Last week I attended the Integrated Crop Management Conference at Iowa State University in Ames, Iowa. One of the more popular and crowded sessions during the two-day event was ISU agronomist Antonio Mallarino’s talk about making rational adjustment for nutrients phosphorus, potassium and lime given low prices for 2016.
Mallarino firmly believes that farmers should not cut or reduce phosphorus, potassium or lime application rates in low-testing soils, where yield increases and profits from fertilizer or liming are very likely even with unfavorable prices. However, he says farmers should also not fertilize high-testing soils and should not apply lime when soil pH is at or above levels that optimize crop yield. He adds that while soil testing is not a perfect diagnostic tool, it is very useful and even more relevant with unfavorable crop prices.
Check out these publications for details on soil fertility and soil sampling:
All slides/images/charts courtesy Antonio Mallarino.