The residual effect of dual phosphorus placement on grain yield in southern NSW

Abstract

Key findings • Responses to residual phosphorus (P) were evident during the fourth cropping season. • Increase in grain yield is attributed to the higher P rates rather than placement depths. • The dual P placement provided little evidence of yield advantage (only in 2 out of 44 datasets) when compared with the same total P rate with shallow placement. • Shallow P was as effective or more effective than the dual P placement. • Placing P deeper in the soil profile might not be a reliable way of improving crop performance and P use efficiency in southern NSW.