DairyNZ programme helps Canterbury dairy farmers achieve nitrogen targets
Results from DairyNZ’s five-year Selwyn and Hinds programme show significant change has occurred to help reduce farm nitrogen (N) losses and improve water quality outcomes.
The programme, which started in 2018 and is coming to an end, saw DairyNZ partner with 40 dairy farmers in the two Canterbury catchments. DairyNZ analysis of combined Selwyn and Hinds partner farm data shows there has been a 44 percent reduction in N loss from the farms’ baseline time to the latest year-end.
Farmers in the Hinds catchment are on track to meet the significant N loss target set by Environment Canterbury, with the first milestone being a 15 percent reduction by 2025. In Selwyn, dairy farmers needed to achieve a 30 percent reduction by 2022. Overseer information shows N loss reductions of 29 percent from the 2017/18 season to 2021/22, and a report released last week shows a continued downward trend in mean N loss per hectare from dairy farms across Canterbury – a 27.5 per cent decrease over five years to 2021-22.
The Selwyn and Hinds programme aimed to support dairy farmers in these catchments to meet Environment Canterbury and central government N loss reduction targets, while optimising profit and resilience. DairyNZ general manager for sustainable dairy, Dr David Burger, says the amount of change in both catchments is encouraging and shows the sector is moving in the right direction.
“Dairy farmers across Canterbury are improving effluent and irrigation management, reducing fertiliser use and increasing their focus on overall efficiency of farm systems, which helps reduce nitrogen being lost into groundwater.”
For example, Hinds farmers Phill and Jos Everest, who farm with their son Paul and his partner Sarah, have made a range of on-farm changes to meet N loss regulations. This includes reducing nitrogen fertiliser use by 35 percent – ahead of national and regional regulatory requirements – and developing an annual N application plan to identify monthly application rates needed to meet the new targets.
Thanks to these on-farm changes, Phill, Jos, Paul and Sarah have already met their 2030 target to reduce N losses by 25 percent.
Throughout the Selwyn and Hinds programme, different options for reducing N loss were trialled across individual farms, depending on the needs of specific farm systems. The results and learnings were shared with other local farmers through field days and events.
“The programme has supported dairy farmers to reduce N losses by implementing solutions that work at a farm level, complementing the positive work already being done by farmers and rural professionals,” Dr Burger says.
“It has also presented good opportunities for dairy farmers to share ideas and work with scientists and sector experts. Farmers have been using the information available to them to implement the best options for their farms.”
Examples of effective options include catch crops, which are grown to contain excess nitrogen in soils that may otherwise be lost through leaching, and plantain, a low-cost, high-impact mitigation many farmers have incorporated.
The Selwyn and Hinds programme was an extension of previous DairyNZ-led N loss farm systems research, such as Pastoral 21 and Forage for Reduce N leaching. Many partner farms implemented several of the options identified by this previous research.
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