By Tony Leggett
Photography by Victoria Rutherford

Optimising production at scale is a challenging goal for farmers, especially on hill country.

But highly accurate aerial imagery is delivering significant breakthroughs in achieving that goal at Ātihau-Whanganui Incorporation’s (AWHI) eight central North Island stations.

AWHI has been involved in the Ravensdown-led Pioneering to Precision Primary Growth Partnership (PGP) project since its inception in 2012.

The project had two aims. First, to improve fertiliser use on hill country through remote sensing of soil nutrient status using hyperspectral camera imagery and more informed soil testing. Secondly, using precision fertiliser application technology developed by Ravensdown to allow variable rate fertiliser applications.

AWHI Chief Executive Andrew Beijeman says slightly more than half their 42,000ha land area has been scanned using a hyperspectral camera mounted on a plane operated by Hyperceptions, a Massey Ventures/Ravensdown Ltd joint venture.

AWHI runs about 75,000 ewes and 4,000 beef breeding cows, plus a significant honey production business built of its resource of manuka, production forestry and a dairy farm.

Once analysed, the images will help guide decisions at AWHI that deliver higher returns and more sustainable farming outcomes.

Andrew says the images collected so far have been hugely beneficial in helping his staff locate hives to optimise honey production and also pinpoint areas of country for management specifically to retain manuka dominance for future honey production.

“What the imagery showed us was we have more manuka than we first thought, and now we know the best spots to put our hives and also the right number of hives to maximise production,” he says.

“It also helped us determine which areas we want to stay in manuka, because manuka is really a colonising plant that is eventually overtaken by other native bush.”

Andrew says the detailed images produced by the hyperspectral camera are data-rich and far superior in accuracy than the typical aerial maps most farmers would be used to working from.

The hyperspectral images provide very accurate effective grazing areas, a significant benefit when operating at AWHI’s scale. They also capture data on slope, aspect and soil nutrient status information that can be fed into the pasture and cropping management plans and fertiliser strategies on each property.

“What we've found is the old aerial maps are just not accurate enough to build a detailed picture of the country ... The hyperspectral imagery is really superior,” he says.

It is a breakthrough for AWHI.

“We just haven’t been able to get anything as accurate as this with other sorts of imagery. You could take hundreds and hundreds of pictures and still not put together something as accurate as the hyperspectral images we’ve got now for AWHI.”

Andrew says being able to apply fertiliser where it is needed and at the correct rate is particularly exciting, especially for hill country farmers.

Rather than relying solely on a small number of soil tests and applying blanket mixes across large areas of a farm, the hyperspectral images coupled with tactical soil testing should significantly improve the ability to apply variable rates of fertiliser based on productivity goals.

“When you've got 21,000ha of pasture to manage; that soil nutrient detail is quite important for optimising the whole place and choosing where we spend money,” Andrew says.

"Now we know how to optimise our fertiliser usage down to each square metre, some areas might get less and others might need more topping up so they grow more grass," he says.

AWHI is expecting to put its first fertiliser plan built off the hyperspectral imagery into action in the first half of 2023.

For more about Hyperceptions see their website.