Improved crop varieties have been delivering higher and higher yields, even some surprisingly impressive yields in recent dry years. Along with higher yields comes higher crop removal of phosphorus and potassium. These graphs demonstrate how high-yielding crops can remove more P and K than typical yields from 20 or 30 years ago. If your fertilization strategy has not changed (e.g., only starter P for wheat), you may be removing more P than you are adding. To keep soil fertility levels from dropping, be sure that you are adjusting P and K rates to account for higher crop removal. Soybean is an exceptionally large K exporter, over twice as much as a good wheat yield. If you grow soybean, watch soil test K over time; you may be removing K faster than you think!