Cane-5 . By 2020 , at least 60 per cent of sugarcane areas are managed using best practice herbicide management ( 2016 adoption of these practices is ~ 30-35 per cent ).
Cane-6 . By 2025 , 90 per cent of sugarcane areas are managed using best practice pesticide management .
End of catchment load reduction targets : The Reef 2050 WQIP sets basin specific targets designed to contribute to the long-term outcome that ‘ Good water quality sustains the outstanding universal value of the Great Barrier Reef , builds resilience , improves ecosystem heath , and benefits communities ’. Specific end of catchment load reduction targets are now defined for each of the 35 GBR basins ( Brodie et al ., 2017 ). The targets are based on the need to improve the health and resilience of the GBR and are considered to be ‘ ecologically relevant ’, that is , they are defined to meet certain water quality conditions in the receiving marine environment . Targets were set by using a combination of catchment modelling ( to estimate reductions needed from improved land management practices ) and eReefs marine water modelling ( to calculate how pollutants impact coral reefs and seagrass meadows in the GBR ). Expert scientific advice and technical knowledge complemented the outputs of the modelling . These targets are informed by the increased level of scientific understanding . They are consistent with the framework of targets identified in previous plans but are now drawn from a scientific understanding of the specific water quality needs for each river catchment , based on the parts of the Great Barrier Reef that each river affects .
The definition of basins for this region , in the context of the Lower Burdekin catchment , requires explanation . The Haughton Basin ( as shown in Figure 3.2 ) contains a majority of the sugarcane area within the Lower Burdekin catchment . A portion of the cane growing area is also within the Burdekin Basin , shown ( in faded colours ) on the south of the Burdekin River bank ( Figure 3.2 ; around Home Hill and up-river from Home Hill , and in the Millaroo and Dalbeg areas ). Both the Haughton and Burdekin Basin targets are relevant to this report .
The targets for DIN , fine sediment and particulate nutrients to be achieved by 2025 are shown in Figure 3.3 . The annual average total DIN reduction required from the Haughton and Burdekin Basins combined is 740 tonnes / year . In both basins , it is estimated that 97 per cent of the anthropogenic DIN in the Haughton Basin is from sugarcane areas , and in the Burdekin Basin the estimated anthropogenic contribution from sugarcane areas is 99 per cent ( McCloskey et al ., 2017 ). This is based on a modelled area of 74,640 ha of sugarcane in the Haughton Basin and approximately 22,860 ha of sugarcane in the Burdekin Basin . While more recent evidence suggests that grazing lands may also contribute a portion of the anthropogenic DIN load ( Garzon Garcia et al ., 2018 ), this has not been accounted for in the target calculations as that evidence was not available at the time of their development ( 2016-2017 ). This issue has been identified as a high priority subject for further investigation and improvement ( see Waterhouse et al ., 2018 ).
The BCEG partners have agreed that the DIN targets for the Burdekin and Haughton catchments were confusing due to the delineation / boundaries of the catchments applied to the targets . Two different DIN targets depending on where a farm was situated in the Lower Burdekin is problematic , for planning and communication with growers by creating the perception of inequitable expectations of nitrogen reductions , even though they are being encouraged to adopt similar improvements to farm practices . In an attempt to overcome this , based on the above information , it is reasonable to assume at this time that the target for the annual average anthropogenic DIN reduction from sugarcane the Lower Burdekin catchment by 2025 is in the vicinity of 720 tonnes .
Similar calculations have not been performed for fine sediment and particulate nutrients as they are not being specifically targeted in this Implementation Plan .
For pesticides , the target for all GBR catchments is to protect at least 99 per cent of aquatic species at the end of the catchment . These assessments will be conducted on monitoring data , similar to the process identified in the risk assessment included in Section 3.2.2 .
The 2017 Scientific Consensus Statement ( Chapter 5 , Waterhouse et al ., 2017c ) identified management priorities for the 35 GBR basins and these have been adopted in the Reef 2050 WQIP . The relative spatial priorities are based on the 2017 Scientific Consensus Statement assessment of relative risk ( Chapter 3 , Waterhouse et al ., 2017b ), which assesses the likelihood of ecosystem exposure to anthropogenic pollutants
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