Increasing corn yield and harvest of cornstalks for feed, bedding or bioenergy production are generating numerous questions about phosphorus (P) and potassium (K) concentrations in cornstalks and removal. The functions of P and K in plants influence their accumulation in different plant parts, and also may influence the magnitude of losses from live tissue or residue. A larger proportion of the total plant P is in grain compared with K, and most of the absorbed P is incorporated into the plant organic matter but K is in the inorganic soluble ion form. Therefore, P and K amounts removed by cornstalk harvest, concentrations and recycling to the soil may vary and over time be affected by rainfall and other factors. Also, high temporal soil-test variation, mainly for K, points to a potentially important effect of P and K recycling.