Testing crop row placement and pre-emergence herbicide options for brome grass on Mallee sand

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Brome grass is the costliest weed to grain production in the Mallee region despite herbicide resistance being relatively low. This paper brings together research trials from 2015 and 2016 addressing the potential for greater efficacy of pre-emergence herbicides on brome and the potential for better crop competition on non-wetting sands. For growers looking to often seed earlier and reduce reliance on Group B herbicides, pre-emergence herbicides can be an important part of brome management strategies but trifluralin often has limited efficacy. Previous trials at the MSF Karoonda site looking at a range of pre-emergence herbicides have shown the potential for greater than 75% brome control, but also the potential for variability under different early-season conditions. Improving crop competition can greatly improve herbicide efficacy. Other trials on non-wetting sandy soil at the Karoonda site have shown the potential for better crop establishment and large reductions in brome seed set suppression through seeding the crop on or near last year’s crop row (e.g. McBeath et al 2015). In 2016 the interactions between pre-emergence herbicide options and crop row placement were investigated.