Condobolin Precision Ag day: Multi-hybrid planter solves soil variability issue

Having different types of soil in one paddock means planting the same crop across the entire field could result in yield losses where the soil type does not match the requirements of the crop sown.

However, a producer in New South Wales, who faced this problem on his own farm, has come up with an innovative solution.

David McGavin grows sorghum on his 390ha property at Premer, on the Liverpool Plains, using a multi-hybrid planter to sow two varieties across the one paddock to match the varying soil conditions.

Similar to a standard cotton planter, the multi-hybrid planter has two side-by-side vSet meters sharing a common seed tube.

The electric drive meters are fed by twin mini hoppers and a central fill tank, imported from the US and installed on top of the tool bar.

The meters can achieve 99 per cent singulation, giving the ability to do full variable rate.

"Internally, there are two disks with one turning off when required to plant a particular variety so there are no gaps in the paddock," McGavin says.

"We can simultaneously turn one variety on and the other off, plus individual rows, depending on the mapping software. Because the meters are electrically driven, that gives us the ability to vary the [planting] speed at 200 times a second."

Data tells all

A bank of yield data has revealed much variability in crop yields across the family’s farm in the past five years.

A decision to trial an improved metering system on their traditional planter led the family on a research journey of precision seeding equipment.

David and his wife Lauren established Precision Seeding Solutions, and now regularly test new precision agricultural technology on their own farm.

Their mapping had revealed variability in soil types leading to decreased crop yield.

"We have been collecting yield data for close to 10 years but have only seriously looked at trends between sorghum and wheat yields in the last five years," McGavin says.

"I didn't want to base my varietal change on harvest data only. With the multi-hybrid hoppers, we needed a way to work out what we were going to base our two variety changes on."

The McGavins invested in a U-Series Veris machine for mapping soil electrical conductivity and organic matter.

David McGavin initially considered variable rate seeding as the option.

"Sometimes if we put in a low plant population of a particular sorghum variety, it can tiller hard, doing us a disservice," he says.

"In the past, one variety grew a huge amount of biomass and we had to bale it for silage. Across the 122ha paddock, variability in yield that year ranged from 2.5 to 7.5m/ha.

"We wanted to know why we were only getting half the yield in one part of the paddock compared to another section 100m away, so we decided to go down the track of putting two different varieties in."

Put to the test

The multi-hybrid planter was used to sow varieties of sorghum – MR-Taurus and MR-Scorpio – last October.

McGavin says Scorpio had produced a lot of biomass in the past.

"By using the multi-hybrid, we could identify the best soil types on the farm, map those areas, and only plant Scorpio in those areas," he says.

"Scorpio is almost an irrigated variety and needs a deep soil with lots of moisture."

On average, Scorpio yielded 7.1t/ha while Taurus yielded 6.3t/ha to give an overall average of 6.7t/ha.

"The multi-hybrid cost me about $1000 extra per row above a standard system to total $19,000 [across 19 rows]," McGavin says.

"The yield increase equated to an additional $28,800 across our whole property – I didn't think it would pay back in one year but it has.

"This is not based on proving whether the variety made a difference but having the ability to change or do something different."

McGavin says the multi-hybrid planter allowed real-time data to be viewed on an iPad at planting.

"It's a good time to be in agriculture – the new technology has a payback but it's great there are people out there developing products," he says.

"When my father goes to the paddock and doesn't know how to turn the GPS system on, he can use the multi-hybrid planter as all he has to do is flick a switch."

According to McGavin, the central fill system was "high maintenance" with larger seeds, such as chickpeas, but growers were seeing yield, germination and ripening benefits.

The two sorghum varieties were harvested simultaneously and blended for sale on the stock feed market.

"During harvest, the yield monitor on the header told us what varieties were in and we can then overlay those maps," he says.

"The maximum difference in timing of harvest between the two varieties can be up to nine days – ours was six to seven days.

"The timing of the two crops didn't affect us with weed control."

Emerging technology

Speaking at the Central West Farming Systems precision agriculture seminar in late June, McGavin outlined new digital agricultural platforms on the horizon.

These include SmartFirmer, a seed firmer with unprecedented sensing capability.

He says infrared lights are used to measure the colour change in soil.

"It will give the farmer the ability to collect his own data although it will still need to be processed by a third party," he says.

"The seed firmer can be put on every row or one per planter if less high-definition mapping is required. It is also giving us a map of stubble residue and moisture in the trench."

McGavin says mapping of soil moisture in-furrow would allow growers to change planting depth as soil conditions changed.

He says the seed firmer gave on-the-go control of planting population or hybrid based on organic matter measurement.