RRRD055 Progress Updates

November 2012

Science Summary:

-  Equipment is now in place at both diary sites – Gympie and Ravenshoe – to measure nutrient movements, allowing an analysis of nitrogen use efficiency and losses from runoff, phosphorus use and loss, leaching and gaseous transformations.

-  Summer sampling (biomass and soil) is complete at the Gympie and Ravenshoe sites to determine the influence of pasture N content and soil water content on N2O emissions and overall nitrogen utilisation efficiency. At the end of the summer experiment, subplots were dug up and soil sampled; both soil and plant samples were analysed for total C and N and %15N enrichment. Results are also available for N losses via leaching (sampled after rain events) and runoff measurements during summer.

-  The winter rye grass trial commenced at the Gympie site (26/04/2012) and will examine the influence of N fertiliser rates and nitrification inhibitors on biomass production and N losses in runoff, leaching and via gaseous emissions. Four fertiliser treatments plus one control for the 2012 Rye season have been applied and grazing commenced approximately 4 weeks after pasture establishment on 26/06/2012.

-  Due to ryegrass sowing delays, it was decided in May 2012 to establish a second winter trial site in Ravenshoe in a paddock that had been green-struck with ryegrass, , and this second ryegrass site is being monitored over the dry winter season.

Progress Update:

-  All equipment installation and treatments have been completed and winter sampling is complete. Monitoring continues on track, instrumentation is working well and more insight and interpretation of the data will be available after the next summer season of collection.

-  A calculator is under development to determine the gross margin in dollars per hectare between the urea and nitrification inhibitor (ENTEC) treatments. The aim of the cost/benefit analysis is to determine if urea treated with a nitrification inhibitor is an economical alternative to standard urea. The calculator inputs include urea price, ENTEC price, milk price and dry matter to milk conversion rate. Outputs include the gross margin between ENTEC and urea, and the N losses through runoff and leaching from each treatment in terms of both kg/ha and $/ha.

-  QDO has coordinated, advertised and promoted two field days, one at each farm site, to be held on 4th and 6th September 2012. The research objectives, methodology and progress will be explained by the researchers and a fact sheet will be prepared and distributed to farmers attending.

-  In line with the Communication and Extension Strategy, two articles have been published this reporting period: in the Northern Dairyfarmer Magazine, Feb-Mar 2012, and Reef Rescue Water Quality R&D Program Update 4, May 2012.