SPECIAL REPORT • FERTIGATION
Johan Joubert and Steve Breneger – the purpose-built tank and trailer unit with specialist fertigation pump and control system can be moved easily from pivot to pivot.
FERTILISING with irrigation Fertigation - applying fertiliser through irrigation - has allowed Pamu Farms to make significant cuts to nitrogen use on a Canterbury farm. Anne Lee reports.
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pplying nitrogen through fertigation has allowed Pāmu Farms to slash its nitrogen use without limiting milk production and studies are underway to understand how the application system could be affecting feed quantity, quality and potential nitrate losses. Pāmu Farms has been using fertigation – applying fertiliser though irrigation – on its Waimakariri Farm in Canterbury since the 2018-19 season. It saw a 42% cut in nitrogen use on historic levels in the first year and 25% in the second giving an average 36% reduction on typical use so far. Irrigation New Zealand technical manager Steve Breneger designed the system installed on the farm and is the technical lead in a wider project that includes Pamu’s onfarm experience in tandem with a scientific study at Lincoln University into the effects of fertigation on
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pastoral management and environmental loss. Ballance Agri-Nutrients, Lincoln University, Irrigation New Zealand, Fertigation Systems, Molloy Agriculture and the Sustainable Farming Fund are all supporting the project. “The headline numbers we’ve seen in terms of nitrogen reduction at Pāmu are very positive but we can’t go out and say, based on one farm’s experience over two seasons that all farms are going to achieve the same outcomes,” Steve says. “Fertigation has been used for decades overseas and in horticulture here but there’s really no research on pastoral farming. “That’s why this study is important – having the science going on along with the practical implementation. “The science is informing what Pāmu is doing but at the same time the questions they have get fed back for the science to answer.
“It’s important that we keep looking for those answers. We’ve got big reduction targets to meet here in Canterbury especially and the 190kg (nitrogen/ hectare) limit we’ve just seen imposed makes this even more timely.” Fertigation has been attempted in Canterbury before but Breneger says the key to setting up a successful system comes at the front end with design. “You have to be very clear about what you’re trying to achieve, what risks or problems you’re aiming to solve and the level of hands on management you want.” “In Pāmu’s case they were looking for a 20% reduction in nitrogen application over five years and they wanted it to be able to pay for itself over that period. “They wanted to use existing infrastructure as much as possible and where new infrastructure was needed, they wanted to be able to move it out if things didn’t work out.
Dairy Exporter | www.nzfarmlife.co.nz | July 2020
