Victorian grower Ray Thornton is addicted to growing corn, and although the crop is more widely known as maize, he is quick to point out that he grows corn, the grain, not maize for silage.

Ray admits he is drawn in by the long, straight rows of seedlings that spring up just five days after sowing and grow to 30 centimetres within two weeks. At three months, the crop is lush, green and almost two metres tall. And the harvest itself is bountiful, with yields of up to 20 tonnes per hectare from some of the best-performing patches on his property near Waaia, north of Shepparton. But he says achieving high average yields across the whole paddock is a challenge.

He has been growing corn for 30 years and has seen average yields increase from 10t/ha to this year’s harvest, which averaged between 17.5 and 18t/ha as a result of new varieties and sowing technology.

While the Thorntons sow more land to cereals than they do to maize, it is maize that has largely driven Ray’s adoption of new technologies, which includes pioneering strip-tilling in Australia along with innovations in seeding and fertiliser applications.

Of their 250ha, they aim to grow up to 100ha of maize most years and sow up to 150 hectares to cereals – mostly wheat, barley and canola. However, they do not double crop.

“Growing maize for grain means the season is about a month too long to double crop, unless you use a grain dryer. If you’re growing it for silage, you harvest earlier and you can get another crop in,” Ray says.

Population priority

In the southern region, maize is generally planted in the last two weeks of October and first two weeks of November, once the soil begins to warm up. Ray’s current crop is Pioneer P0937, a leading variety in the US that comes pre-treated with insecticide to prevent insect damage to corn seedlings.

Plant count is king when it comes to growing corn. I’m planting about 93,000 seeds per hectare, and this year I’ve achieved almost 90,000 plants established. But even at this rate, I’ve lost 3000 possible plants.

“Corn isn’t like canola or wheat, which will tiller out to fill any gaps and increase yield. If you don’t have the population, everything else is pointless.”

Ray highlights soil moisture as critical to germination, and he pre-irrigates five to seven days ahead of planting to give his crop the best chance of success. Any longer and the soil begins to dry out.

Ensuring the seed is bedded into moisture is also the aim of the precision planting technology he uses – it is all about trying to get better plant populations.

This year is the first time he has used his new 360 Wave aftermarket attachment on his planter. It is produced by the US firm 360 Yield  Center.

The planter places the seeds into a V-trench and the 360 Wave effectively closes the trench from the bottom up, rather than from the top down as is the conventional practice. This approach ensures the seeds are surrounded by moist soil from the bottom of the trench, rather than dry soil from the surface.

Fertiliser applications

The planter configuration also allows Ray to add a ‘pop up’ liquid fertiliser boost of 8.8 per cent nitrogen, 11 per cent phosphorus and 1.9 per cent zinc with the seed, designed specifically to help the seed pop up out of the ground. It gives them early nutrition as the plants establish and the roots reach the fertiliser placed prior to planting.

“And this year, emergence has been magnificent,” Ray says. “A much greater percentage of seed has come up, and more evenly. Most of the crop has emerged over 24 hours, rather than being staggered over three to four days.”

The aftermarket attachment that improves Ray Thornton's maize germination success. Photo: Catherine Norwood

Even germination is critical in terms of yield, ensuring all plants get equal access to available fertiliser, rather than being outcompeted by plants that emerge earlier.

Yield potential is set during the first few weeks of establishment. Ray used a Bandit attachment (also from 360 Yield Center) on the seeder to apply more liquid nitrogen (42 per cent nitrogen) in bands along both sides of the seedlings, about 7cm from the plants, at a rate of 120 litres/ha to make sure adequate nitrogen was available during this critical period.

Longer-term fertiliser is provided by the 340kg/h of urea and 300kg of monoammonium phosphate placed in the soil during strip tilling at depths of 250 millimetres and 100mm respectively. There was also an additional topdressing of the crop once it reached chest height, with a combination of urea ammonium nitrate at 100l/ha and liquid urea ammonium sulfate  at 150l/ha applied using a 360 Yield Center Y Dropper, which takes the fertiliser directly to the base of the plants.

This year he applied a combined preventive spray for spider mites and Heliothis caterpillars, also known as native budworms, applied by helicopter.

Straight line approach

The helicopter pilot commented on the evenness of the rows across the Thornton's property; Ray loves a straight line and well-ordered approach.

It is central to the farm efficiency practices he has developed over the past 15 years, after adopting RTK (real-time kinematics) GPS in the mid 2000s.

He redeveloped the farm from its original contour irrigation layout into neatly aligned, laser-levelled bays, complete with an automated high-flow gravity irrigation system he can operate from his phone anywhere in the world.

Ray says RTK GPS and laser levelling have been pivotal in changes to the farm layout, and in the precision planting that has helped to improve farm efficiency and increase yields, particularly for maize.

“Once I got the GPS, I started looking at better ways to do things and that’s when I discovered strip tillage for corn, which was big in the US. I didn’t need to cultivate the whole paddock, just the lines I was going to plant into.”

Tillage and planting techniques refined

He has been refining his tillage and planting techniques ever since, and in 2013 he ordered Australia’s first Kuhn Krause strip tiller from the US to supplement a new John Deere precision planter. The combination significantly simplified his summer cropping operations, saving time and fuel, and preserving soil structure.

Every irrigation bay, check bank and access track is mapped in his GPS software, keeping all his farm equipment running on the right lines. Any deviation incurs a yield penalty, Ray says.

He plants maize on 750mm row spacings, with subsequent maize crops planted into the gap, before moving back to the original line.

“I leave the base of the plants and the root systems in place, and they rot away to help improve the soil quality and soil carbon levels. Because we have such shallow soils in Australia, we have to do a lot of work to build up the subsoil to make it as productive as possible.

“When I go back to the original line, it’s also effectively partly tilled, with gaps in the soil created by the root system of the previous crop.”

If cereals are planted in alternate years, Ray direct-drills three rows of cereal on 250mm spacings between the corn rows.

“Essentially, it’s the GPS technology that lets me continue to farm efficiently,” says Ray, who, at 72 years of age, considers retirement on a regular basis. But each year there’s another crop, another challenge or technology to trial that lures him back into the paddock.