With 2,400 acres of unseeded land on his farm north of Souris, Man., Andy Barclay is definitely in unfamiliar territory this summer.
Like many farmers in Manitoba and southeastern Saskatchewan who are staring at soaked, weedy fields in July, Barclay isn’t sure what he will do with his cropland next year.
Barclay said he might seed winter wheat later this summer if his land dries up in time.
However, Yvonne Lawley, associate professor of plant science at the University of Manitoba, said farmers with wet acres may want to seed a cover crop this year.
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Lawley was previously an extension agronomist with North Dakota State University, where farmers commonly use cover crops such as cow-pea, hairy vetch and millet to build soil structure, suppress weeds and add nitrogen to the soil.
However, after taking her new position at the U of M, Lawley was surprised that cover crops are not more widely adopted in Manitoba.
“I think there are (a few) people practicing cover crops here. I’m just trying to connect with those growers and find out what they are doing.”
Martin Entz, a plant science professor at the U of M, said Manitoba growers aren’t as familiar with seeding cover crops in summer or after harvest because conditions around Bismarck, N.D., are substantially different from the growing season in Brandon.
Nonetheless, Entz has conducted research in Manitoba demonstrating that cover crops can contribute nitrogen and benefit cropping systems in this province. He and his graduate students have even looked at a scenario similar to this year, where acres couldn’t be seeded in the spring because of flooding.
“You can grow vetch. You can seed it now and you can let it grow all fall and kill it next spring. That hairy vetch crop will make a hundred pounds of nitrogen (per acre), or more.”
Other cover crops can also contribute to soil fertility, he added.
“If you were to grow fababeans or soybeans, you’re probably looking at closer to 60 to 80 lb. of nitrogen that you’re going to introduce into the soil, if you seed this time of the year.”
However, Entz understands that prairie growers with soaked acres may not want to seed a cover crop this summer.
“This is new territory for most farmers. Maybe it’s not surprising that many farmers would be more comfortable just chem-fallowing their fields or tilling them and leaving them,” he said.
“They don’t have much experience with mid-season cover crops.”
Lawley said farmers who are new to the concept should consider a cover crop cocktail.
“I think going with a mixture is a really smart idea. I’m not saying it has to be a 16-way mix.”
A cocktail of species will provide insurance that something will grow across the variable conditions within a field from extreme wet to weedy to dry.
She also said producers don’t have to spend a lot of money buying seed for an exotic cover crop.
“Think about what you have on hand (such as canola) and whether those crops are able to meet your objectives,” such as taking up water or fixing nitrogen.
Entz said many fields are covered with weeds this summer, which means farmers have to decide if their fields are in good enough condition to grow a crop this year.
“There will be fields where the answer to that question is no.”
A session on cover crops will be held in Carman, Man., July 20 during the University of Manitoba field days.
WHAT ARE COVER CROPS?
•Cover crops are defined as low-growing understory crops that often grow outside of the main growing period. They add soil nitrogen, reduce soil erosion, increase soil quality and suppress weeds.
•Green manure crops are grown specifically to replenish the soil system with nitrogen, but also phosphorus and other nutrients.
Source: University of Manitoba
FOR MORE ON COVER CROPS
•The U.S. Department of Agriculture has assembled a periodic table of cover crops. The table lists 46 species of cover crops and provides information on potential benefits of each species, suitable growing conditions and other attributes. The table can be found online by typing “usda cover crop chart” into Google.
•The University of Manitoba has detailed information on its cover crop research at www.umanitoba.ca/outreach/naturalagriculture/.
