Nitrogen, phosphorus and carbon transformations in a coastal plain soil treated with animal manures

Abstract

A laboratory study was conducted to evaluate nitrogen, phosphorus and carbon transformations in a coastal plain soil (Norfolk sandy loam) treated with animal manures. Three types of manure—beef, poultry and swine—were either surface applied or incorporated into the soil. The results indicate that losses of ammonia N through volatilisation were higher in the soil treated with poultry manure than in the soil treated with beef or swine manures. Poultry and swine manure applications resulted in the accumulation of approximately the same amount of nitrate N. Accumulation of nitrate N in the soil treated with beef manure was approximately half that in the soil treated with poultry or swine manure. Application of animal manures to the soil increased soluble organic N, soluble P and soluble organic C. Application of all the manures increased the denitrification potential of the soil. The denitrification potential of the Norfolk soil was higher when treated with beef manure than when treated with poultry or swine manures. Denitrification potential was highest in the treatment where animal manures underwent 30-day decomposition. The nitrate N loss decreased as the manure decomposition periods were increased to 60, 90 and 120 days.