Next to nitrogenphosphorus (P) is by far the most limiting nutrient in Nebraska for crop production. However, while nitrogen is limiting on most all soils for grain crops, native levels of phosphorus are adequate in many of Nebraska’s soils even for irrigated corn. This makes it important to know when to use phosphorus fertilizers and how to manage them for maximum effectiveness. If not, the return of the fertilizer investment is, for all practical purposes, lost.