Improving Forage Production and Longevity of Alfalfa Stands with Balanced Fertilization

To determine the influence of balanced fertilization on forage production, longevity of alfalfa stands, weed population and disease severity.

IPNI-2000-CAN-SK26

01 May 2002

2001 Annual Interpretive Summary

Improving Forage Production and Longevity of Alfalfa Stands with Balanced Fertilization, 2001

Alfalfa is a large consumer of phosphorus (P) and potassium (K). In northeastern Saskatchewan, it is grown on approximately 200,000 acres for the dehydrated pellet market. Alfalfa for seed is grown on over 120,000 acres in western Canada. In the absence of nutrient inputs, it cannot maintain its original productivity after about three years of production. Improved soil fertility can help it out-compete weeds and increase the longevity of stands by several years.

This research was initiated to determine the influence of balanced fertilization on alfalfa production, seed yield, longevity of seed stands, weed populations, and disease severity. Low levels of stored soil water and very poor rainfall during the growing season left little opportunity for much of a forage or seed alfalfa yield in 2001. While none of these responses were significant (cv = 31 percent), hay yield trended higher with addition of P and K, or P, K, and sulfur (S). Alfalfa seed yields were not only low (<50 lb/A), but the high variability between treatments provided little information from the 2001 production year. Ratings of the stand for weed populations and disease also revealed no differences. Continued monitoring of this site will help to identify the rate of nutrient drawdown by the alfalfa and its impact on alfalfa hay and seed yield and quality. SK-26F