Soil degradation is becoming an increasingly common talking point among Canadian farmers and regulators. Concern over the phenomena has been growing for decades and has driven the no-till movement in farming. But no-till is not enough. Other practices must be undertaken to help replenish the soil and to prevent further erosion.
Soil degradation is the loss of essential nutrients and organic matter in soil, caused by salinization and erosion due to natural processes such as rainfall, wind and ice, as well as practices such as tillage. Canadian Federation of Agriculture (CFA) Director of Science and Environment Policy Frank Annau says that soil degradation is a crucial issue for Canadian agriculture.
“It not only diminishes productivity, but threatens the ability of agriculture to mitigate climate change impacts,” says Annau.
A panel of experts recently testified to the Senate committee on Agriculture and Forestry, urging
David Lobb says that soil degradation occurs in all parts of the country and can take decades to recover. Much of Canada’s degradation goes back to the sixties and seventies
further attention from government on this issue. David Lobb, a professor of Landscape Ecology at the University of Manitoba, made the case for a national team of permanent staff to conduct soil surveys, terrain analysis and Geographic Information Systems analysis. Lobb spoke to Small Farm Canada about how extensive the problem of soil degradation is and how to reverse the effects.
“In the late seventies or early eighties, an economic analysis said that soil degradation caused an annual $1 billion dollar loss, in 2019 dollars,” says Lobb. “Now it’s a $3 billion loss. It’s gotten worse and the nature of the economics of crop production has changed. Farmers are producing more crops and they’re producing more high value crops, like soybeans, than they were back in the seventies. And what was a 10% loss in crop yield back in the 1970s or early eighties now means a lot more in absolute terms. The cost of lost soil is more valuable now.”
Some had hoped that converting to no-till farming systems would solve the problem, but Lobb notes that no-till doesn’t fix the problem or reverse the damage; it simply prevents it from getting worse. And even refraining from traditional tilling may not stop all damage.
“One thing people don’t realize is that any form of disturbance is tillage,” says Lobb. “It’s not just the plow, any practices that disturb the soil—seeding and harvesting crops—can actually be more erosive than all the primary and secondary tillage operations combined. Even if you eliminated all primary and secondary tillage, if you have some form of disturbance in the operation, it may be enough to resist the recovery of the soil.”
Lobb identifies three key practices that can be used to help replenish soil. First, is to grow crops that produce more biomass—corn or other forage crops will help beef up the organic matter that will help restore the soil. A second solution, utilized by many farmers in the prairies, is to import organic matter biomass in the form of manure. Lobb says many farmers use particularly rich dairy cow manure to help build up organic matter in areas where organic levels have been depressed.
The third method has to do with where displaced soil actually goes. When soil is moved by water or wind or tillage, if the field is on a hill of any kind, the soil can roll downhill. Thus, Lobb recommends the practice of soil landscape restoration.
“It’s simply moving soil from the bottom of the hill where it’s been accumulating back to the hilltop,” says Lobb. “Put a small amount of organic rich soil back on the hilltop and we see an immediate response where the yields bounce right back up. The majority of the soil that’s lost from those hilltops simply gets deposited at the bottom of the slope. So we have some areas in the landscape with half a meter to a meter of organic-rich topsoil at the bottom and it’s not being utilized. That is probably the most cost effective and rapid way to restore soil.”
Asked whether the industry at large would be likely to implement such measures, Lobb has faith in the farmers—they are the ones who developed these measures after all, and they are the ones who will be directly affected by soil degradation. He is less confident, however, that government agencies will respond appropriately.
“There is a lot of inertia and they want to do things they’ve always been doing and support programs that we’ve had for decades. Suggesting to move soil is not something that fits into their narrow little perspective of how to deal with the problem. They don’t want to accept the fact that tillage erosion is a real problem. They’re the ones that are most resistant to change, not the farmers.”
Representatives for Agriculture and Agri-Food Canada declined to make a representative available for an interview with SFC, but they did provide a fact sheet on combating soil erosion with the following recommendations.
-Soil conservation practices such as conservation tillage, mulching and structures such as terraces and grassed waterways can help reduce water erosion.-Minimizing tillage passes and controlling the variations of tillage speed and depth can reduce tillage erosion.-Landscape-based integrated soil conservation in farm fields can make these remedial measures more effective. For example, grassed waterways should be placed along natural flow paths and terrace systems should only be constructed on long slopes using well maintained grassed waterways as flow paths.
Annau notes that CFA’s efforts to stem soil degradation include the promotion of best management practices to improve soil quality and successfully lobbying for the consideration of
Frank Annau, director of science and environmental policy with the Canadian Federation of Agriculture, notes that while a reduction in tillage has shown a decrease in soil erosion over the last several decades, it is still an extremely important issue for Canadian agriculture
agriculture as an offset sector under Canada’s Carbon Offset System.
“We are currently advocating for the adoption of carbon offset protocols, which would allow farmers to sell carbon offset credits for BMPs such as conservation cropping and winter cropping,” says Annau. “In the case of conservation cropping, this reduces or eliminates the use of tillage machinery used to prepare crops for planting.”
CFA is also active in advocating that government continue funding for programs that promote research and develop for farming methods that reduce soil degradation.
— Matt Jones