Summary This paper outlines a project that intends to investigate the link between the occurrences of weeds in pasture hay crops and weed seeds in bales. Noxious weed in particular pose a threat to the livelihoods of primary producers in this manner. As an example of a noxious weed, this project will investigate Nassella neesiana, Chilean needle grass. This species is a restricted (noxious) weed that infests roadsides, native grasslands and pastures that may be baled for hay. In Victoria it has the potential to cause significant economic harm to agricultural areas and the trade in fodder and hay. This project aims to develop methods for the detection of weed seeds in hay bales and provide more information about the role of hay machinery in their spread. Later, we will investigate the extent of seed shedding from hay bales during transportation by road. This project will attempt to correlate the percentage cover of N. neesiana prior to harvest with the seed content of bales. Trial core samples from bales indicate that seeds of N. neesiana and other grass species were present. However, a correlation has not yet been established between weed biomass and the seed content of bales.
It has been observed that the seeds of Chilean needle grass (Nassela neesiana) can be spread by the use of machinery to slash or mow roadsides that are infested with this weed. Modification of slashers by the addition of a cover or deck fans that can prevent seed and/or seed heads settling on the top of the slasher appears to be effective. This project compared the relative effectiveness of each type in a Chliean needle grass infestation at a demonstration day held at Greenvale, Victoria, Australia in November 2009.