ARS | Publication request: Impact of precision applications of ammonium nonanoate on weed control efficacy

Submitted to: International Conference on Precision Agriculture Abstracts & Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: January 15, 2008
Publication Date: July 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 applications of ammonium nonanoate on weed control efficacy [abstract]. International Conference on Precision Agriculture, July 20-23, 2008, Denver, Colorado. Paper No. 441. p. 46.

Technical Abstract: Many factors contribute to the successful application of herbicides, including the herbicide’s mode of action, nozzle selection, application rate, application volume, weed species and weed maturity. The precision application of herbicides is especially important to commercial vegetable producers because of the limited number of herbicides available and the potential for crop injury. Weed control in organic vegetable production faces even greater challenges due to its dependence on cultural weed control methods rather than herbicides. Racer (ammonium nonanoate) is a contact herbicide labeled for non-food use, and efforts are currently underway to label it as a bio-herbicide for organically grown food crops. As a contact herbicide, the precise application of the chemical 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. The study was completed at the Oklahoma State University Vegetable Research station in Bixby, Oklahoma. Treatments included two nozzle types operated at recommended nozzle pressures (TeeJet XR8003 and TeeJet XR8005), three application rates of Racer (9.0, 12.6, and 16.2 kg ai/ha), and two application volumes (327 and 654 L/ha) for a total of 12 treatments. In general, Racer proved to be an effective contact herbicide for controlling the three weed species that were included in the study. The two higher rates of Racer (12.6 and 16.2 kg ai/ha) were more effective than the 9.0 kg ai/ha rate, although even the low rate resulted in higher levels of weed control than the untreated check. It appears that the overall spray application rate of 654 L/ha probably diluted the active ingredient enough to reduce its effectiveness. Although these preliminary results indicate that the 12.6 and 16.2 kg ai/ha herbicide rates applied at an application volume of 327 L/ha provided the best weed control, the research will be repeated to determine the consistency of the results.