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This project aims to evaluate the potential of VIS/NIR technology for improved nutrient use efficiency in pasture production. The Smart-N system, has been developed by Agri Optics New Zealand Ltd, (NZ Patent Application No 582798) using VIS/NIR sensors. It has the ability to identify urine/dung patches in grazed pasture systems. By using liquid fertiliser it can avoid applying further nutrient to the urine/dung patch. The system is also capable of delivering nitrification inhibitor to only the identified patches.
Nitrogen leaching from dairy pasture is recognised as the number one environmental problem facing our dairy industry, and cow urine patches are the main culprit. The Smart-N system provides the potential to avoid “wasted’ fertiliser inputs to urine patches where no additional response will be gained. It also provides the potential to improve utilisation of expensive nitrification inhibitors by applying them only where needed. By moving to liquid fertiliser there is also the opportunity for improved tactical use of nitrogen, again helping farmers improve their nutrient use efficiency (NUE) while reducing the risk of potential environmental degradation.
It is estimated that dairy farmers may typically use 326 kg/ha of urea at a cost of $202.12/ha. (based on a price of $620/tonne for urea, (Ravensdown price list March 1st 2010), Nitrification inhibitor (Eco – N) application cost to the farmers is estimated at approximately $80/ha. The techniques described in this application could significantly reduce these costs.
All dairy farmers in New Zealand are faced with the issue of nitrate leaching and therefore could all be impacted by this technology. New Zealand’s marketing interests overseas are closely tied to its environmental credentials. This system could be of tremendous assistance to marketing NZ products overseas and assist in bolstering our clean green image through a technological approach that ensures we make more efficient use of our nutrients than our international competitors. As well as achieving industry environmental goals the system would also achieve cost reductions for farmers.
The trial site was set up at Craige Mackenzie’s in late September 2010 with the configuration of new data logging software being completed in early October 2010. On 7 October nitrogen was applied at 4 rates of 0 kg/ha, 600 kg/N, 1200 kg/N, & 1800 kg/N per ha in a replicated trial. VIS/NIR sensing, plate metering and pasture cuts were taken over the next 15 days with the pasture cuts sent for analysis.
A second sampling period was undertaken from 17 November to investigate the length of time that nitrogen could continue to be detected with the VIS/NIR sensors. Analysis of the pastures cuts and comparison to the plate metering and VIS/NIR sensing data is still to be completed.
Analysis of VIS/NIR data has been completed. A presentation was made at the Fertiliser and Lime Research Centre Workshop @ Massey on 10 February 2011 outlining the results of the trial to date.
Verification of the VIS/NIR sensing technology was undertaken in a separate paddock on the same dairy farm. Manual urine and dung patch identification was completed using handheld RTKDGPS accuracy prior to VIS/NIR sensing being completed to the same accuracy level. This was undertaken to verify the ability of the technology to detect the urine and dung patches in a real field type situation.