1. Potassium Recalibration for Corn in North Dakota and Sampling Time

Potassium (K) fertilizer recommendations for corn (Zea mays, L.) are commonly guided by yield response calibrations to soil K levels; however, sample drying and time of soil sampling have been shown to affect the amount of extractable K. Potassium rate trials were established at 13 locations in southeastern North Dakota during 2015 with objectives to evaluate soil K testing methods and their relationship with corn yield response to K fertilization and to assess temporal soil K variation.... J. Breker, D. Franzen