When farmers Mike and Geoff Strang went looking for a new planter, they weren’t content with buying the latest technology off the shelf. They took their new Kinze 3600Tr planter home and modified it so they can now sow two different corn hybrids at variable rates according to varying soil conditions and yield potential.
The Strang brothers are early adopters of multi-hybrid, variable-rate corn planting, a concept that shows promise in some research but which is so far providing mixed results on their farm and in some research trials.
The Strangs are going into their third planting season with their retrofitted planter and they continue to massage how they use multiple hybrids; about 10 per cent of their acres are getting significantly varied seeding rate and hybrids, meaning an 80 per cent to 20 per cent split. They plant most of their corn acres at a 50-50 rate of the two hybrids in the planter.
Part of their motivation was simply to prove they could create a planter that would vary hybrids, primarily to help increase the pollination window for their corn.
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They can manage projects like this with Mike’s agronomic expertise and Geoff’s background working in automation for Magna, programming laser cutters in plants around the world. They do their own planning and customizing and also write their own guidance scripts.
They also were interested in seeing if they could manage their farm soil types differently.
“We have pretty variable soils,” said Mike. “We have hilly ground, we grow on some high organic-matter dark soil and have some eroded clay knolls. I thought we could take advantage,” of the potential of multi-hybrid planting.
After a couple of years, they can’t point to a significant loss or increase in yield. That’s partly because they are trying other new ideas too, such as using strip till, cover crops, along with planting twin-row corn, in addition to being able to plant variable rates of seed with two different hybrids at the same time.
After sifting through 2016 data, Mike said yields were down about two per cent in the areas where they ran an 80-20 hybrid split compared to areas where they planted half of each hybrid. They are planting 50 per cent of one hybrid and 50 per cent of another in most field conditions, varying population and hybrid up to 80-20 depending on the productivity of the land.
But they’re far from calling it a bust.
What’s the big idea?
The push to try dual hybrids has come from work done by Beck’s Hybrids in the United States where researchers found an increase of 9.6 bushels per acre in 2013 and 2014.
In 2015, with a wetter year powering better results from poorer soils, there wasn’t as much of a difference.
The theory is that lower-productivity soils don’t have the soil structure or the fertility to grow more highly pro- ductive hybrids, planted at high populations, to their full potential.
Those hybrids are called “offensive” or “racehorse” hybrids. In fact, those hybrids may not yield as well on poorer soils, than “defensive” or “workhorse” hybrids, planted at lower populations.
A second hoped-for advantage is the expansion of the pollination window for corn. Two hybrids planted together usually have a 150-200 heat unit difference. That way, if there’s a period of dry weather that delays pollination, there will be pollen shed in the field for a longer period of time, reducing risk of a crop failure due to inadequate pollination.
The five per cent advantage
Aaron Stevenus, a market development agronomist with Pride Seeds has tested multi-hybrid, variable rate plant- ing. He says if you’re going to invest in the upgrades to a planter, as well as in the drives needed to plant multiple hybrids at variable rates, then you need to get five per cent more yield at a minimum.
To pay back the difference in price in the technology over three years, a farmer would need to run a minimum of 355 acres through the planter, assuming an increase of 5.5 bushels per acre. Stevenus assumed corn at $4 per bushel, and was looking at a 12-row planter that could be upgraded, with financing at four per cent interest. There will also likely have to be an increased investment in paying for the scripts to vary the hybrid and population to the management zones in the field. Some farmers, such as the Strangs, can create those scripts themselves, but most do not.
Stevenus tested the concept last growing season on a Pride research farm in Elmira in a trial in co-operation with crop consulting company Veritas. He’s still waiting to get the full results.
However, when Stevenus compared the static check of the same variety in the multi-hybrid trials, he found that the yield results were 5.5 bushels higher for the multi- hybrid, variable rate plot.
“I was pretty excited about it mostly because it was a year when we shouldn’t have had a response. We had a lot of rain and it was not very dry at all,” he said. “The field in general was well-fertilized, and for the soil type, there was decent organic matter.”
The companies took historical yield maps to create management zones of high and lower yielding areas. They created blocks of hybrids within each management zone.
They are going to continue to test the multi-hybrid variable-rate planting in 2018. Stevenus used a John Deere 7000 planter, retrofitted with Precision Planting V-Set Select drives to manage the dual hybrid planting and variable rate seeding.
Greg Stewart, of Maizex, on the other hand, found little overall yield response last year to plots he did that varied hybrids based on management zones. His trials did not include varying seed population, just hybrids.
“Last year, in relatively high-yielding conditions (2017 was a record corn yield year in Ontario), the odds of winning with a defensive hybrid on a poor area, beating an offensive hybrid was fairly slim,” he said.
However, he did see some defensive hybrids that out-performed offensive hybrids on the sharpest sand soils. He noted that areas with the sharpest sand were small so they would have to massively outperform the offensive hybrids on better soils in order to raise whole-field yield above what would be found if only offensive hybrids were planted.
Stewart plans to continue researching multi-hybrid and variable rate planting. He believes seed companies would have selected against defensive hybrids in the past, as they are aimed to be best grown on poor soils — not where most seed companies and yield trials gather their data.
“This has opened up our eyes as a seed company that maybe we should spend a little more time on hybrids that have a niche defensive position.”
Ben Rosser, OMAFRA’s corn specialist says he’s not aware of anyone doing dual-hybrid variable rate plant- ing trials in Ontario academia or at OMAFRA. More work is being done on variable rate planting, without throwing in the further confounding factor of multiple hybrids.
Research is trickling out on multi-hybrid planting. Rachel Stevens, a graduate student at the University of Nebraska-Lincoln, recently presented the results of tri- als from 2016 and 2017. Her work found that the results were mixed, especially because there were a couple of years of above-average moisture. She says more data is needed from drier years.
Linking results with multiple variables can be challenging
Paul Hermans, Eastern Canada’s digital effectiveness manager for DuPont Pioneer has overseen two years of trials in eastern Ontario on variable rate planting.
In 2016, there was a five-bushel response 75 per cent of the time on varying the rate by 4,000 seeds per acre, based on management zones created by multi-year data. In 2017 there was a a 6.5 bushel response, 83 per cent of the time. U.S. trials by DuPont Pioneer in 2012-13 found an eight to 11 bushel response.
If a planter is used for 200 acres, then upgrading to variable rate drives would make sense financially, he said. Most multiple hybrid trials are also combined with variable rate trials, so the question will remain if most of the advantage comes from varying hybrid or rate.
On the farm
Back at the Strang farm, they have found little data available on hybrid selection for multi-hybrid planting, so they’ve been working with their seed dealer to choose the main four hybrids they will plant.
Stevenus says that it can come down to whether hybrid is a fixed-ear or flex-ear hybrid, often the difference between an offensive or defensive hybrid. Fixed ear corn will do better in higher soil fertility areas at higher populations, while a flex ear is better for low populations.
Mike Strang says he’s mostly picking hybrids based on what he’s seen in the field.
The Strangs remain committed to using their multi-hybrid planter going forward.
Mike says that even if multi-hybrid planting doesn’t work, he’s still happy to have the planter based on the extended pollination window two hybrids provide.
Next up for the planter? The Strangs planted 30 acres of twin-row wheat with it last fall, and they’re curious about how multi-hybrid, variable rate soybeans would work.