Potential for forest biochar and poultry waste use as fertilizer

In rural Arkansas, a cooperative experiment is underway by scientists from the University of Arkansas at Monticello College of Forestry, Agriculture, and Natural Resources in collaboration with the University of Arkansas System Division of Agriculture Drew County Extension Service. 

Their mission is to explore the potential of biochar, a product of heating timber waste at high temperatures without oxygen, as a fertilizer in forage production. The goal is to determine if combining biochar with poultry litter can significantly boost hay growth. 

The implications are significant. A positive outcome could provide the forest industry with a new eco-friendly byproduct for wood mill residues and provide farmers in southeast Arkansas with a cheaper option for synthetic fertilizers. While chicken litter is a valuable source of fertilizer that has been utilized for decades, it has become harder to acquire, and transportation and application of it have become more expensive.

Neither University of Arkansas at Monticello Assistant Professor of Agronomy Kathleen Bridges nor Drew County Extension Agent Scott Hayes know what to expect. “We don’t know if it will be good or bad. It could be a negative thing, but hopefully science will reveal that,” said Bridges. Bridges specializes in soils and crop sciences. Hayes said, “This research is somewhat new. Most of our producers in this area use chicken litter as a fertilizer for their hay pastures. By mixing this with the biochar, we hope to see better soil health through microbial activity.” 

Hayes and Bridges launched their project in June with twenty 3×3 meter plots in a hayfield across from the UAM Agriculture Building. A local Monticello company donated the biochar, and Hayes had a friend who supplied the chicken waste. They mixed the two sources and then hand-spread the chicken litter mix. September was the second cutting of hay for the plot. “We are trying to measure the biomass of our forage production. We’ve got a square called a quadrat, 25 centimeters by 25 centimeters, and shears, cutting out forage samples.” Bridges said, “We have one sample per plot. We have four treatments and five replications per treatment, so 20 plots.” The treatments include different rates of biochar and chicken litter. 

By weighing the samples collected, Bridges will be able to calculate the amount of forage production on a per-acre basis. Hayes said, “We are recording forage weights and tonnage per acre. She’s also collecting soil samples and keeping up with those because this will be a long-term project. Soil doesn’t just change overnight; it will take years and be a good project.” Biochar is high in carbon, and when it’s applied to the soil, it can be sequestered or stuck there for many years. That carbon can potentially increase the number of microorganisms in the soil. Those microorganisms play a very important role in plant growth.” 

Bridges said there is a lot of biochar research across the state. She adds that other research involves mixing biochar with fertilizers for row crops such as corn and rice.  

Bridges said, “They are also looking at using biochar in the chicken houses with the chicken litter or with the bedding in the chicken houses to see if it will help with reducing ammonia production because the ammonia burns the feet of the chickens, so they’re trying to use biochar as a way to reduce that. Using chicken litter from the chicken house with that biochar in it could be suitable for your plant production.” 

Hayes said the biochar product they used was light, and his part in this project is to try to make it easy for producers to incorporate biochar into their fertilizer program without needing any specialty equipment. Mixing the biochar with chicken litter, which farm producers already use, will be heavier and can be put into a spreader, where it will be mixed and applied on pastures or cropland evenly. 

Much research of the UADA and UAM College of Forestry, Agriculture, and Natural Resources is through public or private grants. Bridges said there is no grant money in this research project, at least not yet. This research is being done because Bridges and Hayes saw an opportunity to make a difference, had a few resources on hand, and knew that if successful, their work could lead to larger, grant-funded research that further helps farmers and the forest products industry. Bridges said Hayes approached her this spring about having access to these resources. “At the beginning of the summer, Scott came to me and said, ‘We’ve got access to the biochar; we got access to chicken litter, and we got access to a pasture. So, let’s go ahead and do this.’ And I said, OK.”  

Hayes said this hay-cutting was done early due to the summer heat. “We’re harvesting this now because we have not had significant rain in a few weeks. So, the forage quality begins to drop. You want to keep your forage quality as high as possible. Once you start with the high temperatures and low amounts of rainfall, the quality on your field tends to start crashing.” 

Bridges says it’s too early to tell what the results will find. She is still processing the samples and collecting data. 

Hayes said he was looking to help his fellow growers. “We’re just seeing what we can do to keep the agriculture alive here in Southeast Arkansas and make it good for our livestock and forestry guys.”