Transformations of Carbon, Nitrogen, and Metals in Soils Treated with Waste Materials

Intact soil cores were used to evaluate decomposition, NH3 volatilization, N transformations, and metal movement in soils treated with sewage sludges and antibiotic processing wastes. Soil cores were leached monthly with water and incubated for 1 year. An insignificant amount (<1%) of the NH4+‐N applied was lost through NH3 volatilization. The addition of wastes to five soils established that soil properties did not influence decomposition. In contrast, appreciable differences in decomposition were observed when different wastes were added to the same soil. Significant amounts of NO3− were leached from soils treated with antibiotic wastes, while essentially no NO3− leaching occurred in soils receiving sewage sludge, suggesting that denitrification and/or immobilization are major N loss mechanisms in soils treated with sewage sludge. Minimal amounts of P and metals were leached from sludge‐amended soils. Soil analysis indicated that the majority of the added Zn, Cu, Cd, Ni, and Pb remained in the zone of sludge incorporation (0–7.5 cm) with minimal or no movement into the 7.5‐ to 15‐cm soil depth.