Dr. David Moseley

State Soybean Specialist|LSU AgCenter

2023 Abstract - LOUISIANA ON-FARM POTASSIUM TRIAL: Research from the LSU AgCenter and the University of Arkansas suggest there is an almost 100% probability soybean plants will respond to K applications in fields with very low to low potassium (K) soil-test levels, and there would be up to45% yield loss in the absence of a K application. On-farm soybean trials can be effective ways to demonstrate research-based recommendations on a producer’s farm. Due to recent high prices of K, applications of 70-80% of the recommended rates of K were proposed to be economical. In-season K applications based on critical leaf K concentrations can mitigate K deficiencies and improve yield potential. In 2022, a potassium formulation, rate, and timing trial was established on a Beauregard parish farm consisting of a sandy loam soil with very low potassium (K) soil-test concentration (26 ppm Mehlich-3Kfrom0 –6 inch soil depth). In addition to yield, leaf samples were collected at different growth stages to determine how the yield responded to in-season K applications. In addition, whole plant and seed samples were collected to analyze the K uptake for each treatment.