Weeds were counted each year after emergence, at the same time that plant density was measured. In most cases, weed counts took place before post-emergent weed control (Figure 24). Unfortunately it was not possible to return to measure the efficacy of weed control.

Figure 24. Diagram of dates of sowing and weed control operations during the course of the project, compared to dates when counts of crop plants and weeds were made. Exact dates of some operations were unavailable and have been estimated.

Weed levels in-crop were generally low (Figure 25a-c), and in most cases crops were very clean at dry matter sampling at growth stage 30 (early stem elongation). The Patchewollock Till crop had a consistent grass (annual ryegrass) problem, but this was brought under control with break crops in 2007 and 2008. Annual ryegrass was also the main weed at Yaapeet No Till in 2007 and Donald No Till in 2008. Brome grass was the main weed in the Sea Lake Till paddock in 2008, Patchewollock No Till in 2007. It was present in all paddocks with grass in 2006, but was only found in two paddocks in 2007. 

Figure 25. Weed levels in-crop, measured at shortly after emergence (at the same time as plant density).

Summer weeds in 2007 tended to be higher in Till paddocks. This could reflect the extra germination stimuli provided by tillage, or higher overall populations.

Figure 26. Weed levels measured in early February, 2007.