NGN Better summer weed management decisions in southern and western Australia

Despite research and researchers promoting the importance and high expected returns of summer weed control it is clearly observed that substantial areas of summer weeds remain uncontrolled by growers. In the limited studies involving mainly heliotrope, grain yield losses due to water and N losses caused by summer weeds varied from 0 to 1.3 t/ha (Hunt and Kirkegaard 2010). Although 'generic' benefit: cost statements for summer weed control investment are often cited, returns from summer weed control are heavily influenced by a high level of uncertainty and risk (Hochman and Horan 2018). The returns can be highly variable due to seasonal variability in summer conditions, weed type and the following winter growing season. However, there is very little information able to be easily applied to understand differences between yields and seasonal probabilities. The primary aim of this investment is to better understand summer weed control and timing decisions by demonstrating likely economic benefit.