Improving Forage Production and Longevity of Alfalfa Stands with Balanced Fertilization

Alfalfa is a large consumer of phosphorus (P), potassium (K), and sulfur (S). In northeastern Saskatchewan, it is grown on approximately 200,000 acres for the dehydrated pellet market. Alfalfa for seed is grown on more than 120,000 acres in western Canada. In the absence of nutrient inputs, alfalfa cannot maintain its original productivity after about 3 years of hay production. The objective of this project is to determine the influence of balanced fertilization on alfalfa forage production, seed yield, and longevity of seed stands.

This research project was plagued with drought for the third year in a row in 2003, resulting in reduced hay and seed yields. Forage yields were low, with high variability among treatments and few significant responses. While not significant (p=0.10), alfalfa yield trended higher relative to the unfertilized check with P and K (27%; 0.17 t/A), and with a blend of P, K, and S (64%; 0.40 t/A). While alfalfa seed yields were very low (less than 80 lb/A), addition of P and K...or P, K, and S...significantly increased seed yields. The project is scheduled to continue for an additional year, during which time forage and seed yields will continue to be assessed relative to annual fertilizer applications. SK-26F