A large majority of farmers in Western Canada have adopted zero-till systems — with the exception of those in the Red River Valley who are dealing with heavy, wet clay soils where tillage is just a fact of life. Most farmers understand the many benefits of zero till, such as prevention of soil erosion, better moisture retention and improved soil structure and soil organic matter content.
But tillage has been suggested as a partial solution to some disease issues and management of some weed species.
Does some kind of tillage operation — for a specific reason such as disease management or weed control — have a place in a no-till system in Western Canada?
Yield and Disease
The last study that specifically looked at the impact of tillage on crop yields, weed numbers, foliar disease and nutrient availability in a long term, zero-till system was done from 1999 to 2002 by Byron Irvine, Alan Moulin and others at Agriculture and Agri-Food Canada’s Brandon Research Centre.
The study found that a tillage operation in one year of a three-year rotation, which included canola, did not reduce disease levels or yield. “If you really wanted to have an impact on disease you’d probably have to till with some sort of a plow and get full inversion, and that’s not realistic in our environment,” says Byron Irvine, director of research development at AAFC’s Brandon’s Research and Development Centre. “We were doing stuff that was realistic for people to do in our environment and the impact was really negligible.”
Weed numbers increased by up to 30 per cent in the tillage year and were higher the subsequent year, but returned to previous levels the second year after tillage, indicating that a single tillage operation won’t have a long-term negative effect on weed pressure or yields.
”We came to the conclusion that the world didn’t fall apart when you went back to doing a little bit of tillage when people are doing it because they really had a need for it,” says Irvine. “That was the premise of the work in the first place.”