Otago farmers increasingly adopting 'fertigation'

Pamu's newly installed fertigation system will help trial whether using fertigation can reduce nutrient losses. Photo / Supplied

Central Otago farmer Andrew Paterson is among those adopting "fertigation" - a new way of applying fertiliser that is cited as having environmental benefits.

The technique allowed irrigators to be used to apply liquid fertiliser or liquid soluble fertiliser in small quantities at the same time as water.

Most fertiliser presently used in New Zealand was solid and applied through ground spreading or aerial top dressing.

Internationally, fertigation was increasingly being adopted as good environmental practice, Irrigation New Zealand's (INZ) outgoing chief executive Andrew Curtis said.

In September, Irrigation NZ organised a study tour to Nebraska, where farmers are encouraged by authorities to use fertigation as a tool to help reduce fertiliser use and reduce nitrogen leaching, while also saving costs by reducing the labour involved in applying fertiliser.

The group, which included farmers, irrigation designers, environmental consultants and irrigation scheme representatives, was excited about the opportunities to adopt fertigation in New Zealand.

A new guide has been released which would assist both farmers and the irrigation industry to adopt the practice.

Pamu (Landcorp) was also working with Irrigation NZ to trial the use of fertigation over two irrigation seasons to see whether the practice resulted in less nitrogen leaching, and had other benefits on farm through cost or labour savings.

The trial focused on reducing Pamu farm's nitrogen consumption and loss to the environment on irrigated Canterbury dairy farms.

Ballance Agri-Nutrients was a partner in the planned trial which was being supported through a grant from the Sustainable Farming Fund.

A small number of irrigators were already using fertigation successfully in New Zealand and, if the trial showed it to be a better environmental practice, as well as practical to implement on farms, INZ would like to see it more widely adopted, Curtis said.

Among the farmers embracing the practice were Mr Paterson, who farms Matakanui Station near Omakau, with his wife, Tracy.

He saw applying fertiliser via pivots as a much more convenient option on his sheep and beef property, allowing him to save time through not having to spread it through trucks, while allowing him to use the fertiliser more efficiently.

"With fertigation, you're not putting on large amounts of fertiliser in one hit. You're putting on smaller doses mixed with a little water, so you're not losing fertiliser into the ground. We've had a tremendous response from the clover and grass."

Curtis said fertigation could also be used to apply products like seaweed and selenium to crops and pastures.