Clearwater County has started experimenting with cover crops, and outlined some of their benefits during its recent West County Ag Tour.
“It’s a great year to talk about cover crops because in order to maintain our moisture in the soil, we are going to need organic matter, which cover crops build. We are going to need cover on the soil to stop the run-off,” said Anne-Marie Bertagnolli, supervisor of the county’s community and agriculture production services.
The county seeded 12 varieties of cover crop on June 20 and over the next few years will be seeing how they affect nutrients, grazing regrowth, and the need for soil amendments. County officials also plan to test different ‘cocktails’ for cover crop blends.
“Historically in agriculture, we’ve become very cognizant of soil physics and soil chemistry,” said Ken Ziegler, a retired provincial beef specialist. “We have not spent a whole lot of time and effort understanding soil microbes and the whole biology that is down there.”
Understanding soil biology is critical to sustainably managing soils, he said.
“What we are doing from a soil cover perspective will invariably enhance soil biology,” said Ziegler. “We know it does, so which crops can we use that will do that well for us, and that we can harvest for our personal benefits?”
Whether land is used for annual crops, pastures, or forestry, there needs to be “a living ecosystem beneath our feet,” said Greg Paranich of Performance Seeds.
“For maximum soil health, you want to have maximum soil cover and crop residues,” he said. “That’s to lower soil surface temperatures. Keep it cooler and a more hospitable environment for all those micro-organisms we want to promote.”
This can be accomplished by planned rotational grazing and integrated pest management, as well as proper selections of plants.
“There’s not just one linear type of solution,” said Paranich. “One hectare of soil contains about 20 pounds of healthy micro-organisms.”
Cover crops also reduce erosion; increase soil structure and organic matter; boost water infiltration and water-holding capacity; and capture nutrients. But the mix of cover crop species matters a lot, he said.
“Some plants have nitrogen fixation, some have nitrogen scavenging. Some cover crops suppress weeds for weed control. Others reduce compaction.”
Other cover crops can be used to create livestock feed, and habitat for wildlife.
“The biggest thing is the increased crop yields year after year,” said Paranich. “We can increase that and actually increase soil health.”
Cover cropping is a system, where plants are grown in non-growth periods between crops to capture sunlight, feed the soil organisms, and sequester carbon.
“You want to capture the nutrients that are farther down and bring them up to the surface, making better use of resources,” said Paranich.
Cover crops include grasses (both warm- and cool-season varieties), brassicas (such as turnips, kales and collards), and legumes — but there’s no simple recipe for which blend to use.
“The neat part about some of the cover crops that are coming to Western Canada is that they are annual legumes,” he said. “They’re annual covers that give you the benefit of a legume without having to have a permanent cover on it.”
The county is starting small in its cover crop trials and is aiming at a two- or three-year rotational plan to begin with.
“If you’re going to do something, let’s do it right, let’s do it well, but maybe not do it over 500 acres,” said Paranich.
Producers may want to have fields of different cover crop mixes, he added.
“Ideally, having a mixture of all of them together can give you a mixture of different benefits and bring it into your soil health. The definition of that is to increase and create as much life below ground as we see above ground.”