Experiments using poultry litter for fertilizer began 11 years ago at the Riesel Watershed Center. Poultry litter, an often pungent combination of bedding material and manure, is sometimes more popular with the farmers and ranchers who use it than it is with their neighbors.
Daren Harmel, an agriculture engineer for the Agriculture Research Service, and others involved with the research, were on hand at the Riesel center last month to share with producers from Falls, Limestone and McLennan Counties what they have learned about poultry litter as fertilizer and what else they hope to learn as the studies continues. Harmel said the first decade of research has shown that poultry litter can be a great fertilizer for both crops and hay, but it has to be managed properly, from the onsite facilities where it is collected to the fields where it is applied.
Once it is applied, it may emit a distinctive odor that may not bother a producer as much as it bothers neighbors. "The neighbors may not like the smell as much as you do," he said.
Craig Coufal, an assistant professor and Extension specialist, has been studying a practice known as In-house Windrow Composting, which collects the manure from large poultry houses in conical rows -- windrows -- that run the length of the poultry house and are piled two- to three-feet high. The mixing, piling and turning processes allows non-pathogenic bacteria in the litter to grow and proliferate, which work to basically pasteurize the litter, similar to the way manure is composted. Coufal calls it an "abbreviated composting process.
"The process only goes eight or nine days," he said. "It's not really true composting. It's more like pasteurization."
Recently, researchers had volunteers sit at the edge of a couple of big fields at the center where untreated litter was applied to one field and windrowed litter applied to another. The volunteers were asked to simply report if they smelled anything.
"The windrowed compost has a different odor, maybe a little less pungent and less offensive," Coufal said.
The main purpose of windrow composting is not to make it smell better, but to kill the pathogens, which studies have shown it does. The pathogens that do survive die in the field. The nutrient content of windrowed litter as opposed to untreated is about the same, he said.
The process has to start in the poultry houses, and Coufal said that most of the big poultry houses in the state have at least tried the process; some have stuck with it and others have not. The research started about the same time that a large processing house in Waco opened. Harmel said the idea was to see if farmers could use the manure from poultry houses the same way that large dairies in the area have been able to sell their waste as compost.
"We wanted to get ahead of that," he said.
Eleven years later, they have learned some good lessons for producers who want to try it on their own fields and pastures. About two tons of litter per acre is recommended for fields, three tons per acre for pastures, with some supplemental nitrogen added, if needed.
Agriculture scientist Rick Haney told producers about the soil test he devised at the Blackland Research Center in Temple that tests soil more from a biological standpoint than chemical and delivers information on how much nitrogen, phosphorus and potassium, in pounds per acre, is already available to the plant.
"It's like free fertilizer," Haney said. "It accounts for the nutrients that nature gives us for free."
The cost of poultry litter has gone up from $16.50 a ton when the study started to $33 a ton now. Nitrogen was $125 a ton in 2000, and peaked at $655 a ton in 2007, and sells for $545 a ton now.
"The cost has gone up, but not as much as commercial nitrogen," Harmel said.
Coufal pointed out that Texas is the sixth leading poultry producer in the nation and he believes there is an opportunity for the industry to grow in the state. If it works out that way, farmers and ranchers may end up with another fertilizer option.
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