Herbicide efficacy in retained stubble systems

Authors: Amanda Cook

Research Team: Ian Richter

SARDI, Minnipa Agricultural Centre

Funded By: GRDC EPF00001

Project Title: Maintaining profitable farming systems with retained stubble – upper Eyre Peninsula

Peer Review: Nigel Wilhelm (SARDI)

Key Words: herbicide efficacy, herbicides, stubble

Key Messages

• Dry seeding conditions and lack of rainfall at the start of the 2017 season resulted in challenging conditions for both establishing crops and weed control.
• Stubble residues reduced plant establishment and weed numbers; standing stubble in dry conditions had higher wheat germination than chained stubble.
• April dry sowing had lower wheat numbers than later sowings, which reduced grass weed competition during the season. Grass weed numbers were also higher and set more seed in the April sowing.
• No pre-emergent herbicide provided total barley grass weed control and keeping the weed seed bank low through other methods is important.
• Under the production regimes of upper EP, stubble management is unlikely to impact negatively on performance of pre-emergence herbicides targeting grass weed control, providing adequate water rates and best practice application techniques are used.