Bermudagrass Yield Response to Nitrogen and Potassium Fertilization in Northwest Arkansas

Potassium performs a vital role in maintaining yield potential and stand persistence of bermudagrass ( Cynodon dactylon L.) making proper fertilization critical for sustainable hay production. Our primary objective was to demonstrate how N and K fertilizer rates influence bermudagrass yield and soil‐test K across a four‐year period. Each year, N was applied at 180 and 300 lb/acre in three equal split applications in combination with K 2 O at 0 and 180 lb/acre. Potassium fertilization maintained soil‐test K between 157 to 160 ppm (optimum). When no K was applied, soil‐test K declined to 62 ppm (low) in fall 2007 following the fourth year of study. On average, forage yields were increased 25% by increasing N rate from 180 to 300 lb of N per acre/year and 12% by increasing K rate from 0 to 180 lb of K 2 O per acre/year, respectively. Forage yield per unit of N fertilizer also decreased from 42 to 36 lb of forage per pound of N when no K was applied. Proper K fertilization is essential for maximizing forage utilization of N fertilizer and maintaining soil K fertility on low cation exchange capacity soils in northwestern Arkansas.