Effects of tall wheatgrass windbreaks on hay production of three alfalfa varieties at a semiarid location in Saskatchewan

Soil water limits alfalfa (Medicago sativa L.) growth in semi-arid southwest Saskatchewan. The dry matter yields of three alfalfa varieties with contrasting growth habits were compared when grown between tall wheatgrass [Thinopyrum ponticum (Podp.) Barkworth & D.H. Dewey] windbreaks spaced on 15-m centres, and when grown without windbreaks. Over a 7-yr period, and including the area occupied by the windbreaks, alfalfa yields were 2110 kg ha −1 dry matter on average. This was 40% more dry matter than from alfalfa grown outside the windbreaks. There were no consistent yield differences between the three varieties, but Beaver, a branch-rooted variety, produced more dry matter than Angus, a tap-rooted variety with fast regrowth potential, and Rangelander, a creeping-rooted variety, in the years when differences reached significance, and on average over the 7-yr period. Alfalfa regrowth was sufficient for a second cut in 3 of 7 yr. Cultivating to a depth of 35 cm with a Paraplow subsoiler prior to seeding had no effect on hay yields. Key words:Medicago sativa, dry matter yield, snow management