Agriculture Canada scientists are testing a new way to keep nitrates from farm fields out of rivers and streams at the research station in Harrington north of Charlottetown.

Vernon Rodd is keen to see the results of this trial. (CBC)

Nitrates in streams can lead to blooms of sea lettuce. When the aquatic plant dies, it sucks oxygen out of the water. Those anoxic conditions can choke other life in the water.

The Agriculture Canada experiment uses underground pits filled with wood chips to filter nitrates from farm runoff. During and after rain storms the runoff water from fields is filtered through the wood chips before its runs into rivers.

Researcher Vernon Rodd said experiments in other parts of North America show wood chips can do a good job of soaking up nitrates.

"Probably a 90 per cent reduction," said researcher Vernon Rodd.

"[It] remains to be seen. This is part of the research part of it. If we knew exactly what we were going to get, we wouldn't be doing it."

The wood chips themselves can eventually be used as compost on fields, putting the nitrates back where they were meant to be.

The experimental system should be up and running this fall. It's a first on P.E.I. and one of the few systems in Canada.