In trials that compared fields fertilized with synthetic fertilizer and those with chicken litter, Leandro Vieira and his team planted side-by-side plots. The chicken litter treatment generally produced greater aboveground biomass. Photos provided by Leandro Vieira II

A chicken producer’s trash can often be a row-crop farmer’s treasure.

For decades, Louisiana growers near the poultry farming industry have relied on the litter scraped off the floor of chicken houses as a low-cost source of fertilizer for their fields.

Now, LSU AgCenter soil fertility specialist Leandro Vieira II has begun studying how this chicken litter improves overall soil health and increases fertility while also adding organic matter to the soil.

“With fertilizer prices the way they are now and the different issues that are causing those to rise, something like chicken litter that is available locally might be of even more interest,” Vieira said.

The litter is composed of chicken excrement, spilled feed, feathers and the straw or other base materials laid on the chicken house floor. Chicken litter contains nitrogen, phosphorus and potassium, which are the primary nutrients found in fertilizers, along with vital macronutrients calcium, magnesium and sulfur, Vieira said. It also includes several micronutrients that aid in soil fertility, such as zinc, boron, copper and molybdenum.

“So, it is very complete,” Vieira said.

Many producers that rely on litter as fertilizer have raved about its benefits. At the AgCenter Macon Ridge Research Station in Winnsboro, Vieira has begun trials using chicken litter fertilizer in soybean and corn crops. He also collaborates on the project with Saulo Castro, a sugarcane and soybean agronomist with trials at the AgCenter Dean Lee Research Station.

“I am hoping that by adding all those nutrients plus organic matter, we can affect all the three properties of the soil — the chemistry by improving fertility, the physical part by increasing organic matter and the biological part by providing more nutrients and organic matter for those microorganisms to be able to mineralize even more nutrients in the soil,” Vieira said.

Vieira joined the AgCenter in 2024 as the soil fertility specialist for specialty and forage crops, and in April he transferred to Macon Ridge to serve as a soil fertility specialist for field crops.

While earning his doctorate at the University of Florida, Vieira studied the effects of biosolids on soil health, water quality, plant growth and crop yields. Biosolids are composed of sewage sludge that is composted and treated to be safely applied to fields and is mainly used in pastures, Vieira said.

Chicken litter shares similarities with his work on biosolids. In his studies, Vieira said he hopes to detail how chicken litter fertilizer can improve soybean and corn yields. If yields do not increase quickly, he expects the yield gains will eventually arrive because of added nutrients and other soil improvements.

“We are gaining organic matter that down the road will certainly help to keep our land more productive, especially on areas that have sandier soils, silt loam or areas that have been laser leveled, in which they remove that top soil and remove basically almost all the organic matter that they had before,” he said.

Preliminary results from Vieira’s first year of research have been promising. When applying chicken litter in one test field and inorganic fertilizers with the same amounts of nutrients in another field, yields for the chicken litter-treated field increased by 5%.

“Visually, I was seeing a higher number of pods per plant, and we decided to count,” Vieira said. “We sampled every single plot, and we got a 9% increase in the number of pods.”

Vieira cautions producers that not all chicken litters share the same nutrient content. Several factors can affect the nutrient composition of the litter, such as the number of chickens in a house, their feed and the types of straw or bedding materials used on the floor. Ideally, producers should have litter tested before applying, but that may not be practical for all farmers, Vieira said.

Through his studies funded by the Louisiana Soybean and Grain Research and Promotion Board, Vieira wants to clearly determine the viability of chicken litter for producers statewide.

“I don’t want everybody to apply chicken litter,” he said, “but I want people to know whether the properties of their soil will accommodate that kind of fertilizer source.”

Chicken litter is composed of chicken excrement, spilled feed, feathers and the straw or other base materials laid on the chicken house floor. It has been used as fertilizer in some regions of Louisiana for several years.

Through his studies funded by the Louisiana Soybean and Grain Research and Promotion Board, Leandro Vieira wants to clearly determine the viability of chicken litter for producers statewide.