Integrating drift reduction technologies with agronomic practices

Date: March 2011
Term: 4 years
Status: Completed
Researcher(s): Eric Johnson, L. Nielsen and C. Gampe, Agriculture and Agri-Food Canada, Scott SK, T. Wolf and B. Caldwell, Agriculture and Agri-Food Canada, Saskatoon SK
SaskCanola Investment: n/a
Total Project Cost: n/a
Funding Partners: n/a

Project Summary

It is well known that a contact herbicide such as Liberty is less effective on hard-to-wet weeds such as wild oat or cleavers. Wild oat control can be improved by tank-mixing with a Group 1 graminicide; however, there are no tank-mixes that will improve control of cleavers. The objective of this experiment was to determine if twin nozzle configuration improved the efficacy of contact herbicides, compared to a single nozzle configuration. Five different field studies at the Scott Research Farm, showed no conclusive benefits to using a twin nozzle configuration over a single nozzle configuration in terms of improving the efficacy of contact herbicides such as Liberty.

It is well known that a contact herbicide such as Liberty is less effective on hard-to-wet weeds such as wild oat or cleavers. Wild oat control can be improved by tank-mixing with a Group 1 graminicide; however, there are no tank-mixes that will improve control of cleavers. Producers had identified the need to improve cleavers control in Liberty Link canola.

The objective of this probe experiment was to determine if nozzle configuration and boom height have an effect on wild oat and cleavers control in Liberty Link canola. Five different field studies were conducted from 2006 to 2009 at the Scott Research Farm to determine if twin nozzle configuration improved the efficacy of contact herbicides, compared to a single nozzle configuration.

Field studies in 2006 and 2007 evaluated several nozzles for control of wild oat, wild mustard, cleavers and kochia in Liberty Link 5020 hybrid canola to determine if double nozzles improved glufosinate activity on hard to kill weeds. Liberty was applied at 1.1 L/acre when the canola was in the 2 to 3 leaf stage.

The following nozzles were evaluated for control of broadleaf weeds in Liberty Link open pollinated canola:

In these studies, all of the nozzles resulted in greater than 90% control of the weeds present. The results showed that nozzle type did not affect canola yields. Overall there was no clear advantage to the double nozzle in this study

In the 2008 and 2009 field experiment, Liberty Link canola (cv 9590LL) was seeded in an area with inherent populations of wild oat and cleavers at a rate of 6 kg/ha. Liberty herbicide was applied using 2 rates (1.3 and 0.65 L/acre), 4 nozzle configurations (single fine, twin fine, single coarse, and twin coarse), and 2 boom heights (75 and 38 cm). The boom heights were set relative to the top of the target weeds. Liberty was applied slightly late (4-5 leaf stage of canola) to ensure that some treatments would fail. An untreated check was also included.

The 2008 study provided some indication that cleavers control may be improved (or at least equal to a standard fine spray quality) with a twin nozzle configuration set at a lower boom height; however, the test was repeated in 2009 and there was no improvement in cleavers control with twin nozzles or lowering boom height. Therefore, it appears that there are limited opportunities to improve cleavers control with Liberty by manipulating application parameters.

Figure 1: Effect of nozzle configuration and boom height on yield of Liberty Link canola. Liberty applied at 1.3 L/acre. Scott 2008.

Single Fine Single Coarse Twin Fine Twin Coarse Untreated

Nozzle configuration

Overall, the results from five different field studies conducted from 2006 to 2009 showed no clear advantage to using a twin nozzle in terms of improving weed control efficacy with contact herbicides such as Liberty, compared to single nozzle configuration.

A very coarse spray on the left, a medium spray on the right. Applied at 85 L/ha, dimensions of paper are 49 mm x 73 mm.

Source: T. Wolf, AAFC

A very coarse spray on the left, a medium spray on the right.

Source: T. Wolf, AAFC

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