WEEDICIDE PROPERTIES OF TRASH BLANKETS AND TIMING OF APPLICATION OF PRE-EMERGENT HERBICIDES ON TRASH

THE EFFICACY OF some pre-emergent herbicides when applied on a green cane trash blanket (GCTB) has been established, but their relevance in terms of yield and profit increase is still disputable. Three trials were implemented in 2010 in the Mackay area to study the impact of different GCTB levels on the weed population and cane yield. Cane yield was higher when grown with a GCTB compared to bare soil. There was no significant yield difference between trash treatments, but there was a trend in favour of the thicker trash levels. The management of broadleaf weeds and grasses improved with an increasing level of trash. Growth of vines was slowed down by the thickest trash level only. Two other trials compared different strategies in ratoons including preemergent herbicides applied at different periods. Variable outcomes were obtained in each trial but slightly better cane yields were obtained with strategies including an early pre-emergent herbicide. Strategies including an early pre-emergent herbicide were more efficient to control the weed population.