Soil Mineralogy and Possible Influence on Potassium Fertilizer Response in North Dakota.

Potassium nutrition in corn has only recently been explored seriously in North Dakota. In the first year of work, the dry K test and moist K test were only partially effective in predicting corn K response over ten locations. Sites that were 'high' in K responded, while several that were 'low' in K did not respond. A quantitative analysis of soil clay species and soil potassium feldspar content helped to explain one of the responding high K sites and two of the non-responsive K sites. Novel K analysis and calibration may be needed in the future to better predict the probability of K response in corn in North Dakota.