Better Crops: The Fertility of North American Soils: A Preliminary Look at 2015 Results

The 2015 soil test summary is the fourth in a series of summaries dating back to 2001, 2005, and 2010. For the first time, trends in relative frequencies in soil test levels are being examined.

Preliminary results for Corn Belt states are showing a reduction in percentages of samples testing high in P, but an increase in samples testing low, reflecting a greater need for P fertilization. For K, ranges with the highest percentages of samples, as well as their changes over time, are in general agreement with university recommendations.