New Nest Egg: Poultry Litter Ash as a Fertilizer

By Lupe Chavez
January 4, 2002

Medieval alchemists might have failed at finding a recipe for making gold, but an Agricultural Research Service scientist changed poultry litter ash into money. The potential profits from this transformation could bring a change of luck for farmers.

Eton Codling, a soil scientist with the Agricultural Research Service’s Henry A. Wallace Beltsville (Maryland) Agricultural Research Center, in cooperation with the Maryland Department of Natural Resources, discovered that ash from power plants burning poultry litter for electricity makes a good fertilizer. This alternative for handling poultry litter could help the environment, promote better plant growth and reduce costs for farmers.

In experiments at the Animal Manure and By-Products Laboratory, ARS researchers grew wheat in limed and non-limed soils fertilized with poultry ash and potassium phosphate. Plants grown in soils treated with ash fertilizer had higher amounts of phosphorous in plant tissue, meaning the nutrient was readily available for uptake by roots.

This research was stimulated by the Maryland Water Quality Act of 1998, which limits poultry litter use on farmland. Excess phosphorous in soils can result in storm water runoff and drainage waters dangerous to the Chesapeake Bay watershed. The law encourages alternative uses for poultry manure, including burning it to produce electricity. Codling began his research by asking a simple question at a power plant burning poultry litter: "What are you going to do with the ash?"

Litter ash has interesting characteristics, beginning with its low solubility in water. The ash has a higher total concentration of phosphorous than poultry manure because the burning process removes organic matter and water. The ash also reduces farmers’ costs because it is lighter than chicken litter and easier to transport to areas where such fertilizer is needed.

Further studies are needed to determine the optimal levels of litter ash for wheat production and to establish the economic value to farmers. If these studies with wheat are successful, other crops will be considered for similar research.

ARS is the U.S. Department of Agriculture's chief scientific research agency.