Submitted to: Society for Range Management Meeting Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 9/1/2005
Publication Date: 2/1/2006
Citation: Gillen, R.L., Masters, R. 2006. Preemergence-applied herbicides aid sand bluestem establishment [abstract]. Society for Range Management 59th Annual Meeting, February 11-17, 2006, Vancouver, Canada. Abstract No. 127. p. 84. 2006 CDROM. Interpretive Summary: Not required.
Technical Abstract: Controlling plant competition is critical to successful perennial grass establishment. Our objective was to determine the potential of several preemergence-applied herbicides to control annual weeds and aid sand bluestem (Andropogon hallii Hack.) establishment. Sand bluestem was seeded at the end of March each year from 2002 to 2004 at 10 kg pure-live-seed ha-1. Herbicides were applied within a few days of seeding and included: thiazopyr at 0.56 or 1.12 kg ha-1; acetochlor at 1.79 kg ha-1; acetochlor at 1.68 kg ha-1 + atrazine at 1.12 kg ha-1; S-metolachlor at 1.61 kg ha-1 + atrazine at 2.08 kg ha-1; imazapic at 0.035 or 0.053 kg ha-1; and dithiopyr at 0.42 kg ha-1. Response variables measured were sand bluestem stand frequency 13 months after seeding and standing crop 16 months after seeding. Thiazopyr and acetochlor+atrazine reduced the frequency of sand bluestem seedlings compared to stands in plots not treated with herbicide. Seedling frequencies in plots treated with the other herbicides and plots not treated with herbicide were not different when 75 mm of water was applied within 1 week of herbicide applications. Standing crop of sand bluestem was increased where S-metolachlor+atrazine or dithiopyr were applied after seeding in 1 of 3 experiments. Over all experiments, sand bluestem standing crop averaged 5100 kg ha-1 where imazapic was applied at 0.035 or 0.053 kg ha-1 compared to only 2550 kg ha-1 in plots not treated with herbicide. Sand bluestem establishment was consistently successful where imazapic was applied shortly after planting.