Cover crops used to test theory of algae
Conservation group gets funding to help reduce phosphorus in the Thames River
The London area conservation authority has received a $500,000 boost to support its fight against high phosphorus levels in the Thames River. The funding, awarded to the Upper Thames River Conservation Authority by the Agricultural Adaptation Council, a not-for-profit group made up of more than 60 Ontario agricultural, agri-food and rural organizations, will be used to measure how effective cover crops are at reducing phosphorus in a major creek that drains into the Thames. Phosphorus, which is found in human sewage, animal waste and chemical fertilizers, has long been considered the main culprit behind the algae bloom in Lake Erie every summer.
A few years ago, the oxygen-hogging, toxin-producing algae bloom in the lake was nearly the size of Prince Edward Island.
As part of the project, expected to last three years, the conservation authority will plant more than 800 hectares of farmland within the upper Medway Creek watershed, just east of Lucan, with cover crops when the fields aren’t being used to grow the region’s top crops: corn, soybeans or wheat. This area was chosen because of the high phosphorus levels recorded there, said Tatianna Lozier, agricultural soil and water quality technician with the conservation authority.
“It was identified as a high contributor of phosphorus in the Thames River,” she said. During the non-growing season — fall to spring — leftover phosphorus fertilizer that was not taken up by that year’s crop, is left on the land, where it gets washed into water courses by rain and snowmelt, Lozier said. The goal of the project is to use cover crops, such as oats, cereal rye and radish, to keep soil covered during this time and reduce phosphorus transfer from fields to water courses. “This period of time contributes to most of the phosphorus that’s being transported from the river to Lake Erie and contributing to those algae blooms in the summer,” she said.
“So, the idea is, if we can have a cover crop and have the ground covered over the non-growing season, when you wouldn’t typically have anything on your fields, can we make a difference in terms of the phosphorus levels we are seeing on the creeks during that time?”
The project is one of a number of initiatives spearheaded by the conservation authority as it works to reduce phosphorus levels in the Thames River by 40 per cent by 2037.
Those goals are part of larger efforts spearheaded by multiple groups in Ontario and states bordering the lake south of the border to help control the algae bloom issue in Lake Erie.
“These algae blooms turn the water dark green, making it unswimmable. It also produces a toxin that can affect the liver of humans, while negatively affecting all the aquatic organisms in the lake, so it is a huge problem,” said Mark Reusser, co-chair of the Thames River Phosphorus Reduction Collaborative and vice-president of the Ontario Federation of Agriculture.
“It’s incredibly important to keep the lake alive,” he said. The problem is most prevalent in the western part of Lake Erie where, in 2014, a massive algae bloom shut down drinking-water intakes in Toledo, Ohio. Lozier said it will be hard to measure how much impact this project will actually have on the larger scale, but the hope is that if it is effective at improving Thames River water quality it can be replicated elsewhere.
“The hope is that the results from what we see in this small scale can be expanded within Upper Thames and even scaled up,” she said.