Study: Pig manure as effective as other fertilizers

OTTAWA, Ohio – Applying livestock manure to growing crops has been found to produce yields comparable to traditional fertilizer applications, and the alternative option may mean more money in a farmer’s pocket.
Glen Arnold, an Ohio State University Extension educator in Putnam County, along with the Putnam County Soil and Water Conservation District, has been working with area farmers for the past two years to determine how well swine manure applications to corn and wheat in the spring compare to traditional applications of nitrogen and urea.
Comparable. What the group found was that corn and wheat yields applied with manure yielded just as well, if not a few bushels more, compared to crops treated with traditional fertilizers.
For farmers, like Dennis Niese, that may mean as high as a $40-per-acre savings in fertilizer inputs.
The Leipsic, Ohio, hog producer, who also grows corn, soybeans and wheat, got on board with the Ohio State project last year to use liquid manure from his finishing facilities to top-dress wheat in the early spring.
The wheat top dressed with manure out-yielded the wheat top dressed with urea by about eight bushels per acre.
The group plans to replicate the experiment again next year.
Inexpensive option. “The results indicate that livestock manure is an excellent source of nitrogen for growing crops,” said Arnold.
“The importance is not so much the yields as it is the alternative, inexpensive option farmers have for applying fertilizer, especially in no-till situations.”
Albert Maag of the Putnam County Soil and Water District said that research shows farmers are willing to embrace new technology and improve their management practices because of it.
“People look upon manure as a waste product, but we wanted to see how farmers could benefit from it, and improve the management of their crops by effectively utilizing high-risk nutrients,” said Maag.
Methodology. The swine manure was applied as a one-time application to wheat in the early spring, rather than the fall for several reasons, said Arnold.
“One is that the application to a growing crop can add an additional window of time rarely utilized for manure application,” said Arnold.
“Also, you generally lose ammonium nitrogen when fertilizer is applied in the fall.
“Applying animal manure to a growing crop in the spring allows the crop to capture more of the manure’s nutrients and use the nutrients right when it is most needed.”
In addition to phosphorus, potassium and a host of micronutrients, livestock manure contains organic nitrogen and ammonium nitrogen.
More than half the nitrogen in liquid livestock manure is typically ammonium nitrogen. The ammonium nitrogen and approximately one third of the organic nitrogen in livestock manure is available to growing crops during the season of application.
Application. To ensure Niese’s wheat crop used the most of swine manure, the material was applied using a terra-gator, equipment that cuts a narrow slot at 7.5-inch spacings and places the manure into the cuttings.
The process is environmentally friendly because it reduces odor and decreases chances for run-off.
Niese admits that the application process made him a bit nervous.
“You are invariably cutting into some of the wheat crop to get the manure application as close to the crop as possible. You basically have one chance per year to make money. Any damage to the crop puts you at risk,” said Niese.
The application process, however, did not seriously damage the wheat crop, nor did it decrease yields, emphasized Arnold.
Disadvantages. Like any new management practice, disadvantages come with advantages.
One drawback is making sure enough facilities are available to store manure until it is ready for application.
Generally, over 3,200 gallons of liquid manure is required per acre to meet a plant’s nutrient requirements, compared to about 100 units of nitrogen in the form of urea.
Producers should also be careful when applying manure to frozen ground, which could be a factor in early spring.
It is recommended producers follow Natural Resources Conservation Service guidelines (Practice Standard 633) if manure application on frozen or snow-covered ground becomes necessary.
Equipment costs. Perhaps the most limiting factor for farmers is the cost of the equipment to apply the manure, which can set a farmer back by as much as a quarter of a million dollars.
“If farmers have access to this or similar equipment, then this management practice is a way of using what is already present on a farm, rather than buying the inputs,” said Arnold.