From a “reset” of their fertiliser program to the introduction of SwarmBots, John and Mark Flannagan are focusing on efficiencies to improve farm viability in increasingly variable seasonal conditions

After more than two decades of farm mapping, Western Australian grain growers John and Mark Flannagan are resetting their fertiliser program to more accurately target their best-performing ground and boost yields.

The Flannagans farm more than 40,000 hectares of owned and leased land in WA’s northern wheatbelt. They grow mostly wheat-on-wheat, with canola and lupins in the rotation mix as seasonal conditions allow.

As early adopters of variable-rate technology, the brothers have a useful history of soil types, soil moisture, fertiliser applications and crop yields to refer to. These are already used in paddock and crop selection and will also play an important role in what the Flannagans refer to as their “nutrition reset”.

After years of variable-rate fertiliser applications, they have decided to apply an even application of nitrogen and phosphate to their paddocks in the coming two seasons. John says this should show more clearly which areas have the potential to produce consistently higher yields and will allow them to “reset” their variable-rate maps.

Intuitively, John says, they have a fair idea of how paddocks perform and which areas of the property may benefit from targeted fertiliser. However, the new mapping will give them more comprehensive information to build up their data bank.

Lime program

Previous generations have run a wheat and sheep enterprise, a traditional mix for the region.

However, in the 1990s, John and Mark – the third generation – decided to focus their energy on crops and a liming program has been underway since then. They annually apply the recommended rate of one to two tonnes per hectare to improve soil pH.

“We’ve got a wide range of soil types that even over a 200ha paddock can produce significant yield differences,” John says.

“Some of the soils have a fairly decent pH. Others have required lime to bring it up to a level better suited to wheat. For some paddocks, the improvements in yield have been significant with the application of lime, but it can be season dependent.”

The Flannagans recently hosted a liming trial for the Department of Primary Industries and Regional Development (DPIRD), WA.

The trial looked at where lime applications in low-rainfall zones improved yield.

It found that the greatest yield benefit occurred in years of lower growing-season rainfall. That is, where there was stored subsoil moisture from either a large summer rainfall event or following a fallow year.

It was clear, John says, that the application of lime on those paddocks with soil moisture definitely improved the yields.

Farm manager Cameron Jenkin (left) works closely with grain grower and enterprise owner John Flannagan to use data collected over many years to refine variable-rate maps. Photo: Evan Collis

Fallow for soil moisture

The Flannagans’ rainfall average is 250 to 300 millimetres a year, and there are years when it is significantly less.

Where soil moisture allows it, wheat-on-wheat will be planted. However, a wheat and fallow rotation is mostly used to retain soil moisture and reduce weed burden. Lupins or canola may be considered if there has been good rain in the lead-up to sowing.

John says for every 10 years, there will be four years when rainfall is not sufficient for a viable crop. But if left to fallow, a profitable wheat crop can be grown the following year.

“Compare that (fallow option) to wheat after canola on 130mm and that rotation would send us backwards,” he says.

He says yields are lean in years with less than 200mm of rain, so holding the soil moisture is important. “Fallow can lift a couple of those poorer seasons into a good season and keep you going forward.”

Fallow years also lend themselves to cleaning paddocks of weeds.

Fallow spraying is usually done in August for the cooler climate weeds, then again through November to December for the summer weeds.

Clean-up spraying will continue as needed. Typical weeds include roly-poly tumbleweeds, tar vine, button grass and melons. The fallow also allows chemical rotation to minimise the risk of herbicide resistance or crop damage.

Fallows in years of low rainfall provide a vital moisture store for following crops and allow for weed clean-up. Photo: Evan Collis

Spray and repeat – autonomously

The purchase of SwarmBots has made a significant difference to the operation.

As autonomous vehicles, the SwarmBots tow boom sprays up to 24 metres wide. The Flannagans now use SwarmBots to tow WEED-IT optical spot sprayers.

In 2024, John and Mark purchased ‘Alfie’ the SwarmBot, named after their father, and more recently ‘Ailsa’, named after their mother. In 2025, Alfie and Ailsa will be joined by a third SwarmBot, Annie, named after their grandmother.

“The biggest problem with human-operated tractors is boredom, which leads to errors,” John says. “The risk of hitting a fence or an obstacle in the paddock is far greater with a human operator, which in turn can lead to broken equipment and lost time for repairs.

“With the SwarmBot, it will use the mapping to avoid those obstacles and just keep going. We get an alert if there is a problem, but otherwise it only returns to the shed when it needs fuel.

“The other benefit is that it can operate at night, when the efficacy of the chemicals is greater due to the lower Delta T. (Delta T is used to indicate evaporation rate and droplet survival and is important for spraying operations.) No one likes to be working at 3am, but a SwarmBot can.”

Inputs continue to be a major cost point for John and Mark, but with improvements in data collection greater efficiencies are being found.

The introduction of soil mapping, variable-rate technology and the SwarmBots has made the operation run more smoothly and more cost-effectively, taking advantage of the better seasons and staying ahead in the marginal rainfall years. SwarmFarm Robotics – the company behind the SwarmBots – was a GRDC GrainInnovate investment (see GroundCover^TM story – Agtech momentum building on startups investment). This portfolio has been found to have a profound impact on the Australian grains industry.