Application of poultry litter at agronomic rates is the key to control nutrient runoff losses from cropland receiving the organic waste. To establish agronomic application rates, nutrient release and supplying capacity of poultry litter following land application has to be addressed first.  Alum-amended (106 g Al₂(SO₄)₃• 14H₂O kg^-1 dry litter) and untreated poultry litters were packed in PVC columns (6" i.d.) at 110 tons ha^-1 to a depth of 2" and weathered in the field for 15 months.  Leachate was collected and analyzed for various nutrients.  The poultry litter leachate contained high concentrations of dissolved organic carbon (DOC, 33-11800 mg L^-1), dissolved nitrogen (6-2700 mg L^-1), dissolved phosphorus (50-224 mg L^-1), potassium (20-6000 mg L^-1), and other inorganic salts.  In 15 months of field decomposition, per kg of non-treated poultry litter released 121.7 g of dissolved organic carbon (DOC), 34.9 g of nitrogen (N, 14.9 g in NH₄⁺, 0.4 g in NO₃^-, and 0.13 g in NO₂^-), 11.5 g of phosphorus (P, 10.1 g in inorganic P), and 111.6 g of potassium (K) in the leachate; the alum-treated litter released (per kg) 64.3 g of DOC, 41.4 g of N(31.2 g in NH₄⁺, 2.2 g in NO₃^-, and 0.06 g in NO₂^-), 1.8 g of P (1.1 g in inorganic P), and 122.4 g of K.  The nutrient release occurred predominately in the first three months following litter application.  Release kinetics of DOC, total dissolved N, NH₄⁺-N, and K could be described by a first order Exponential Rise to Maximum model, while total dissolved P and inorganic P by a Power equation, and NO₃^- and NO₂^- by a Sigmoidal process. To control nutrient runoff losses from land-applied poultry litter, environmentally benign agronomic application rates should be developed accordingly.