Source: University of Illinois at Urbana-Champaign

With the high price of fertilizers and the late harvest last fall, many fields did not receive the typical phosphorus (P) or potassium (K) applications. The question being asked is, Should I apply these nutrients this spring? The answer depends on several factors. The guiding principle in fertilizer decisions is that you should definitely apply nutrients when the chance for yield increase is large and the expected yield will pay for at least the cost of the fertilizer.

Soil test information is important in guiding these decisions. The critical level for a nutrient is the point at which its application will result in a significant increase in yield, or the point at which withholding its application will result in a large decrease in yield.

For more, click here.