A pair of Florida researchers set out to explore the use of poultry litter biochar as a nutrient source for crop fields. What they found were short-term and long-term benefits — especially in soils where nutrient leaching is a common issue.

Biochar is made from poultry litter that is first dried and then heated in a low-oxygen environment using a process called pyrolysis. After cooling, the biochar can be ground into a finer powder. Biochar can be applied to fields as a nutrient source and, because it is dried and condensed, it is easier to transport longer distances than poultry litter.

University of Florida’s Andressa Freitas and Vimala Nair compared the use of poultry litter biochar to fields that received either inorganic phosphorus fertilizer or no additional phosphorus (the control). Two locations were studied: one with sandy, well-drained soil and another with coarser, nutrient-challenged soil. The cropping system included rye, corn, and sorghum.

In both locations, the poultry litter biochar matched or outperformed the inorganic phosphorus fertilizer in cumulative crop yields. Corn had a particularly positive response to the poultry litter biochar compared to the inorganic fertilizer, especially in the second year of the study. Corn is a nutrient demanding crop, so biochar’s ability to release phosphorus gradually may help deliver nutrients to corn at critical growth stages, the researchers noted. Rye and sorghum yield also benefited from the use of biochar compared to the inorganic fertilizer.

Plots receiving poultry litter biochar in the first year of the study had strong yields again in the second year, even with no additional phosphorus added. There was less residual effect from the inorganic phosphorus, making reapplication necessary to maintain yields. Therefore, the long-lasting impact of biochar could reduce input needs for farmers.

The researchers also found soil health benefits from the biochar, including additional macronutrients. Furthermore, its ability to release nutrients slowly reduces the risk of phosphorus runoff and leaching, making it a useful option for sandy soils that may struggle to retain nutrients. The research team noted that more studies are needed to determine application rates and understand the long-term effects in different environments.

This article appeared in the November 2025 issue of Journal of Nutrient Management on page 24.

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