Cattail harvesting shows promise to aid province’s water woes

The cattail-harvesting project taking place at Pelly’s Lake sees progress in extracting overloaded nutrients and processing 
the biomass crop

Ten years after a research team first considered harvesting cattails in Manitoba, one of the lead researchers remains as enthusiastic as ever about its environmental and economic potential.

“Essentially, we have been working on this for the past 10 years. When we set out it was a small project looking at how cattails and reeds and other grasses can actually absorb phosphate and nitrogen and then how we can actually use those plants for something,” said Richard Grosshans, senior research scientist at the International Institute for Sustainable Development’s water program during a presentation at the Manitoba Conservation Districts Association’s 40th annual conference here last week.

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The project, which was originally spurred by the need to find a solution for the increasing eutrophication of Lake Manitoba, quickly expanded into a larger research project looking at ways to mange the landscape, preserve the environment while growing the economy.

“Most of you likely know about Lake Winnipeg and the issues that we have there. That was really the reason we got into this project,” said Grosshans. “We have been looking at better, more innovative ways to manage the landscape and cattails are one of the plants we are really interested in.”

Pelly’s Lake

Since 2012, researchers have been on site at Pelly’s Lake near Holland, Man. actively harvesting cattails as a means to extract overloaded nutrients, increase site biodiversity and improve surface water management and flooding.

“Pelly’s Lake is an active water retention project now. The control structure was active for the first time this year,” said Grosshans. “It is flooded in the springtime and creates an amazing wetland habitat, by midsummer the water disappears and the cattails emerge, soaking up all the phosphorus and other nutrients. This creates an amazing biomass crop that we harvest in the fall.”

The IISD has used various pieces of equipment for harvest but has found recent success with the rotary disc mower.

“It is an amazing piece of equipment for cutting cattails. It has the conditioning rollers that bite into the cattail and help to draw out the moisture,” said Grosshans. “We found when we compared it to the swather, it was cutting drying time in half and if we can draw that water out faster, we can be baling faster.”

Grosshans said since they began harvesting, they have removed 1,200 tonnes of material and 1.5 tonnes of phosphorus from the Pelly’s Lake system.

“In north Ottawa, researchers calculated that if they harvested 300 acres of cattail, of the 600 acres of cattail at their site, they can remove the equivalent of all of the phosphorus that comes into that system on an annual basis. So that is pretty significant and promising for us here,” said Grosshans.

The IISD has also been working with the City of Winnipeg and other municipalities on harvesting ditches.

“In terms of the highway ditches, you will see that everything is mowed, and the materials are left in the ditch. This is releasing all of the nutrients and in the spring enabling them to move downstream quickly. Harvesting and removing that material can have a number of benefits.”

IISD researchers see promise in harvesting cattails to reduce nutrient levels in overloaded waterways.

IISD researchers see promise in harvesting cattails to reduce nutrient levels in overloaded waterways.
photo: IISD

Working with the biomass crop

Along with harvesting the cattails and monitoring nutrient levels, researchers have also been looking at the different market avenues for the biomass crop.

“How can phosphorus and cattails actually be valuable? How can we reuse the phosphorus that is in those plants? The project quickly grew into a research program and we formed this bioeconomy program, looking at different things in the lab like liquid fuels, biogas, compost, and organic fibre,” said Grosshans.

The IISD began to create fuel pellets and cubes that were put into a biomass burner. According to Grosshans, this is an efficient system that produces very controlled emissions.

“We can use things like cattails, wheat straw and other agriculture waste, to actually create low-carbon energy,” he said.

IISD has been looking at preparing these processed fuels and says the ban on using coal for space heating may create new demand for the product.

“This mainly affects Hutterite communities that have been burning coal for heating. By 2017 they will need to be switched off to something else. Many of them will be switching to natural gas, electric or biomass-based heat,” said Grosshans.

Ditch harvester with water in drain.

Ditch harvester with water in drain.
photo: Chris Reynolds

Most recently the project has begun moving towards commercial processing.

“We use the bale shredders, we have been testing different-size pellets, cubes, etc., and burning them to see what works the best. We have enough cattail material to make about 1,500 tonnes of mixed product. That is very exciting.”

Grosshans notes that while some of the project’s outcomes require testing to see value, the environmental benefits of the project are clearly visible at the Pelly Lake site.

“When we began harvesting in 2012, the site was fairly desolate with dense cattail growth and very few ducks and geese. This year, when we began flooding in the springtime it was amazing to see all of the wildlife. There is clear evidence that harvesting cattails has helped to restore the biodiversity of the habitat,” said Grosshans.

About the author

Reporter

Jennifer Paige

Jennifer Paige is a reporter centred in southwestern Manitoba. She previously wrote for the agriculture-based magazine publisher, Issues Ink and was the sole-reporter at the Minnedosa Tribune for two years prior to joining the Manitoba Co-operator.

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