Due to the increased importance of conservation tillage and erosion control for agronomic and environmental P management there is a need for a better understanding of its cycling in agricultural systems under no-till production.  A study established in 1994 at five locations across Iowa has been conducted to gain a better understanding of P dynamics in corn-soybean rotations.  The study used broadcast and planter-band placement methods and multiple P rates to determine long-term effects on soil P, grain yield, and P removal with harvest.  Phosphorus rates based on existing estimates of P removal maintained or slightly increased soil-test P, while those above and below increased and decreased it.  The P placement had a negligible effect on yield except for an occasional and small advantage of banding due to dry conditions in surface soil, but did have a significant effect on reducing stratification.  Results showed that P fertilization increased P removal through effects on both yield and grain P concentration.  However, grain P concentration was uncorrelated with grain yield and poorly correlated with soil-test P. Average grain P concentration estimates used in Iowa for soil P maintenance (3.0 and 6.5 g P kg^-1 for corn and soybean) were among the highest concentrations observed.