The Plowdown Challenge

What happens when you remove synthetic nitrogen fertiliser from a potato system and rely instead on nutrients already present in the soil, plus those generated biologically through a legume cover crop like red clover?

That question sits at the heart of Agriculture and Agri-Food Canada’s (AAFC) Plowdown Challenge, a field-scale demonstration designed to test how far “built-in” soil fertility can support commercial potato production, and to challenge assumptions about how much fertiliser is actually needed.

Developed by science coordinator Scott Anderson and technician Roger Henry at AAFC’s Charlottetown Research and Development Centre, the project uses a simple but powerful engagement tool: a yield-guessing contest. Farmers, agronomists, and members of the public are invited to estimate the final marketable yield from crops grown under reduced or zero synthetic nitrogen inputs. The goal is not entertainment, but to engage growers and stimulate discussion about nutrient cycling, soil biology, and fertiliser efficiency in real production systems.