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There were several take home messages from YP AG agriservices agronomist Darryn Schilling’s presentation.

His trial compared tined and disc seeding systems, and the effect different pre-emergent herbicides have on both crop effect and weed control.

Darryn ran the large group though an elaborate trial designed to answer the questions about what contributes to the least crop effect, while still giving an acceptable level of weed control, in particular, ryegrass control.

With recent resistance testing picking up annual ryegrass resistance to a lot of common pre-emergent herbicides, such as trifluralin, prosulfocarb and triallate, it leaves a limited number of herbicides available for ryegrass control, especially in a disc system.

Older products like trifluralin failed to control the resident ryegrass population adequately, with the resultant control poor due to measured resistance in the district of 30 to 95 per cent.

“When looking to make a pre-emergent herbicide choice to control annual ryegrass, it is important to know its resistance status, as well as the herbicide’s mobility and solubility in the soil,” Darryn said.

“We had a quite different start to the 2022 growing season, with a late break coupled with a some very heavy rainfall events.

“Some pre-emergent herbicides are quite water soluble, meaning they will move readily with the soil moisture band through the soil.

“Others are more mobile, where they are bound less onto soil or organic matter in or on the soil.”

The trial was done at the YP AG super site, as an opportunity arose to compare the landowner’s disc system, with that of the tined system on the YP AG trial seeder.

“The first step to the movement of the herbicide in the soil is to consider the soil texture, as well as be aware of the forecast rain pending,” Darryn said.

“Minimising soil throw by the seeding system will contribute greatly to crop safety, so growers are encouraged to be aware of how much soil throw is occurring by their seeder.

“This will vary from season to season, and soil type to soil type, depending on how much moisture is in the soil.

“Not all disc machines are the same, as some do not disturb the soil at all, while other throw as much soil as what a tined implement does.

“This is critical to know when choosing your pre-emergent herbicide, so you minimise any potential crop effect, like we have seen the previous couple of years.

“There is a fine line between crop effect and successful weed control, with that line changing every season.”

For any further information on the tined versus disc trial, or to have your annual ryegrass samples sent in for resistance testing, please speak to your local YP AG agronomist.