In areas of intensive animal production, P excreted in manures often exceeds local crop requirements. This has led to the current situation where soil test P is frequently above agronomic optimum values for crop growth. The most promising option to reduce P surpluses in the soils is by dietary modification, where the use of dietary additives (e.g., phytase enzymes) and reductions in over-feeding of P have been shown to decrease total and soluble P in manures. Our objective in this study is to evaluate how recent dietary alterations for dairy and poultry that are now receiving widespread adoption, and likely will become more common in the future, will affect P leaching through intact soil columns. The rationale for investigating P leaching from these soils is that changing the concentration and the forms of P in manures may alter the availability and transport of P in manure amended soils. Understanding these interactions is crucial so that the improved P use efficiency in confined animal feed operations through reduced P diets, can successfully be translated into reduced P losses from manure amended soils. For this experiment, we collected intact soil columns (30–cm diameter, 50–cm depth) from three typical Mid-Atlantic soils with Mehlich 3-P soil saturation from optimum to environmental M3-PSR category (0.11-0.16). Six treatments were established in a completely randomized block design, with three replicates for each soil. The columns received P fertilizer (superphosphate), two dairy manures generated from low (3.6 g/kg) and high (5.3 g/kg) P in diets, and two poultry manures generated from normal and reduced non-phytate P and phytase diets at 85 kg total P/ha. Then, columns were irrigated for 9 weeks, at weekly intervals, with equivalent of 50-mm of irrigation, and leachate was collected for analyses of different forms of P.