Rotational impact of Mallee grain legume crops on wheat

Ivan Mock, Dodgshun Medlin

Introduction
Inclusion of legume crops in the rotation has been associated with biological processes including nitrogen fixation, disease suppression and potential for improved weed control which combine to benefit subsequent crops. Production of legume crops in Mallee environments has however been constrained by the demise of pasture legumes in crop intensive rotations and inconsistent yields and therefore higher risks with grain legumes.
Two sites established in 2013 evaluated and demonstrated that appropriate grain legume crops can be successfully grown in dryland Mallee environments when modern varieties and appropriate agronomic systems, including inoculation with bradyrhizobia, are incorporated.
Both sites were re-sown to wheat in 2014 as a bioassay of the rotational benefits of the 2013 legume crops. 2013 results have previously been reported (Mock, 2014) although 2013 legume yields are included in this report to provide a context for 2014 wheat results.