POTENTIAL PRODUCTION AND ENVIRONMENTAL BENEFITS FROM CONTROLLED RELEASE FERTILISERS-LESSONS FROM A SIMULATION ANALYSIS

CONTROLLED RELEASE FERTILISERS (CRFs) are promoted as a means to reduce nitrogen (N) losses and allow lower N application rates in sugarcane systems. The idea behind controlled release fertilisers is that a slow release of N synchronised with crop N uptake will keep the levels of mobile soil nitrate low. This will reduce the risk of N loss by denitrification, runoff or leaching and therefore make more N available to the crop. Experimental trials have in some cases demonstrated the effectiveness of controlled release fertilisers, but questions remain around the magnitude and consistency of benefits. Using simulation analysis we quantify the production and environmental benefits for a case study in Tully, Queensland. There is a role for controlled release fertilisers to reduce nitrogen loss, improve nitrogen use efficiency and sometimes increase yield, but results are seasonally variable and depending on conditions as well as fertiliser release characteristics. Successful implementation will likely require decision support.