Rainfall, rotations and residue level affect no-tillage wheat yield and gross margin in a Mediterranean-type environment

Monoculture wheat and cereal rotation had the highest cumulative 9-year average gross margins, despite the diverse rotation showing higher grain protein concentration in most years and improved wheat yield over time. Lower gross margins in the diverse rotation were associated with poor legume performance in many years and low canola yields in dry seasons. Improving the reliability of these break crops in this growing environment is the key to increasing their uptake by farmers. Cover crops in the rotation negatively impacted gross margins, without any observed yield benefits in the following years, therefore should not be recommended to replace the one cash crop per year in this low rainfall Mediterranean-type environment.