Many agricultural workers feel that 10-34-0 is a superior fertilizer for alfalfa since it is thought to move deeper in the soil with irrigation, be more available to the plant, and result in higher yields at equivalent rates compared to 11-52- 0. We found in our study with 24 cuttings over 3 years that alfalfa yields were similar if fertilized with 10-34-0 or 11-52-0 at equivalent rates. Total plant P was not affected by P fertilizer form or method of application. Broadcast 11- 52-0 resulted in higher soil P levels than water-run 10-34-0 and moved deeper in the soil profile. Broadcast 11-52-0 and water-run 10-34-0 appear to be equally effective P fertilizers for alfalfa in the irrigated southwest.