Peanut cultivar response to residual soil test potassium in North Mississippi

Abstract

The average U.S. peanut (Arachis hypogaea L.) yield has increased by approximately 25% with the adoption of peanut cultivar ‘Georgia-06G’. Since this adoption, many new high yielding runner cultivars with similar yield potential have been released. However, current nutrient recommendations are based on soil tests that were developed prior to the release of Georgia-06G. Particularly for potassium, current soil test potassium (STK) critical values were established on soil textures with relatively low cation exchange capacity (CEC) but were not validated on soil textures with high CEC. This study aimed to evaluate the growth and yield response of five recently released peanut cultivars to four STK levels ranging from very low to medium based on Mississippi State University Extension soil testing recommendations. The STK classification levels were also based on two soil series categorized with high CEC—Leeper (∼38.4 meq 100 g⁻¹) and Marietta (∼15.9 meq 100 g⁻¹) soil series. Cultivars Georgia-06G, ‘Georgia-16HO’, ‘Georgia-18RU’, FloRun ‘331’, and ‘AU-NPL-17’ were evaluated in this study. No STK × variety interaction occurred, indicating similar K requirements across all varieties evaluated. However, a positive pod yield response occurred in both soil types when the average STK increased from 128 to 167 lbs ac⁻¹ for all cultivars and site years. Critical STK values on both soils were greater than many current Extension recommendations, and the critical STK value of Leeper is greater than the Marietta soil series, likely due to the higher CEC value. These results demonstrate the need to adjust peanut STK sufficiency levels based on soil CEC. Further evaluation of modern peanut cultivar productivity response to STK sufficiency levels is needed for soils with moderate CEC.