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Concern over nonpoint‐source phosphorus (P) losses from agricultural lands to surface waters has resulted in scrutiny of factors affecting P loss potential. A rainfall simulation study was conducted to quantify the effects of alternative P sources (dairy manure, poultry manure, swine slurry, and diammonium phosphate), application methods, and initial soil P concentrations on runoff P losses from three acidic soils (Buchanan–Hartleton, Hagerstown, and Lewbeach). Low P (12 to 26 mg kg⁻¹ Mehlich‐3 P) and high P (396 to 415 mg kg⁻¹ Mehlich‐3 P) members of each soil were amended with 100 kg total P ha⁻¹ from each of the four P sources either by surface application or mixing, and subjected to simulated rainfall (70 mm h⁻¹ to produce 30 min runoff). Phosphorus losses from fertilizer and manure applied to the soil surface differed significantly by source, with dissolved reactive phosphorus (DRP) accounting for 64 …