Soil phosphorus levels have increased as pork production has become concentrated. Phosphorus-based manure management regulations for land application have been proposed by policy makers. The objective of this study is to determine benefits/costs of adopting two alternatives for reducing phosphorus: synthetic amino acids or phytase. An optimization model is constructed to determine optimal excreted nitrogen and phosphorus from alternative feed ingredients. Results are derived using different manure storage and application systems. While the two alternatives are not least-cost ingredients, they become profitable when producers are constrained by land. An important result is that the net cost of manure is negative.