Although cereal-intensive cropping has been demonstrated to be productive in the Mallee, there are situations where grass weeds, disease and high fertiliser costs may necessitate a break crop option. This trial was designed to evaluate the effect of a range of break crops and pasture over a range of mallee soils over 3 years of subsequent wheat. In replicated field trials at the Karoonda (Lowaldie) site, break crops including legume, rye, brassica and pasture were grown in 2009 and 2010 and followed by consecutive wheat crops until 2013. Wheat yield following these breaks were compared with a continuous wheat treatment. All treatments were applied at four positions in the landscape: hill (deep sand), mid-top, mid-slope and swale (heavy flat).

• Average wheat yield gains were approximately 0.6 t/ha in the first year after a break and the size of this yield gain was similar in high and low yielding seasons.
• Second year break effects were generally in the order of 0.3 t/ha and third year break effects 0.1 t/ha, resulting in a total of approximately 1 t/ha more wheat being produced following a break compared to continuous wheat.
• The effect of breaks on subsequent wheat yields is usually more consistent across soils, seasons and break type than the yield of break crops.
• Cumulative gross margins from wheat following legume, brassica and legume-based pasture breaks were generally much higher than continuous wheat, but the overall profitability of including breaks is strongly determined by the high variability in the relative profit from the different break options on different soils in the year that they are grown.