Using poultry litter and other animal manures can help lessen the pinch of high fertilizer prices,” said Jay Chism, Agronomy Specialist with University of Missouri Extension in Barton County. “Livestock producers are having a hard time justifying the high cost of commercial fertilizer. If available, animal manures may be a good option."
When comparing fertilizers to manures, producers need to remember most commercial fertilizers are 100 percent available when applied to the soil. Fertilizers such as ammonium nitrate, urea and ammonium sulfate are in a form that is available to forages or convert readily for plant uptake. Likewise phosphorus is very soluble in fertilizers. Commercial fertilizers are highly concentrated and can provide a guaranteed analysis uniformly to a pasture.
“Nutrients in animal manures are not as readily available,” adds Chism. Manures contain both organic nitrogen and mineral forms of nitrogen. Plants cannot directly use organic nitrogen. Soil microbes must first break down the organic nitrogen to a mineral form the plants can use. Phosphorus is also in an organic form that is not readily available. Manures are generally in low concentrations and may have variable fertilizer value.
Nutrient Analysis
“The best way to determine fertilizer value of litter is to have it tested,” said Chism. (Visit www.extension.missouri.edu and search for G9340.) “A nutrient analysis will provide a good understanding how much litter needs to be applied to get maximum plant growth,” added Chism. “As a general rule, poultry litter will have around 40 lbs of N, 75 lbs of P2O5 and 45 lbs of K2O,” said Chism. “Many times hauling charges will add to the cost of adding litter to pastures and hay fields." Other potential value to litter is the addition of extra nutrients. Poultry litter will provide sulfur, magnesium, calcium, and zinc. In some cases, a liming affect can also be attributed to the addition of manure.
Poultry litter can be a cost effective fertilizer for fescue fields. An application in mid August fits well in to many cool season grass/legume pastures. The fall timing will provide the nutrient requirements for fall growth and extended grazing. Applications at this time have less potential for runoff than spring applied litter when early season rainfall occurs.
Ideal forage management in Missouri includes maintaining legumes in fescue stands. “High rates of nitrogen fertilizer, whether commercial fertilizer or manure can be detrimental to legumes like clover and lespedeza,” said Chism. Fall applied manure limits the negative effects of manure on fescue/clover pasture stands. “Many times the additional phosphorus in the manure will allow legumes to persist longer in fescue pastures. Available crop nutrients in the soil need to be determined in order to really make good decisions about purchasing commercial fertilizer or animal manure. If you don’t need the nutrients, there is no reason to purchase the fertilizer,” Chism added.
