DIRECT SEEDING OF ALFALFA INTO ESTABLISHED RUSSIAN WILDRYE PASTURE INSOUTHWEST SASKATCHEWAN

Experiments were started in each of the three years 1989-1991 to exami ne the effect of severing near-surface roots of established Russian wi ldrye (Psathyrostachys juncea (Fisch.) Nevskii) on the establishment o f two alfalfa cultivars (Medicago sativa L.) in semiarid Saskatchewan. In 2 of 3 yr, up to 75% more seedlings were established of the cultiv ar Rangelander, a creeping-rooted alfalfa of mixed ssp, sativa (L.) Le sins and Lesins and ssp. falcata (L.) Arcangeli parentage, than of SCM f3713, a tap-rooted ssp. falcata. Severing Russian wildrye roots signi ficantly improved alfalfa establishment and dry matter production in 1 990, only 1 of 3 yr. There were no benefits from severing Russian wild rye roots on more than the side adjacent to the alfalfa seedlings. Soi l moisture levels in the top 15 cm of soil were at or below the perman ent wilting point through much of the growing seasons of 1989 and 1991 . Soil moisture was increased only occasionally where Russian wildrye roots were severed.