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.

Good growing conditions in 2004 resulted in excellent first cut alfalfa hay yields, ranging from 1.4 t/A for the check to 2.3 t/A for the highest yielding treatment. The results showed that P and S were the major limiting nutrients. Second cut hay yields were lower due to an August frost, ranging from 0.5 to 1.0 t/A. Again, increasing the rate of S fertilizer, along with P, resulted in highest alfalfa hay yields. The August frost prevented seed formation of the alfalfa crop, leaving yields of less than 40 lb/A at harvest. 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