Potential for foliar phosphorus fertilisation of dryland cereal crops: a review

Although not commonly used in dryland cropping systems to date, foliar phosphorus (P) fertilisation may allow a tactical response to prevailing seasonal climatic conditions, with the added benefit of reduced input costs at sowing. However, variable outcomes have been reported from field trials predominantly conducted in the USA, and to a lesser degree in Australia. The effectiveness of foliar P is dependent on soil P status, soil water status, crop type, fertiliser formulation and prevailing climatic conditions. This review argues that the potential of foliar P fertilisation in Australian dryland cereal cropping could be enhanced by altering formulations for enhanced leaf penetration using adjuvants, and by accurately assessing the responsiveness of sites before application. This review demonstrates that it is important to use appropriate techniques such as isotopic labelling, to measure the efficacy and mode of action of foliar formulations.