Conservation authority staff planted 60-inch corn near Clinton, Ont., as part of a project seeking to better understand how planting cover crops between corn rows may benefit both the crop and the soil.
Ross Wilson, the water and soils resource coordinator for Ausable Bayfield Conservation, is collaborating with Bill Gibson, the landowner, on the project.
“I had never heard of 60-inch corn until the Innovative Farmers had a talk on it at their conference in February,” Wilson told Farms.com. “We’ve been going from 36-inch corn to 30-, 20- and 15-inch; we’re getting narrower. Why would anybody go the other way?”
But he saw the potential to use the wider spacing to support more light penetration between the corn rows and allow better establishment of cover crops . Wilson reviewed the literature and spoke to farmers in Iowa who had done similar work to help design the project.
“I set up this little trial of six one-acre strips. In each strip, we’re trying something a little different,” Wilson explained.
When it came time to decide which cover crops to plant, project staff were torn between a cover crop that may provide a nitrogen credit to the current corn crop, or a cover crop that may provide more soil health benefits for the subsequent soybean crop. So, project staff are testing both a legume and an annual ryegrass mixture seeded between the corn rows once the corn reaches about the V4 growth stage.
The researchers wanted to establish the extra-wide rows with the same overall field population as 30-inch rows.
“If your planter is capable of planting a higher population, you can just adjust your planter settings. A lot of planters probably don’t go that high,” Wilson said. Instead, Wilson made two passes of the field to create twin rows, 7 inches apart.
Wilson also realized “there could be quite a but of competition between those individual corn plants” with the increased population within the rows. So, he is also testing a reduced population to see if the team can achieve the same or higher yield with less competition.
The researchers want to measure the effects of this planting method on corn yield, soybean yield the following year, and soil parameters.
The team had to select soil health indicators that are responsive in the short-term.
“If we took organic matter before and after, we wouldn’t find any differences,” Wilson explained. “Organic matter values don’t change significantly over a growing season. That’s a years-long exercise.”
A more sensitive soil measurement is infiltration rate. However, that work is labour intensive, he added. So, Wilson will use “an easier approach, which is a compaction tester. It’s actually called a resistance to penetration,” he explained
Less resistance would indicate good soil structure for root growth and penetration, he said.
Farmers across southern Ontario have shown interest in the project.
“I’m surprised at how much interest there really was,” Wilson said. Many producers are experimenting with 60-inch corn, for example, and planting pollinator strips between rows.
Wilson is unsure of what, if any, effects the cover crops will have on next year’s soybean crop.
“That’s what we will learn,” he said.