Effects of the Application of Balanced Phosphorus and Potassium Fertilizers on Alfalfa Yield and Yield Components

Alfalfa (Medicago sativa L.) stands normally provide the highest yield in their first two or three production years, and then start to decline thereafter, where sometimes re-establishing the stand becomes necessary. As re-establishing a stand is costly, it may be more profitable to improve management practices that will keep stands high yielding for more years. Towards that end, several research projects have been conducted in the low desert of Arizona. An on-farm study at Buckeye, Arizona indicated that application of phosphorus (P) fertilizer at 104 lb P2O5 per acre significantly increased (8.7%) hay yield (Ottman et al 2015). Other research has revealed that various phosphorus fertilizer sources had equal effect on alfalfa forage at equivalent rates of application (Burayu et al 2016) & (Brouder et al. 2005).