Poultry litter offers source of nutrients for soybeans
Feb. 15, 2006Contact Information:
Dr. Nathan Slaton, Department of Crop, Soil and Environmental Sciences
479-575-3910 / nslaton@uark.edu
By Fred Miller, University of Arkansas Division of Agriculture
479-575-5647 / mailto:fmiller@uark.edu\
Research technologist Betsy Murdoch uses a spectrographic instrument to analyze the phosphorus and potassium content of soybean tissue samples from plants grown in test plots fertilized with poultry litter.
FAYETTEVILLE, Ark. — University of Arkansas Division of Agriculture research demonstrates that poultry litter is a viable source of phosphorus and potassium fertilizer for soybeans.
“Use of litter as a nutrient source for soybeans is different from other crops like rice,” said Dr. Nathan Slaton, director of the Arkansas soil testing and research program.
Nitrogen is a key element in fertility studies for other crops. But soybeans are legumes, plants that fix their own nitrogen from the air through a symbiotic relationship with bacteria in the soil. “They’re like little nitrogen factories,” Slaton said.
Slaton and Dr. Chris Tingle, Extension soybean agronomist, applied poultry litter to soybean test plots at different rates based on phosphorus content. Potassium content was also calculated at those rates. The results were compared to inorganic phosphorus and potassium sources applied at the same nutrient rates.
Research at other universities suggests that applying litter on soybeans is a feasible option for disposing of it. But Slaton and Tingle are trying to determine if poultry litter is a suitable substitute for inorganic fertilizers.
“What we’ve seen is that there is little or no difference in plant performance between the litter and commercial fertilizer at the same rates,” Tingle said. “Our tests, so far, show poultry litter is a viable source for phosphorus and potassium.”
Slaton said there can be variation in nitrogen, phosphorus and potassium contents in different loads of poultry litter depending on several factors, including how many flocks were raised before it was cleaned out.
“We recommend sending samples of poultry litter to the Division of Agriculture diagnostic lab in Fayetteville for analysis of nutrient content,” he said.
Slaton said the nitrogen content in poultry litter should not be problematic for soybeans and may even be beneficial in some cases.
“The nitrogen in poultry litter tends to boost early season soybean growth,” he said. “When the nitrogen from the poultry litter is gone the nitrogen-producing mechanism in soybean kicks in.”
“The first 30 to 40 days are critical in establishing the relationship between the plant and the bacteria that work to fix the nitrogen,” Tingle said. “We want to be careful that we don’t disrupt that and end up with a nitrogen deficiency.”
“We feel like poultry litter can be used in soybeans,” Tingle said. “Our research will develop recommendations based on phosphorus that growers can count on if they choose to use it as an alternative to inorganic fertilizers.”