Farm Progress is part of the Informa Markets Division of Informa PLC

This site is operated by a business or businesses owned by Informa PLC and all copyright resides with them. Informa PLC's registered office is 5 Howick Place, London SW1P 1WG. Registered in England and Wales. Number 8860726.

Serving: IA

Don't apply manure too early

TAGS: Fertilizer
Farm Progress Manure being applied to soil
AVOID N LOSS: It’s best to wait until soils cool down to at least 50 degrees F and stay there before applying manure in the fall.
Applying manure too early in fall can lead to corn yield loss.

The early harvest this year in Iowa has created opportunities to complete fall fieldwork and manure applications much earlier than usual. However, applying manure before soils have cooled to below 50°F can be a costly decision.

“Pushing manure application to later in the fall or waiting until spring can help to prevent nitrogen loss and better match nutrient availability with nutrient demand by crops,” says Brian Dougherty, an Iowa State University Extension ag engineer in northeast Iowa.

A research trial at the ISU Northeast Research and Demonstration Farm near Nashua found significant yield reductions when fall manure was applied when soil temperatures exceeded 50 degrees. In a corn-soybean rotation, late-fall-applied manure (soils less than 50 degrees) averaged 40 bushels per acre greater corn yield than early fall manure over a three-year period from 2016 to 2018.

Weather conditions in the fall 2018 prevented the early-to-late fall manure comparison for 2019. However, in a late-fall-to-spring comparison, the spring manure treatment had an 18 bushel-per-acre yield advantage.

Research: Better to wait

Similarly, a late-fall-to-spring comparison in continuous corn showed a 38-bushel-per-acre yield advantage (three-year average) for the spring-applied manure. Research conducted at other locations has also reported yield advantages with delaying manure application timing, as shown in the table below.

Corn yield and gross revenue with delayed manure application table

“There is always a possibility of poor weather conditions if manure application is delayed,” Dougherty says, “but this needs to be compared with the risk of nitrogen loss and lower yields when manure is applied too early in the fall.”

He suggests reading an article on the ISU post Improving crop yields and water quality with manure management for more information, including the effects of a cereal rye cover crop with early-fall applied manure.

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 contained in this information asset.


Hide comments


  • Allowed HTML tags: <em> <strong> <blockquote> <br> <p>

Plain text

  • No HTML tags allowed.
  • Web page addresses and e-mail addresses turn into links automatically.
  • Lines and paragraphs break automatically.