The most important limiting nutrients in the alkaline clay soils are nitrogen, phosphorus and zinc.
Rainfall is quite variable resulting in enforced fallows and flexible 'opportunity cropping'.
Zn deficiencies in following crops. However, canola is a non-host of mycorrhiza. Sampling roots has shown much lower proportions of mycorrhiza in crops after canola than after other crops that are AM hosts. There was a highly significant correlation between biomass or head density of the wheat crop and level of mycorrhizal colonisation of the wheat roots. Similar experimental results were obtained with poor chickpea following canola compared with mycorrhizal host crops.