Reseeding Trials on Columbia Basin Rangelands Dominated by Winter Annual Grasses

Abstract

From 1960 to 1975, a series of trials on the eastern side of the Columbia Basin north of the Snake River was conducted to determine the feasibility of establishing crested wheatgrass on rangelands now dominated by downy brome and medusahead. Excellent annual grass and annual broadleaf weed control was obtained with several herbicides, with atrazine at 1:1 kg/ha as a fallow treatment before seeding being the most satisfactory. Seeding in late autumn or early spring with a rangeland drill, modified to give some seedbed preparation in the row, combined with annual weed control, generally provided favorable conditions for germination and emergence of crested wheatgrass seedlings. However, seedlings failed to become established in most experiments. Trials with a soil fumigant, methyl bromide, resulted in excellent stands of established plants and presented strong evidence that with seedling plants under environmental stress, microbiological factors may be a primary cause of seedling failure.