NESP TWQ Round 5 - Project 5.11 – Improved water quality outcomes from on-farm nitrogen management

The sugar industry occupies 350,000ha in Reef catchments, applies >55,000t of nitrogen (N) fertilizer annually and is a major contributor of dissolved inorganic nitrogen (DIN) to Great Barrier Reef receiving waters. There are many potential mechanisms for reducing on-farm Nusage. However, the comprehensive review of N use in sugarcane (SRA/DoE 2014) identified widespread over-use of N fertilizer and recommended adopting production zone yield potential (PZYP) combined with enhanced efficiency fertilizers (EEFs) to reduce ’surplus N’ (where applied N>crop requirements). This project is utilizing existing farm trials at identified N loss ‘hot spots’ to test PZYP as the basis for determining fertilizer N rates and for comparing EEFs with standard N fertilizers for minimizing N losses. Water quality benefits that derive from such practice changes are being evaluated. Productivity, economic and environmental indicators will validate these strategies for reducing surplus N and produce recommendations for enhanced Best Management Practices.