Release of Inorganic Nitrogen and Phosphorus From Poultry Litter Amended with Acidified Biochars.

Georgia generates an average of two million Mg poultry litter (PL) annually. While this material is used as a fertilizer, its nitrogen (N) value could decrease considerably due to ammonia (NH₃) volatilization. One possible way of minimizing NH₃ volatilization from PL is by mixing it with biochar (or char), a by-product from bio-fuel production. When acidified, biochar may reduce NH₃ losses from PL. This study aimed to 1) evaluate the effect of acidified biochar on NH₃ volatilization, 2) examine its effect on CO₂ evolution and 3) determine its influence on the release of inorganic N and P from surface-applied or incorporated PL. Poultry litter with or without acidified biochars was surface-applied or incorporated into the soil. During the 21-d incubation, volatilized NH₃ and CO₂ evolved were determined at certain periods. Inorganic N and P were determined by leaching the soil with 0.01 M of CaCl₂ followed by a N- and P-free nutrient solution at 14 and 21 d of incubation. In addition to leaching, the treatments were extracted with 1 M KCl at the end of the incubation. Acidified biochars reduced NH₃ losses by 63% and CO₂ evolved by 21% from surface-applied PL. Similarly, it decreased NH₃ volatilized by 60% but increased CO₂ emission by 37% from incorporated PL. Adding acidified biochars did not affect the release of inorganic P from surface-applied or incorporated PL. Acidified biochars did not affect inorganic N released when PL was applied on the surface but increased it when PL was incorporated into the soil.