Research project in P.E.I. potato field confirms the oldtimers were right about manure

A research scientist on Prince Edward Island has confirmed what many Island farmers knew decades ago when it was common to raise cattle and grow potatoes on the same farm: Manure is good for spuds. 

So good, in fact, that a recent study showed a small amount of manure added to cover crops grown before potatoes were planted in a field increased marketable yields by 26 per cent. 

Judith Nyiraneza, the study's author and a Charlottetown-based research scientist with Agriculture and Agri-Food Canada, said manure has long been known to regenerate soil and boost cover crops. 

"So far, we have seen very interesting results around manure application," Nyiraneza said.

"When we apply a very low amount ... we were able to see that manure boosted yield by 26 per cent, but it did also increase the soil nitrogen supply capacity by 44 per cent."

Nyiraneza said the numbers are impressive for such a small amount of manure, around 20 metric tonnes, and she is now looking at how a wider use of the treatment could benefit the environment.

"It would be an excellent soil regenerative management practice if we can see that it does also reduce greenhouse gas, and does increase the carbon sequestration," she said. 

Nyiraneza said there's been interest from potato growers in partnering with local cattle farms to source the manure, while also providing grazing land for the cows. 

"There is a win-win situation where their farm is getting feed for free and the potato growers are also having manure on their land without needing to transport it."

She's working with three potato growers in a combined potato-livestock project through Living Lab — P.E.I.

"I think we are realizing that you cannot push the soil to produce more and more," she said. "Eventually you have to go back and try to regenerate it if you want to sustain the yield for your future generation."

Nyiraneza hopes to have some "interesting results" to share next year, comparing carbon sequestration between 2017 and 2024.

At least one P.E.I. potato farmer has already made the move back to a combination of cattle and potatoes.