Craige Mackenzie, Canterbury

Mid-Canterbury arable and dairy farmer Craige Mackenzie's philosophy is right input, right quantity, right place, right time—which makes sense for his business and for the land, waterways and climate. Conditions often aren't in his favour, but precision technology is helping to even the odds.

Learn how Craige Mackenzie uses precision technology to help reduce greenhouse gas emissions on his mid-Canterbury farm.

Transcript

Duration: 4:48

CRAIGE MACKENZIE
Mum and Dad bought this property, 50 years next June. So, I've been here most of my life.

When we came it was a very run down place that needed a lot of attention.

The guy that lived here before used to do a lot of hunting with hares and under the trees there used to be a lot of gin bottles and other things.

It was a huge change from where we are today.

Mostly we're only limited by our imagination.

Our drivers as a family have been to do the best with what we've had.

We've got lots of variability on this farm. If you drive up the Methven highway and you'll see some nice soils.

We've got a little bit of that, but we've also got a lot of light soils.

So we had to manage things a lot more carefully than some of the guys with really good soils. It's not very forgiving here at all.

We did a yield map out of a combine harvester, and ran it through a computer to make a profit map.

And we were losing money in certain areas, I'm of Scottish heritage and that didn't sit well, so we needed to fix that.

When you've got lots of variability in the soil you've got different potential in different areas.

We know that some areas will grow 8 tonne to the hectare, some 12, some 14 and some 16 of a wheat crop.

And that's great, but actually you only need to put on the appropriate amount of fertiliser to grow the 8 tonne or the 12 or whatever.

So, by mapping the soil, knowing where the variability is and looking at what the potential is.

We've said, over there we put on 150kg and there we put on 200kg and there 250kg, so we absolutely get the right amount of input as a base fertiliser.

Then we're also looking at the variability in the field through the growing season.

With satellite imagery and we've got our own sensors and drones, to look at what we can do in different areas.

Weather forecasting is hugely important for us, we've got 35 zones that measure soil moisture and we've got irrigators that put different amounts of water in different places

By getting really accurate weather forecasts would mean that we can choose to apply irrigation or not.

It's hugely important, hugely valuable for us as a decision making tool.

For most of that technology we will get a return on investment within 12 months, if not 24.

So that's a pretty good investment. If you buy a new tractor it's no different to the last one.

It might look good, it might be comfortable, it might be efficient but where's the real benefit?

Precision agriculture is about doing the right thing in the right place at the right time and in the right way.

And only putting on the right amount of inputs. There's a whole raft of different ways to look at that.

But for me it doesn't matter whether it's economic or environmental sustainability, reducing our carbon footprint is another way to look at it.

But all of them have the same outcome, so whichever way you look at it you'll end up using the same technology.

We've got a dairy operation next door on 330 hectares, we're milking around 1000 cows.

It gives us some flexibility, we did it for diversity. That soil type was lighter - more in keeping with pastoral farming than straight cropping.

The techniques that we use here equally fit on the dairy farm.

This isn't about arable, it's not about dairy, it's not about sheep and beef, horticulture, viticulture. It fits across all sectors.

We still need to make the decisions about what we put on, so it's not about artificial intelligence.

It's actually about farmer intelligence.

We're trying to make the most appropriate decision to grow the crop in the most appropriate way.

To give us the best financial outcome and the best environmental sustainability.

About the farm

Craige and Roz Mackenzie farm Greenvale Pastures on the Canterbury Plains near Methven.

Greenvale is a 200-hectare intensive, irrigated cropping farm growing high value seed crops (including wheat, fescue, ryegrass, hybrid carrots, pak choi, radish and chicory) and cereals – with an enduring emphasis on environmentally sustainable farming practices.

SIDE NOTE: 65% of the world’s carrot seed is grown in the Canterbury area, and 35% of the world’s radish seed.

The farm’s location, one-third of the way between the mountains and the sea, makes for some interesting climatic challenges with both alpine and coastal effects during the year.

On average, Greenvale gets 900 mm rainfall per year on a 50-year average, although in 2021 it received 1670 mm. However, the water-holding capacity in the different soil types on the property ranges from 60mm to 200mm in the top 60cm. In addition, the farm can get significant west to nor-west winds, although this is contrasted with the ability to receive up to a metre of snow during some winters.

To help combat the climatic challenges and stabilise production conditions for their crops, irrigation was introduced to the farm in the 1980s. Craige has since pioneered a precision irrigation system that has seen the property divided into 35 individually managed zones. Soil variability is mapped via electromagnetic sensors and the soil survey data determines where soil moisture probes are placed in each zone. These then feed information back to Craige’s laptop in real time along with rainfall and evapotranspiration data to work out where water is and, importantly, isn’t needed. He consults high-resolution weather forecasts to see if nature is likely to deliver that water or if irrigation is needed.

Through the soil mapping and testing process, Craige also discovered that potential yields varied significantly across the farm. He realised that he was overdoing the inputs in some areas, which wasn’t good for his bottom line or the environment. Now, data from soil maps, spatial soil sampling, yield analyses and nitrogen scanners help him calculate exactly how much fertiliser is required.

GPS-driven variable rate irrigators, sprayers and fertiliser applicators are then put to work, delivering precise doses of water and fertiliser in exact locations across the farm.

Craige also uses this wealth of data to carefully plan his crop rotations, avoiding the need for cover crops and ensuring no land is left fallow. This helps further reduce the amount of nitrogen used, along with other inputs. It also staggers how much water might be required for any given crop and helps improve soil quality and health.

For Craige, while the upfront investment wasn’t cheap, he’s seeing returns within 12-24 months and the longer-term payoffs have been significant too.

Environmental focus

The benefits of Craige’s precision agriculture approach are not just evident in his increased production and productivity – the environment has been a winner too. Since 2016, the Mackenzies have reduced their water use by 30-40% and their fertiliser use by 30%.

These efforts have been underpinned by a farm environment plan, required as part of the Ashburton-Lyndhurst Irrigation Scheme that Craige is a member of.

His system is now capable of ensuring that water does not go past the root zone, significantly limiting nitrate and phosphate leaching.  

“For us, it’s about using our resources as wisely as we can and having the lightest footprint possible on the environment,” says Craige. “We believe in protecting and carefully managing this land for future generations.” 

But just what impact have Craige’s actions had on the climate?

Craige's greenhouse gas numbers

Craige’s use of precision agriculture means he is already able to capture an array of data for his farm. Getting his greenhouse gas numbers together was relatively straightforward – completed via Overseer.

Overseer is just one of a number of tools available for farmers to find out their greenhouse gas numbers. You can read more about them on our Know Your Numbers page.

Greenvale Pastures 2019 2020 % change
Effective area (ha) 197.4 197.4 0
Total methane (tonnes CO2e/ha) 1,080 1,044 -3.3%
Total nitrous oxide (tonnes CO2e/ha) 2,149 1,912 -11%
Total carbon dioxide from nitrogen fertiliser (kg/ha) 994 1,011 1.7%
Total biological GHG emissions (tonnes CO2e/ha) 4.2 4.0 -6.1%
       
N surplus 185 152 -17.8%
Methane (kg/ha) 43.2 41.8 -3.3%

Year on year, precision agriculture enables Craige to continue making efficiency gains and reducing key inputs like nitrogen fertiliser. In turn, this has a positive effect for the climate with 11% less nitrous oxide emissions between 2019 and 2020 and nearly 18% less nitrogen surplus.

On-farm actions

Craige’s dual focus on innovation and sustainability has led to positive outcomes for the climate. The main way he has reduced his emissions is by managing his nitrogen use via precision agriculture:

  • Matching inputs to crop requirements
  • Variable rate application
  • Using urease inhibitors
  • Soil mapping and regular testing
  • Crop rotation
  • GPS mapping
  • Using crop sensors and satellite imagery

For more on this and other ways to reduce agricultural greenhouse gas emissions, see our Current Actions page.

Know your numbers and have a plan

By now, all farmers and growers must have a record of their annual on-farm greenhouse gas emissions (methane and nitrous oxide). By the end of 2024, they'll also need to have a written plan in place to manage them. These requirements are part of the He Waka Eke Noa partnership and are intended to help get farmers ready for agricultural greenhouse gas emissions to be priced from 2025. To find out more on how to do this, see our Know Your Numbers page.