In brief: Smarter irrigation, more liquidity

A new collaboration between NIWA and Canterbury farmers could see huge gains in irrigation efficiency, with financial savings to match.

A new collaboration between NIWA and Canterbury farmers could see huge gains in irrigation efficiency, with financial savings to match.

Dryland farming depends heavily on irrigation to maintain productivity, but to make best use of it, farmers need to know the moisture content of their soil, when it’s going to rain and how much will fall. They also need to know how much water is available to them at any given time, but, most critically, during dry spells. To that end, NIWA researchers are working with five members of the Waimakariri Irrigation Scheme on a tool that generates customised, site-specific weather forecasts to help them better manage water use.

The new tool measures rainfall, irrigation and soil moisture at each farm, then combines those data with information from the existing Larundel climate station, to offer farmers 2-, 6- and 15-day forecasts. That information is emailed to farmers every day, helping them make a range of management decisions, both daily – such as irrigation scheduling and stock movement – and more strategic, such as planning for water storage. “We’re sending out forecasts to show the farmers how conditions are varying on their farms,” says project leader and NIWA Hydrologist Dr MS Srinivasan, “and how parameters are expected to change over the forecast period of up to 15 days.”

Currently, many farmers don’t have access to that crucial information, says Srinivasan, so will irrigate regardless, rather than risk losing pasture growth. “But if it’s going to rain tomorrow,” he points out, “there may be no need to irrigate today, and that water can be stored or left in the river, so we’re helping farmers optimise their water use and to stay within their allocation limits.”

The tool can also help farmers best schedule fertiliser and manure applications, to avoid having them washed into waterways by unanticipated rain. On the other hand, says Srinivasan, if only a drizzle is forecast, farmers might consider applying urea, as the drizzle can help reduce volatile losses from the fertiliser. “The challenge for us is to find out what information is of most benefit to the farmers,” he says, “and the best methods and times to get that information to them so they can plan effectively.”

On a Ngāi Tahu dairy farm at Eyrewell, “managers are now using realtime information to produce better outcomes,” says Ngai Tahu Farming General Manager Andrew Clayton. “We think it’s great to be partnering with NIWA on a system that’s designed to improve outcomes for the wider environment.”

The initiative is part of the Primary Innovation project, led by AgResearch and funded by the Ministry of Business, Innovation and Employment (MBIE). The project involves scientists from a range of primary sector research organisations, as well as growers, farmers and foresters.

Find out more about the Waimakariri Irrigation Scheme tool