Authors: Amanda Cook
Research Team: Ian Richter, Sue Budarick and Wade Shepperd
SARDI, Minnipa Agricultural Centre
Funded By: SAGIT S614.
Project Title: Improving fertiliser efficiency and reducing disease impacts using fluid delivery systems,
Peer Review: Nigel Wilhelm (SARDI)
- Phosphoric acid as a liquid fertiliser resulted in 13% and 8% higher yields in 2014 and 2015 respectively at Streaky Bay, and an 8% yield increase at Warramboo in 2016 when compared to the same rate of P delivered in granular fertilisers.
- Despite the yield increases at Streaky Bay and Warramboo the economics showed granular fertiliser had greater returns in $/ha compared to using phosphoric acid at 9 units of P.
- The guidelines for moving to the adoption of phosphoric acid as a P source exist in the Fluid Fertiliser Manual which adequately covers the principles, economics, recommendations and chemistry of adopting fluid delivery systems. The manual is available at fluidfertilisers.com.au.
- Knowing the responsiveness of a soil type to phosphoric acid is an important factor to consider before investing in a fluid delivery system. The responsive soil types are generally higher in calcium carbonate (greater than 25%). P source responses may also be driven by soil moisture conditions because in 2016, which had wetter seasonal conditions, phosphoric acid and granular P performed similarly in the same soil type at Streaky Bay.
- The adoption of fluid fertiliser systems to place fungicides in-furrow for rhizoctonia disease management is not recommended in this environment. The addition of fungicides showed small and variable yield advantages at Warramboo in 2014 and 2016 and Streaky Bay in 2016. Using fungicides in above average seasons the greatest yield benefit was only 0.22 t/ha with an in-furrow split application with granular phosphorus and trace elements. Including fungicides on wheat up front will increase input costs and risk over a large cropping program.
- Large scale demonstrations by growers across Eyre Peninsula with in-furrow fungicide applications at seeding did not reduce rhizoctonia or produce yield benefits over three seasons.