Unlike corn and soybeans, obtaining accurate yield information for forage crops involves considerable planning, time, and effort on behalf of the person collecting the yield data and the farmer. Historically, few producers had the capacity or patience during harvest to undertake such a task. Most efforts to measure alfalfa yield in the past were usually limited to the best small area of the best field. Currently, many larger dairies have installed on-farm scales for measuring purchased production of forages and/or feed commodities. These scales now make it relatively easy to weigh production not just from small areas of fields, but entire fields over the course of several years.
Soil Science Extension
University of Wisconsin Madison