Manure application

For farmers who apply manure in the spring, the window of opportunity will be arriving soon. 

With much of the Midwest going from a thick layer of snow to flooding, thoughts of spring field work seem like a dream.

But it is time to think about fertilizing pastures and crop ground.

For farmers who apply manure in the spring, the window of opportunity will be arriving soon, says Rebecca Vittetoe, Extension agronomist with Iowa State University based in Washington, Iowa.

“The weather is obviously going to play a role when you can apply manure,” she says. “We have a lot of snow that has to melt.”

Iowa law prohibits applying manure on snow through April 1. Manure may be applied to frozen ground from Feb. 1 to April 1.

Once the snow is gone, Vittetoe says the weather forecast should be checked ahead of application. If rain is in the forecast within 48 hours, it is best to wait so that nutrients stay in the ground.

The nutrients in liquid manure will be more readily available than those in dry manure.

Vittetoe says the earlier manure can be applied, the better it can be utilized by both crop and pasture ground.

“Most apply in the fall so they have a larger window to utilize the nutrients,” she says. “There were some challenges applying manure last fall, however, because of the rain.”

Ground temps below 50 degrees

Yields are usually better when manure is applied in the spring, Vittetoe adds, but soil temperatures need to reach 50 degrees or higher for ideal nutrient utilization.

“Logistically speaking, it might just be better to do it in the fall,” she says.

Pastures can receive a huge boost from a spring manure application, says Bruce Anderson, Extension agronomist with the University of Nebraska. He says before manure is applied, soil fertility must be assessed and any manure should be sampled for nutrient levels.

“You want to apply as soon as you can do it physically and legally,” Anderson says.

Fields with known nutrient deficiencies should be targeted. He says most producers will know which pastures likely need a nutrient boost.

Anderson says alfalfa fields should be fertilized fairly close to seeding.

“I would like to see some rain fall between application and seeding,” he says. “The alfalfa will not see much benefit from the nitrogen, but you will see some benefit from the phosphorus and potassium.”

Jeff DeYoung is livestock editor for Iowa Farmer Today, Missouri Farmer Today and Illinois Farmer Today.