Does applying phosphorus (P) both deep and shallow produce better crops than shallow P alone in southern NSW?

Abstract

Key findings •Fresh P fertiliser application outperformed the residual P effect in a P responsive site. •Both surface and subsoil Colwell P interact with the prevailing rainfall conditions to determine dual P or shallow P responses. •There was little evidence that dual P placement provided a yield advantage (only in one of the 3 data sets – wheat 2022 at French Park) compared with the same total P rate placed shallow. •Responses to the residual dual P placement were also evident during the third cropping year (2022) from the initial application year (2020).