An ancient practice involving the use of cover crops is being brought up with farmers across Canada.
Callum Morrison is a second year PhD student at the University of Manitoba's Department of Plant Science, and works with Dr. Von Molly, and says he's researching cover crops and wants farmers' input.
"Cover crops are grown to cover the soil, and they're typically grown to provide soil cover when a cash crop is not grown," says Morrison. "By a cash crop we mean any crop that's grown to provide financial income for a farmer, such as soybean, wheat, barley, and oats. A cover crop is not harvested and popular examples would be radishes as well as fall rice. Cover crops can either be grown in the shoulder season to provide cover after cash crop harvest, but they can also be grown over the entirety of the growing season. And that can be done for many reasons. One of them is an organic farmer may do this to increase the nitrogen in the field to make it available to the subsequent cash crop. It can also be done to try and alleviate salinity issues or also in between grow crops of fruit."
He notes it's been used for thousands of years as a way to naturally keep the soil healthy.
"Ancient Egyptians used this as well as the American founding fathers," adds Morrison. "Many of them grew cover crops in their plantations. It used to be a great way to add atmospheric nitrogen into the soil before we had artificial fertilizers. But with the invention of the Haber-Bosch process which we use now to make our artificial nitrogen fertilizer, nitrogen became a much cheaper and a readily available source that farmers can use. So, cover cropping began to fall out of favour in North America. But in recent years, there's been this growing interest in conservation agriculture."
Morrison explains cover cropping is getting more popular, especially in the United States.
"Farmers in the prairies have been seeing these stories coming from America and seeing the successes, and they've been playing around with cover crops and fitting it into their rotation," adds Morrison. "So, it's still quite an ancient endeavour on the prairies, but it's growing and there's definitely momentum behind cover cropping. When I'm speaking to farmers, a lot of farmers have already tried to grow cover crops in the past few years. But there's a number of farmers on the prairies that have been growing cover crops for more than a decade."
Morrison says he doesn't have exact numbers of farmers in the Portage area that are cover cropping, noting the data has not yet come in for this year, but it is being done.
"We're trying to increase the portion of farmers from all regions within Manitoba," continues Morrison. "It's really important that we hear from the widest possible range of farmers there are just so that we can get very good results that can be applicable to all different types of farmers. So far in the prairies, we've almost heard from 400 farmers. So, slightly more than half of those have grown a cover crop, and certainly less than half have not grown a cover crop. And both of these respondents are very important."
He says he's asking you to contact him if you're a farmer, and inform him, whether or not you're using cover crops.
"It's just as important to hear why farmers aren't growing cover crops, what challenges are limiting their use, as it is to hear why farmers are growing cover crops and what benefits they see," adds Morrison. "By listening to what challenges limit cover crop use, we can identify ways to help farmers grow cover crops if they wish to try and mitigate risk, and ensure that farmers can make well-informed decision that will be more likely to benefit them."
Morrison outlines why you should use cover crops.
"Cover crops have numerous potential benefits for both soil health and environmental health as well as potentially agronomic benefits for the farmer themselves," says Morrison. "Anytime that cover crops are out there growing, they're fixing carbon. And then when the cover crop returns to the soil, they're going to increase soil organic matter which is such an important ingredient to soil health. But also, they're quite topical at the moment because anytime you're building soil organic matter which, as I say, is brilliant for ensuring that soils become well-formed with their soil physical properties and also able to hold water, it's also important because soil organic matter contains carbon. And when you build soil organic matter you're also sequestering carbon from the atmosphere."
He says the capture of carbon dioxide from the air is making the effort very popular.
"Governments are talking about ways we can essentially take carbon dioxide out of the atmosphere and put it back into the soil," says Morrison. "But also, you've got the benefit that cover crops are a good way to fix your own nitrogen on the field through growing cover crops such as legumes. Legumes, such as peas, beans, and clovers, form a symbiotic relationship with bacteria in the soil, called Rhizobium bacteria. They take nitrogen out of the atmosphere and fix it into the soil and then forms it for the next generation of plants to use. That means that there's less reliance on artificial fertilizers which take a lot of energy to produce. But also, some species of cover crops are very good at averaging and taking up excess nitrogen. So, a lot of cereal species are grown as cover crops. If there's any excess nitrogen left on that field, the cover crop will suck it up, if you like, keep it in its biomass and will ensure that it will reduce the amount of nitrogen which is lost via runoff."
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