A five-year collaborative project involving NIWA and a pilot group of Waimakariri farmers has seen a shift from a “just-in-case” approach to irrigation to a “justified” approach, where landowners use real time data and forecasts to make science-based irrigation decisions.

Throughout the NIWA-led Irrigation Insight programme, farmers have been provided with daily data including measured rainfall, soil moisture, soil temperature, drainage, and estimated evaporation as well as two, six and 15-day rainfall and weather forecasts. This data is available in both mobile and desktop systems, in an easy-to-read graphical format.

Soil moisture is measured at eight locations vertically down the soil profile, 10 centimetres apart, which keeps track of the amount of water and the depth the water reaches in the soil to help farmers assess how much water is needed in the coming days. The soil moisture sensors provide an indication of how wet or dry the soil is through the top 30 to 40 centimetres, while the lower levels help to identify occurrence of drainage below the plant root zone.

NIWA hydrologist Dr MS Srinivasan says the study, funded by the Ministry of Business Innovation and Employment (MBIE), has created a close bond between the original five farms involved in the study and his team of researchers, particularly in terms of shared learnings.

“It has shown us how farming and science can work effectively together. We have been adapting our models and information tools as we go, keeping an open mind and making sure farmers’ voices are an equal part of the discussion. Having the practical input is vital for us.”

Over the five years the study has grown to include 20 farms as landowner interest in using the practical data tools has grown.

“Twenty farmers in the study, including the Cust group, have been able to use the information we have gathered both operationally and for the development of their detailed Farm Environment Plans (FEPs) and audits, which makes the data particularly useful for them.

“Although the five-year study will end in September, the group has agreed they will continue to work together as they have learned so much from each other.”

Instead of providing complex data reports, NIWA has developed easily interpreted visual information, and regular weather forecast outlook videos throughout the project. Farmers can log on to the website and see their current and historic soil moisture data, along with a customised local forecast for the next five days, along with longer term predictions in the weather outlook videos.

Dairy farmer Julie Bradshaw says an initial phone call from Environment Canterbury Waimakariri Land Management advisor Anna Veltman led to the formation of the initial group of five farmers located near the Cust Main Drain.

At a recent gathering of the group which also included independent irrigators located in Fernside, Flaxton and Sefton, and primary industry specialists, Julie shared the learnings that both farmers and scientists have gained from working side-by-side over the last five years.

“We’ve had a Cust Water Users’ Group for about 20 years now and this project gave us the opportunity to formalise our approach to data gathering for irrigation. Everyone has been open to sharing their data and we can see that we are all compliant in terms of water takes and usage.

“Gaining the scientific knowledge of what’s happening on our farms has been a real game changer and NIWA have been so supportive. Being able to have comfortable, open discussions about irrigation out here on our farms means a lot to us.”

Julie says having a whole package of data available in an easily digestible format provides the group with a good overview of each irrigation season and enables efficient water allocation, while also helping with compliance requirements.

“We had a lot of restrictions over the last irrigation season but knowing what is ahead and being able to see what’s going on in terms of the soil moisture data and weather means that we have been able to provide everyone with enough water to manage their farms.

“Providing the audit data is simple as everything is in one place. My auditor was really impressed with what we were able to produce. We got an A grade this year for our audit. I was confident in the decisions we had made because we had the facts to back everything up.”

Both NIWA and the farmers involved in the pilot project hope to secure additional funding to extend the programme so they can gain further insights into the production and economic benefits of justified irrigation. The project was also selected as a finalist in the science and research section of the Primary Industry awards.

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