Data on water use efficiency is critical for understanding water quality influences from irrigation practices , however the level of knowledge is currently limited . Additional data collection as part of future investment is recommended for improving this knowledge . Systems to support this data collection should be established as part of the Implementation Plan .
6.1.5 Additional evidence - fertiliser sales and usage data
As noted in Table 6.1 , whole- of- industry nitrogen use is an important supporting line of evidence for determining adoption rates . To illustrate longer term patterns , the data presented in the Burdekin WQIP 2016 which used published annual Incitec Pivot sales data of nitrogen ( and phosphorus ), is shown here . It is recommended that updated information on fertiliser sales and usage data is sought to support the development of the Implementation Plan .
The data show that fertiliser use gradually declined between 1996 when average nitrogen application rates were in excess of 250 kg N / ha / yr , and recent years where application rates are around 215 - 220 kg N / ha / yr . Note : fertiliser sold in 2011 was used to grow the 2012 crop . Over the ( sales ) period 2011 to 2015 , the average fertiliser sales per year from Incitec Pivot ( produced annually as a useful baseline value ) equated to an average application rate of 215 kg N / yr and varied from 117 kg N / ha in 2013 and 2015 to 209 kg N / ha in 2014 ( AgriTech Solutions , 2015 ). This sort of information is used to support the adoption data presented above .
The aggregation of fertiliser usage data in the BRIA and Delta regions is also useful to consider . The regulated Six Easy Steps fertiliser application rate in the Burdekin Region ( under the Great Barrier Reef Protection Amendment Act 2009 ) is 170 kg N / ha / yr in plant-cane and 210 kg N / ha / yr in ratoon-cane , however , growers had the ability to apply for an exemption to apply 240 kg N / ha / yr until further trials were completed through the RP20 Burdekin Nitrogen Trials project ( 2011-2016 ) led by SRA and funded by the Queensland Government ( SRA , 2017b ). While the project is ongoing , it has sufficiently demonstrated that nitrogen rates in line with reef regulations and the industry standard , Six Easy Steps , are sufficient to meet the nitrogen requirements of Burdekin sugarcane crops . In addition , the mid-term economic evaluation showed that farm profitability was improved with this level of nitrogen application , as it reduced input costs and maintained sugar production . In March 2017 , the Queensland Government released the Enhancing regulations to ensure clean water for a healthy Great Barrier Reef and a prosperous Queensland discussion paper for feedback . The paper outlined a number of high level proposals to enhance the existing reef protection regulations to reduce nutrient and sediment pollution across key industries in GBR catchments . Information sessions were also held during the consultation period , which closed in mid-May 2017 . A second round of consultation has recently been completed , and the regulations are expected to be in place in 2019 .
Analysis of Paddock to Reef program surveys of fertiliser application rates for plant and ratoon crops in 2015 ( undertaken as part of the prioritisation exercise for the Burdekin WQIP 2016 , see Waterhouse et al ., 2016 ) illustrated how nitrogen surplus could be calculated . At this time , the data showed that 92 per cent of respondents in the BRIA and 82 per cent of respondents in the Delta were applying beyond 170 kg N / ha / yr in plant-cane . In ratoon-cane , 71 per cent of respondents in the BRIA and 62 percent of respondents in the Delta were applying more than 210 kg N / ha / yr . Figure 6.1 shows this data represented as the nitrogen rate applied above ( i . e . in excess of ) the Six Easy Steps guideline , and the average value of nitrogen savings per hectare of application rates were as per Six Easy Steps . When assessed over a full crop cycle and extrapolated to the whole region , the nitrogen ‘ surplus ’ equates to approximately 1,760 tonnes per year in the BRIA and 360 tonnes per year in the Delta , with potential savings of up to $ 187 per hectare in plantcane and $ 252 per hectare in ratoon-cane .
This data , along with fertiliser sales records point to significant application of nitrogenous fertiliser beyond industry recommended Six Easy Steps guidelines in the BRIA and the Delta regions as at 2015 . Trials and crop modelling indicate there is significant scope for environmental and economic benefits from reduction in fertiliser application rates . Based on the current adoption rates presented in 6.1.2 , it is likely that the current estimates of potential nitrogen surplus would be a similar order of magnitude .
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