Nitrogen is one of the most frequently deficient nutrients in crop production and yet the most needed for growth. There has been a growing practice to use broiler litter (BL) to supply N in soils. The BL however, contains enzymes inhibitors namely trace elements that may accumulate over time with negative impacts on biochemical reactions. Studies have shown that addition of agricultural chemicals and industrial wastes to soils may trigger changes in soil enzyme activities. The mineralizing action of microorganisms is inseparably related to the activity of enzymes, which in turn has been proposed as indicators of soil health and quality. Their physiochemical state and role in biochemical reactions are dependent on pH, temperature, ionic strength, and presence or absence of activators or inhibitors such as trace elements (TEs). In this study we 1) Quantified the inorganic N released in an Appling surface soil treated with increasing amounts of trace element-enriched broiler litter (TEEBL), 2) Determined the threshold concentration of N at which nitrification is reduced by 50%, and 3) Used the threshold concentration to study N mineralization kinetics and enzyme activities in soils treated with TEEBL. A BL sample fully characterized in 19 TEs and N contents was used in this work. The BL sample was enriched in TEs (As, Cr, Cu, Mn, Ni, Se, and Zn) and applied to a previously characterized Appling soil and incubated for 21days at 25oC. The inorganic N released was determined and the threshold concentration at which nitrification was inhibited was identified and used to study N mineralization kinetics and TE inhibitory effects on enzyme activities. The enzymes studied are those involved in hydrolysis of native and added organic N to soils. Nitrification was inhibited by As and Zn (60% and 9%, respectively) while Ni and Se enhanced nitrification 1% and 4%, respectively.