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Published May 19, 2014, 09:31 AM

NDSU study shows manure has crop production role

Though it’s too late for most crops this growing season, Mary Berg has an old-school solution for coming years: The use of animal manure to fertilize fields.

By: Jonathan Knutson, Agweek

Many Upper Midwest farmers wonder whether they’ll have access to enough commercial fertilizer this spring.

Though it’s too late for most crops this growing season, Mary Berg has an old-school solution for coming years: The use of animal manure to fertilize fields.

“It’s something crop producers should check into,” says Berg, livestock environmental management area specialist with the North Dakota State University Extension Service research center in Carrington.

Berg was part of a multi-year study at the research center that looked at using animal manure in crop production. Manure has many nutrients, including nitrogen, phosphorus and potassium, but it must be managed differently than commercial fertilizer. As a result, many crop producers are reluctant to fertilize with manure, according to the study.

The study looked at using manure to fertilize corn, canola and spring wheat, three commonly grown crops in the state.

Among the study’s findings:

• Corn yields didn’t vary significantly when commercial fertilizer versus spring-applied manure were compared.

• Canola yields were significantly lower with spring-applied manure than commercial fertilizer. The release of nitrogen from spring-applied manure was found to be too slow for the high demands of canola.

• For spring wheat, the results of fall-applied manure and commercial fertilizer were statistically similar.

Anyone interested in using manure as a crop fertilizer should take a sample to test its nutrient content, Berg says.

The nutrient content depends on a number of factors, such as the type of livestock, an individual animal’s age and what it’s been fed, she says.

Working together

Historically, many ag producers in the Upper Midwest have raised both crops and livestock. That makes it relatively easy for a producer who raises both to take manure from his livestock and apply it to his fields.

“If producers have livestock on their place and also have fields, it’s just a way to recycle their nutrients,” Berg says.

In recent years, however, a growing number of producers are getting out of livestock to focus only on crops, in part because of strong crop prices.

Berg says that specialization means “we, as two separate industries, need each other now more than ever. We can really use those specializations to help both industries prosper.”

Using manure as a crop fertilizer might seem old-fashioned to some. But Berg says she’s heard farmers engaged in precision agriculture talk about using manure in their precision ag system to give crops “an extra little boost.”

Precision ag involves fine-tuning the amount of inputs, such as seed and fertilizer, applied to every square foot of a field.

“If you’re a crop producer, make friends with your cattle neighbors,” she recommends. “If you’re a crop producer driving down the road and you see a cow, stop in.”

In North Dakota, a farmer receiving animal manure usually pays the transportation cost.

In some states, a farmer who receives manure pays the transportation cost and an additional fee, she says.

For more information on the Carrington research center’s manure study visit www.ag.ndsu.edu/pubs/h2o qual/wat nut/nm1629.pdf.

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