The dairy industry's year-three report on its commitment to mitigating the environmental impact of farming shows it has achieved six of 13 goals that were set out in 2013 but hasn't yet made a dent in nitrogen loss, underlining the long-term nature of the task of improving waterways.
Nitrogen leaching in the 2015/16 year was a national average 39 kilograms of nitrogen per hectare per year, unchanged from the previous year. Of the 13 regions surveyed using the Overseer computer modelling system, seven actually had an increase in nutrient loss, the worst being Canterbury, which climbed to 64 kg/N/ha/year from a 50 kg N/ha/year rolling average for 2013/14 and 2014/15. Otago has the second-worst deterioration, with an increase to 39 kg N/ha/year from 33 kg N/ha/year.
That particular data has to be taken with a grain of salt because both Canterbury and Otago regions provided more irrigation data for the latest survey, which bumped up their nitrogen loss measure, while a more sophisticated version of Overseer was employed and there were likely changes on individual farms. A total of 9,516 farms nationwide were sampled for the 2015/16 season.
"Nitrogen loss will take longer and in some cases it's going to get worse before it gets better," director of DairyNZ and chair of the Dairy Environment Leadership Group Alister Body told BusinessDesk after a briefing in Wellington for the release of the report. He said the lack of improvement in nitrogen loss reflected changes to Overseer which masked what he believed had been "real progress".
Of the 13 goals, only two of the six goals achieved related to the latest season - riparian guidelines were completed for all regions by May 31, 2016, and for the 2015/16 season, all new dairy conversions complied with environmental standards before milk supply commenced.