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ARS Home » Plains Area » El Reno, Oklahoma » Oklahoma and Central Plains Agricultural Research Center » Livestock, Forage and Pasture Management Research Unit » Research » Publications at this Location » Publication #394574

Research Project: Sustaining Southern Plains Landscapes through Improved Plant Genetics and Sound Forage-Livestock Production Systems

Location: Livestock, Forage and Pasture Management Research Unit

Title: Establishment of sand bluestem with the aid of pre-emergence-applied herbicides

item Boerman, Nicholas
item GILLEN, ROBERT - Kansas State University
item MASTERS, ROBERT - Corteva Agriscience

Submitted to: Crop, Forage & Turfgrass Management
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/26/2022
Publication Date: 11/2/2022
Citation: Boerman, N.A., Gillen, R.L., Masters, R.A. 2022. Establishment of sand bluestem with the aid of pre-emergence-applied herbicides. Crop, Forage & Turfgrass Management. 9(1). Article e20198.

Interpretive Summary: Establishment of native range grasses is critical for rehabilitation and restoration efforts on the Great Plains. One method for improving establishment is to reduce plant competition with undesirable plant species through use of herbicides. Sand bluestem is a native perennial grass species that is a critical component of native Great Plains rangelands. However, little work has been done to evaluate the impact of preemergence-applied herbicides on this species. Six preemergence-applied herbicides were evaluated at three trial sites in Northwest Oklahoma to determine their effect on sand bluestem stand establishment. One herbicide, thiazopyr, completely prevented sand bluestem establishment, whereas imazapic significantly increased stand establishment over an untreated control in all trial sites. Therefore, imazapic has potential for expanding the number of pre-emergent herbicides available for use in sand bluestem, while thiazopyr should be avoided when establishing sand bluestem.

Technical Abstract: Controlling competition with weeds is critical to successful native perennial grass establishment. Our objective was to determine the potential of several pre-emergence-applied herbicides to control annual weeds and aid sand bluestem (Andropogon hallii Hack.) establishment. Sand bluestem was seeded at one site in two adjacent areas during the end of March 2002 and 2003 in Woodward, OK, and at one site during the end of March 2004 near Fort Supply, OK, at 14.4 lb pure live seed acre-1 each year. Herbicides were applied within a few days of seeding and were watered in with ~0.75 inch irrigation water within 1 wk of application at the Woodward sites whereas no irrigation water was supplied at the site near Fort Supply. Response variables measured were sand bluestem stand frequency 13 mo after seeding and forage production 16 mo after seeding. Thiazopyr prevented ger-mination of sand bluestem in all plots, and atrazine + acetochlor produced stands significantly lower than the untreated controls in both locations. Imazapic produced stands of sand bluestem that were significantly greater than the untreated plots in both locations. Forage production of sand bluestem was significantly greater when imazapic was applied within7dafter seeding than in untreated plots at both loca-tions. Over all three sites, sand bluestem forage production averaged 3,202 lb acre-1 where imazapic was applied compared with only 1,663 lb acre-1 in plots not treated with herbicide. Sand bluestem forage production was consistently increased where imazapic was applied shortly after planting.