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.


15 Mar 2001


    In northeastern Saskatchewan, alfalfa is grown on approximately 80,000 ha for the dehydrated alfalfa pellet market. On the prairies, alfalfa is the main forage seed crop grown, with 49,000 ha grown in western Canada at a value (including leaf-cutter bees) of approximately $50 million. Weed seed contamination of alfalfa seed results in significant losses in cleaning, lowers the certified seed grade and reduces the marketability of the seed. In addition, weed competition can result in substantial losses in hay and seed yield due to competition. Since this seed is the basis of the sun-dried and dehydrated hay industry, seed consumers will also benefit from the availability of weed free seed.

    Alfalfa can not maintain its original productivity after about 3 years. Because of low forage production or seed yields and infestation of weeds, about 20,000 ha of alfalfa hay fields and 4,000 ha of alfalfa seed fields are terminated every year in Saskatchewan, predominantly by tillage and herbicides. Termination of stands by this method increases the cost of production due to tillage, herbicides, reseeding, and can result in substantial N losses and soil erosion. The main reason of low production is the depletion of soil fertility, because alfalfa has very high requirements for P, S, K and some micronutrients (such as B). Many soils in this area are deficient in S and P. Boron deficiency is suspected on sandy soils low in organic matter, and some sandy soils contain insufficient amounts of K for high crop yields. Under poor fertility, alfalfa also can not compete with weeds. Improved soil fertility can make alfalfa out compete weeds and increase the longevity of stands by several years (Oohara et al. 1981; Burmester et al. 1991). This will also reduce the operational costs of production, prevent soil erosion and N losses, and increase productivity and quality of alfalfa.