MANAGING PHOSPHORUS FOR MAXIMUM ALFALFA YIELD AND QUALITY

Maintenance of an adequate plant nutrient supply is essential for production of high-yield and high-quality alfalfa. Alfalfa production removes large amounts of nutrients from the soil than must be periodically replaced to remain sustainable. Since P has essential biochemical roles in alfalfa, both yield and quality are reduced when this nutrient is deficient. Nitrogen fixation is also suppressed when P supplies are limited. Soil P concentrations should be measured and limitations corrected prior to crop establishment. Regular P additions will likely be required to replace harvested nutrients, as guided by tissue testing. There are no major differences in P fertilizer source or form for alfalfa and a variety of application methods can be used to meet the nutrient demand of the crop