Cover crops continue to be one of the most discussed topics in Ontario crop farming.
However the discussion has moved beyond the existence of the soil-health-building practice, to the fine details of how to manage such a complex biological system.
There were several sessions at the recent Southwest Ag Conference (SWAC) in Ridgetown dedicated to cover crops that brought together the innovators of the practice. This year discussion has moved to interseeding between the rows of living crops, especially corn and planting into living cover crops, called ‘planting green.’
On Gerard Grubb’s farm near Mildmay, Ont., he is interseeding ryegrass with a Valmar air system that moves the seed to booms from which drops place the seed between the corn rows or on wheat. The system allows them to do it quickly and later in the season than trying to frost seed a cover crop.
Grubb told one of the sessions at SWAC that he doesn’t want to ever disturb the soil while planting a cover crop, as it will then result in more weeds. As one of the goals of planting a cover crop is weed suppression, he is determined that he will continue to place his cover crop seed on top of the soil.
Other cover crop innovators, however, are focusing on getting seed into the soil with the soil-to-seed contact that results in better germination.
It was a request from a farmer that led Shawn Redick of Delta Power Equipment to build a new planting tool.
“Growers wanted a solution to put on 28 per cent (of their nitrogen) and plant cover crops at the same time. They found broadcast was not great. You need that seed-to-soil contact,” he says.
He took a Great Plains NutriPro 2330LL toolbar and added in a Valmar applicator for the seed. That meant there was no room for a liquid fertilizer container on the toolbar, so they pulled a Montag 1,200-gallon tank behind on a cart for the 28 per cent. Tubes for the seed and the fertilizer were run to the coulters. Both of the application units had variable-rate drives, so a Trimble field application control was used.
Delta then used the unit across several farms in different soil types. Redick says he had much better results with the counter-applied seed versus broadcast. The trials used a 60 per cent annual ryegrass and 40 per cent red clover mix.
Jaclyn Clark, a master’s student at the University of Guelph, is conducting research on interseeding cover crops and the resulting corn yield. Her trials drilled and broadcast seed into corn at V4 to V6 stages of growth using different mixes of red clover and annual ryegrass. After a season and a half, her trials so far show that corn yields are not impacted by a live cover crop. She has also found that cover crop biomass is significantly greater when the corn is harvested as silage versus grain corn.
She has found that drilled seed survives better than broadcast.
The debate over drilled seed is one typical of the cover crop discussion. Different farmers have variable results with the same process, seed and technology.
Cover crops aren’t for the faint of heart, but there isn’t much doubt that more farmers are using cover crops, and despite some disasters this past year, they are continuing to experiment more each year. That’s especially true with cover crop innovators.
Four of those innovators also spoke at SWAC to an overcrowded room of farmers.
Laurent Van Arkel of Dresden had a challenging cover crop year like many farmers. He planted soybeans in a green cover crop which resulted in a five-bushel-per-acre yield hit compared to soybeans planted into a killed cover crop. He was happy with how the crop planted, but the thickness of the cover crop was too much competition.
In a way Van Arkel and others speaking about cover crops at SWAC have had too much success as many said they wanted to reduce cover crop seeding rates, as some of their stands, especially ryegrass, were too thick to plant into or kill easily.
Rob Luymes also tried to interseed a cover crop in corn. They harvested the corn for silage, then watched the cover crop grow well. The next spring they planted into the green cover, and the planting failed.
Luymes said the rows closed well, but when the hot and dry weather arrived shortly after, the seed trenches opened up and the stand was knocked down to 40,000 plants per acre.
Luymes and other speakers like Dan Petker and Kerry Lunn all agree that more research and understanding is needed to figure out how to better close the soil over the seed.
Most have used the standard rubber packer wheels that come with planters, but they are looking at alternatives that will do more to crumble the soil over the seed.
Petker says they couldn’t get enough down pressure when planting into a green crop to get rows to close.
Early cover crop adopters each have their own reasons for using cover crops. For Van Arkel it’s keeping living roots in his soil, for Petker, it’s to get the advantages of wheat in a rotation each year, versus every three. For Lunn, it was to build moisture retention ability and for Grubb, it was to increase soil tilth.
“We are farming for the future,” says Petker. “Cover crops are part of our future and we just have to do it now.”