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Achieving maximum profit

A study by researchers at the U.S. Department of Agriculture’s Agricultural Research Service is determining limits to chicken litter as fertilizer.


November 16, 2016
By researchers at the USDA’s Agricultural Research Servic

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Applying raw broiler litter on a no-till cotton field just before planting cotton using a small mechanical spreader. Photo by H. Tewolde

 

Each year, more than 14 million tons of chicken litter is generated in the U.S. Studies have shown that using poultry litter to fertilize crops can be as effective as using synthetic fertilizers.

In a new study, researchers at the USDA’s Agricultural Research Service have calculated how much chicken litter farmers need to apply to cotton crops to maximize profits.

“Most research focuses on the amount of poultry litter needed to maximize crop yields,” says Haile Tewolde, lead author of the study. “We wanted to know if aiming for maximum yield always makes economic sense for farmers.”

Tewolde and his colleagues found that it doesn’t. Using less chicken litter than what was needed to maximize crop yields actually increased profits for farmers. Profits increased even though crop yields were lower.

It might appear that higher crop yields would lead to higher profits. But using more fertilizer also increases costs for farmers. The researchers predicted that once an optimal amount of fertilizer had been applied to crops, any more would raise costs more than profits.

The study was conducted in two farms in Mississippi. Researchers applied varying amounts of chicken litter as fertilizer on replicated plots then compared yield and profitability. They also compared the use of synthetic fertilizers and chicken litter.

They found that chicken litter applications over a certain level did not result in net economic gains. Instead, it led to economic losses even though yields were somewhat higher.

Maximum cotton yields were achieved by applying between 9,000 to 12,000 pounds of chicken litter per acre. In contrast, applying about 7,000 pounds of chicken litter per acre each year was enough to maximize profits.

The researchers also confirmed studies that showed chicken litter to be as effective – sometimes more so – than synthetic fertilizers.

If farmers can use less poultry litter and still maximize profits, pollution can be managed more effectively.