Southwestern Ontario farmers are taking the first steps to discover how phosphorus that fuel Lake Erie’s annual algae bloom could be reduced to levels that don’t cover the lake in slime. It’s a small step, but one that could pave the way for larger reductions in Canada—and possibly show how to shrink the much larger volume of phosphorus runoff from farms on the American side of the border, particularly around the Maumee River in Michigan.
In a report released this month, U.S. government officials and state academics estimate the harmful algae bloom in the western basin of Lake Erie will be smaller in 2016 than in previous years. That’s welcome news after the summer of 2014 saw a bloom large enough that it threatened the water supply for Toledo, Ohio.
In a pilot collaboration between the Ontario Federation of Agriculture and the Great Lakes-St. Lawrence Cities Initiative, OFA members will investigate ways of reducing phosphorus runoff in the Thames River watershed, which runs southwest through Ontario from the London area to the Canadian side of Lake St. Clair (and whose pollutants run from there into Lake Erie.)
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“Farmers recognize they have to change practices,” says Neil Currie, general manager at the OFA. “But we need research. We don’t even have good baseline data.”
Currie says the pilot will initially identify major sources of phosphorus in the Thames watershed and look at methods to control them. The Thames is a small contributor to Lake Erie’s overall phosphorus problem: about 10 per cent of the phosphorus that flows into the lake from the Detroit River originates in the Thames watershed, or 350 tonnes a year. By comparison, the agriculture-heavy Maumee River in Michigan contributes an estimated 3,800 tonnes annually. The U.S. and Canada have agreed to reduce phosphorus flows into the lake’s western basin by 40 per cent. Researchers believe a reduction like that will eliminate the largest algal blooms in nine of 10 summers.
It’s not a simple task to get farmers to change practices that have worked for them: anything that might reduce crop yields, and therefore the incomes on which farmers depend, can be seen as a threat.
Another complication is that American states have relied mostly on voluntary action instead of regulation and law: state legislators are leery of being seen to impose new rules and higher costs on struggling farmers, and financial rewards for better conservation practices are generally slim. That’s meant weaker results according to Margaret Kalcic, a post-doctoral fellow at the University of Michigan.
“There’s been a lot of effort and money put into conservation, but it’s fallen well short of its goals… there’s still science gaps, and there’s also gaps between getting the science to regulators and people making decisions on the farms,” Kalcic says.
“Everyone’s reluctant to require specific actions by farmers, even in a conservation organization like ours, because each farm is different,” says Mike Shriberg, regional director of the U.S. National Wildlife Federation. “But it is going to require some increased regulatory oversight—voluntary measures have not worked.
“Ohio and Michigan have submitted draft plans, but they essentially say, ‘We’re gonna take what we were doing before and do more of it.’ Our perspective is that if it hasn’t worked for 20 years, doing more isn’t going to get us to 40 per cent.”
In Ontario some of the easiest changes have already been made: for example, spreading manure on frozen fields causes it to sit on top instead of being worked into the soil. The first hard spring rain washes it off the frozen ground and into the watershed. Ontario has been regulating the use of manure on frozen fields for more than a decade, while Ohio adopted similar rules in 2014.
That’s led some, including the OFA, to worry that reductions in Ontario will be more difficult and expensive compared with measures in the U.S. It’s the law of diminishing returns: Ontario has already made the cheap and easy changes, but still has to match the 40 per cent promised by the U.S.
What is clear is that there’s no silver bullet that will make reaching the 40 per cent target easy on either side of the border.
“There’s multiple best practices that are going to be needed around the basin,” says Cale Selby, manager with the Ontario Ministry of Agriculture, Food and Rural Affairs. “Because of the dynamics of agriculture, it’s important we have flexibility.”
“Flexibility” means that the government will tackle some problems through regulation (the ministry is looking at the nutrient-rich water disposed of by greenhouses) while other problems will be dealt with by public funding. The province is spending $16 million over four years to encourage improvements in farming practices in the Lake Erie and Lake Huron watersheds. That money will go in part to grants for equipment upgrade.
For example, a farmer could get a grant to buy equipment that deposits fertilizer under the soil instead of spraying it on top, reducing runoff by working the fertilizer into the earth.
But the reality remains that regulators don’t have a clear picture of what practices will work best to reduce runoff, or how long it will take to see measurable changes. To top it all off, some of the practices farmers have adopted over decades to prevent soil erosion may be making the phosphorus problem worse.
Kalcic was a co-author on a recent study showing that reducing phosphorus flows into Lake Erie from the U.S. side of the border by 40 per cent is achievable with aggressive use of the best available management practices. This would have to include taking some cropland out of production entirely and turning it over to grassland, angering farmers who would they lose their livelihoods.
“It’s an extremely complex and dynamic system, and a lot of it is not well understood at this point. We know climate change will have a huge impact, we know invasive species will have an impact, we know land use changes will,” says the ministry’s Selby. “It’s complex, and we’re going to have to learn as we go.”