Published March 27, 2008 11:22 am -
Optimizing fertilizer value of manure
University of Missouri
Using poultry litter and other animal manures can help lessen the pinch of high fertilizer prices according to Jay Chism, agronomy specialist with University of Missouri Extension.
“Livestock producers are having a hard time justifying the high cost of commercial fertilizer. If available, animal manures may be a good option,” said Chism.
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.
Not Readily Available
“Nutrients in animal manures are not as readily available,” said 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.
“The best way to determine fertilizer value of litter is to have it tested,” said Chism. “A nutrient analysis will provide a good understanding of how much litter needs to be applied to get maximum plant growth.
As a general rule, poultry litter will have around 40 lbs. of N, 75 lbs. of P2O5 and 45 lbs. of K2O, according to Chism.
“Many times hauling charges will add to the cost of adding litter to pastures and hay fields,” said Chism.
Another 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.
Cost Effective