

When corn plants are broken off and die, and not removed or grazed, certain amounts of phosphorus  and potassium remaining in the field will be available for next year’s crop. The content value of P and K varies by what reproductive stage the corn was in, its productivity or yield level, and the growing conditions throughout the year.  

Nitrogen remaining in nonharvested corn plants will cycle through the soil system. When planted into soybeans the following year, changes in N cycling won’t affect the soybean crop. If the field is planted back into corn the following year, there is the potential for higher-than-normal amounts of mineralized N to be available. However, this takes into account rainfall amounts and other factors that may influence N mineralization from late summer until next spring. Additional information can be found in the article Wind Damaged Corn — Nutrient Content? 

Cover crops. Planting cover crops is still an option. However, your success in planting cover crops this fall in fields that are not harvested will greatly depend on increasing the seed-to-soil contact and reducing the size of the corn crop residue. Both of these steps can be accomplished through disking, vertical tillage or stalk shredding.  

Seeding with a drill may also be considered for planting the cover crop. No matter which planting method is chosen, seeding should be delayed until rain is in the forecast. Cereal rye is the most popular cover crop species and should be used because of its overwintering benefits. 

Source: ISU, which is solely responsible for the information provided and is wholly owned by the source. Informa Business Media and all its subsidiaries are not responsible for any of the content in this information asset. 

 

 

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