AUSTRALIAN grain growers are adopting alternative weed-management tactics to counter rising input costs such as fuel, fertiliser and herbicide.

Agronomists from the Grains Research and Development Corporation’s Weed Management Initiative report many growers have refocused on integrated approaches during global supply-chain disruptions, linked to the Middle East conflict, in recent months.

While herbicides play an integral role in crop protection, growers are increasingly using crop competition, optical spot-spraying and other interventions to reduce costs and improve herbicide efficiency.

WMI consulting agronomist and ADAMA Australia market development manager Bevan Addison urged farmers to speak with advisers to assess the economics of their weed-control programs.

“With input costs rising, there is an opportunity for growers to explore proven alternatives,” Mr Addison said.

ADAMA Australia agronomist and market development manager Bevan Addison. Photo: Seftons/GRDC

“Weeds are expensive to manage, so if new practices or adjustments in weed control tactics can reduce unnecessary spraying while maintaining yields, it’s worth speaking with an agronomist or other suitable adviser.”

He encouraged growers to look at basic interventions, such as referring to GRDC’s mixing and batching guide for herbicides and other products, to reduce the number of paddock passes.

Mr Addison warned that not all combinations are beneficial and that while some mixes work, care must be taken to not push beyond proven practices without understanding the risks.

As with all chemical application, label guidelines must be followed correctly.

“Skipping pre-emergent herbicides and relying on post-emergent options – particularly in canola and legumes – has led to poor weed control in some regions.

“Early treatments can sometimes improve the performance of follow-up applications.

“Getting the fundamentals right early is critical.

“Correct herbicide application remains one of the simplest and most effective ways to improve results.

“Higher water volumes and slower application speeds can significantly boost grass-weed control.

“Conversely, targeting broadleaf weeds in early stages of growth can improve herbicide performance, particularly where resistance is emerging.”

WMI consulting agronomist, Farmanco’s David Cameron, said favourable autumn rainfall in Western Australia created ideal conditions for early knockdown and double-knock weed control strategies, with many growers investing heavily in pre-emergent herbicides that performed well under good soil moisture.

Mr Cameron said reduced weed pressure in WA this season had given growers more flexibility, including the option to use lower cost herbicides or delay applications to capture multiple weed cohorts in a single pass.

Resources are available on GRDC’s website to strengthen these actions such as the WeedSmart Big 6, precision ag-tech guides, integrated weed management manuals and herbicide behaviour resources.

At Mollerin, 225km north-east of Perth in WA, Cathy Cooke grows crops including wheat, barley, oats, lupins and canola.

Ms Cooke and her family have been proactive in controlling weeds using several management approaches.

“It’s a multiple pronged approach we’ve adopted, so we’re not just reliant on herbicides or a single solution,” Ms Cooke said.

“One of the most simple and effective ways we’ve found to save costs is to allow our livestock to graze longer in the paddocks, which we see is beneficial for weed control and in some cases also keeps the soil in good condition for the next season of planting.”

GRDC manager weeds Sarah Morran said WMI research teams nationwide were focused on practical solutions to help growers manage herbicide resistance, adopt new technologies and reduce costs.

“Growers are time poor and margins can be tight. Small changes to sowing patterns, crop rotations or the timing of herbicide use can have real impact on the bottom line. Think of herbicides like fuel – only use what you need,” Ms Morran said.

Weed management is a persistent and costly challenge for Australian grain growers.

A conservative estimate of the annual cost to growers is approximately $4.1 billion in lost production and control measures, which equates to around $196/ha.

Source: GRDC