Barley grass continues to be a major grass weed in cereal cropping regions on the upper Eyre Peninsula (EP). Swathing a cereal crop involves cutting and collecting the cereal crop and weeds into windrows at 20 to 40% grain moisture and allowing it to dry. Having the weed seeds cut and in the windrow before the seed heads shatter and before tillers fall over (lodging), may allow greater weed seed collection when using a chaff cart or windrows. Swathing early then harvesting for weed seed collection needs further evaluation as it may provide farmers with another tool for integrated weed management, especially for barley grass that matures and sheds seed before crops ripen.

• In 2019, approximately 40% of barley grass seeds had already dropped on the ground before the first swathing opportunity.
• Barley grass seed retention declines with every successive week and by crop maturity retained only 20% of its seed on the head.
• If growers are aiming to collect grass seed using harvest weed seed management strategies (chaff carts or windrows) they need to harvest grassy paddocks as early as possible to maximise weed seed collection.

Location: Condada: Matt Cook

Rainfall:L Av. Annual: 324 mm Av. GSR: 241 mm 2019 Total: 224 mm 2019 GSR: 209 mm

Paddock history 2019: Scepter wheat 2018: Emu Rock wheat 2017: Self-regenerating grass free medic pasture

Soil type Red Sandy loam

Plot size Paddock monitoring