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Title: Impact of precision application of ammonium nonanoate on weed control efficacy

Author
item Webber Iii, Charles
item TAYLOR, MERRITT - OSU - LANE, OK
item BRANDENBERGER, LYNN - OSU - STILLWATER, OK
item SHREFLER, JAMES - OSU - LANE, OK
item WELLS, LYNDA - OSU - STILLWATER, OK
item SHANNON, D. - UNIV. OF MISSOURI

Submitted to: International Conference on Precision Agriculture Abstracts & Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 4/15/2008
Publication Date: 7/24/2008
Citation: Webber III, C.L., Taylor, M.J., Brandenberger, L.P., Shrefler, J.W., Wells, L.K., Shannon, D.K. 2008. Impact of precision application of ammonium nonanoate on weed control efficacy. International Conference on Precision Agriculture, July 20-23, 2008, Denver, Colorado. Paper 441. CD-ROM.

Interpretive Summary: Racer (ammonium nonanoate) is a contact herbicide labeled for food use with efforts underway to label it as a herbicide for organically grown food crops. As a contact herbicide, precise chemical application will increase weed control efficacy while reducing crop injury. Precision application of herbicides is important to vegetable producers because there are a limited number of herbicides available and the potential for crop injury. The objective of this study was to investigate different nozzles, rates of active ingredients, and application volume for control of endemic weed populations. Initial research included 2 herbicide rates (6.4 and 9.6 lb ai/a) applied at 4 application volumes (17.5, 35, 70, and 105 gpa). In 2007, identical research studies were conducted at the Oklahoma State University Vegetable Research station in Bixby, OK and the Lane Agriculture Research and Extension Center at Lane, OK. Treatments included two nozzle types (8003 and 8005), three application concentrations of Racer (8.0, 11.2, and 14.4 lb ai/a), two application volumes (35 or 70 gpa), and an untreated control. Across locations, the overall impact of the nozzle selection was inconclusive. Racer had excellent control of carpetweed, but was less effective on cutleaf evening primrose. Racer weed control, with the exception of cutleaf evening primrose, was greater for broadleaf compared to grass weeds. The lowest Racer rate in 2006 and 2007 provided unsatisfactory control for all weed species.

Technical Abstract: Precision application of herbicides is important to vegetable producers because there are a limited number of herbicides available and the potential for crop injury. Racer (ammonium nonanoate) is a contact herbicide labeled for food use with efforts underway to label it as a herbicide for organically grown food crops. As a contact herbicide, precise chemical application will increase weed control efficacy while reducing crop injury. The objective of this study was to investigate different nozzles, rates of active ingredients, and application volume for control of endemic weed populations. Initial research included 2 herbicide rates (7.2 and 10.8 kg ai/ha) applied at 4 application volumes (164, 327, 654, and 981 L/ha). In 2007, identical research studies were conducted at the Oklahoma State University Vegetable Research station in Bixby, OK and the Lane Agriculture Research and Extension Center at Lane, OK. Treatments included two nozzle types (8003 and 8005), three application concentrations of Racer (9.0, 12.6, and 16.2 kg ai/ha), two application volumes (327 or 654 L/ha), and an untreated control. Across locations, the overall impact of the nozzle selection was inconclusive. Racer had excellent control of carpetweed, but was less effective on cutleaf evening primrose. Racer weed control, with the exception of cutleaf evening primrose, was greater for broadleaf compared to grass weeds. The lowest Racer rate in 2006 and 2007 provided unsatisfactory control for all weed species.