ABSTRACT

Nitrogen (N) transformation reactions leading to N availability in soils are biochemical in nature. These reactions are mediated by plant roots and microorganisms and catalyzed by soil enzymes. These reactions also depend on soil pH, temperature, ionic strength and presence or absence of activators or inhibitors, such as trace elements (TEs) in soils.. Even though studies have shown that broiler litter (BL) contains TEs, it remains the most widely used source of organic N in the Southeast of the United States. The objective of these studies was to assess the dynamics of inorganic N released in soils treated with trace element-enriched broiler litter (TEEBL) over a period of twelve weeks. Four reagent grade TE (As, Cr, Ni, and Se) solutions were mixed as single elements with a well characterized BL sample to give a concentration of 100 mmol TE kg^-1 BL. A batch incubation study was carried out in three surface soils (0-15 cm) mixed with the TEEBL to give a concentration of 300 mg N kg^-1 soil and incubated at 25 °C. At the end of each incubation time (0, 2, 4, 6, 8, 10, and 12 weeks), soil pH was measured and the inorganic N released was extracted and analyzed by ion chromatography. The N released varied with soil type, TEEBL applied and incubation time. At the end of 12 weeks, in the Hartsells soil treated with BL, the NH₄⁺ -N and NO₃^- -N released were 10.3 and 175 mg N kg^-1 soil, respectively.  While the TEEBL containing Cr reduced the NH₄⁺ -N and NO₃^- -N released to 4.71 and 125 mg N kg^-1 soil at the end of the 12 weeks, respectively.  In the Cecil soil, Ni inhibited nitrification by 20% while in the Appling soil, As inhibited nitrification by 43% at the end of 12-week.