As might be expected, chemical use was higher in the No Till paddocks (Table 18-Table 23). Partly this relates to fewer crops grown in Till paddocks, as well as greater substitution of tillage and grazing for weed control. Because of the range of products the only way this can be summarised is in cost, although the tables of chemicals used Table 18-Table 23) also illustrate the difference fairly well.

Herbicide rates (for example Glyphosate 450) tended to be quite robust in both Till and No Till paddocks; the lowest Glyphosate 450 rates used were in the Patchewollock Till paddock. Most glyphosate was applied with some sort of spike.

Herbicide resistance in any system is driven by the survival of plants carrying resistance genes. A key driver for past resistance development in No-Till systems has been in-crop survival of weeds that were tolerant of pre-sowing knockdowns. The prescribed solution to this is the ‘double knock’, but there was no evidence of this in the focus paddocks. Similarly, survival of tolerant weeds after fallow commencement herbicides (in fallows) and grass selectives (in crop) has been a cause of resistance development in Till systems. Survival of tolerant weeds on fallows may have been an issue.

Table 18. Chemical use in the Culgoa focus paddocks.

Table 19. Chemical use in the Donald focus paddocks.

Table 20. Chemical use in the Minyip focus paddocks.

Table 21. Chemical use in the Patchewollock focus paddocks.

Table 22. Chemical use in the Sea Lake focus paddocks.

Table 23. Chemical use in the Yaapeet focus paddocks.