Building the Soil Before the Potato Goes In: Cover Crop Sequencing at Perry Farms

Perry Farms | Regenerative Alberta Living Lab

Harold Perry has been refining what goes into the ground before his potato crop for years. On Perry Farms near Chin, Alberta, the rotation leading into potatoes has become one of the more layered parts of the operation, and one of the areas where the most active iteration is happening.

The starting point was a practical one. Potatoes are hard on soil. They require tillage, they leave the ground exposed, and they create conditions where disease and pest pressure, particularly nematodes, can build over time. Harold's response has been to treat the years between potato crops as an opportunity rather than just a waiting period.

The current approach uses relay cropping and multi-species cover crop mixes timed carefully ahead of the potato year. After a fall rye crop comes off, Harold plants into that stubble, sorghum sudan grass in one rotation, and a mix that includes Fredolancus oats in another. The oats are being tried specifically for their potential to reduce nematode numbers, a known contributor to early dying in potatoes. Research from the region suggests this variety has promise for suppressing nematode populations in similar soil conditions, and the Perrys are working through what that looks like in their specific fields.

Timing has turned out to matter more than Harold initially expected. Getting a 12-species mix in by August 15 to 20, rather than later in the fall, means the plants and their root systems have time to develop meaningfully before winter. A cover crop that reaches a foot of top growth with root depth to match carries more biological momentum into the spring than one that barely establishes. That observation has shaped how Harold now plans the whole rotation calendar.

The spring transition involves power hilling the standing cover crop into the soil before potatoes go in. One of the things the Regenerative Alberta Living Lab has been tracking at Perry Farms is what that tillage event does to aggregate stability, a key indicator of soil structure. The working assumption coming in was that power hilling would show some measurable decrease. So far, the data is not showing that expected decline. It is still early, and sampling continues, but it is a result worth noting.

Being able to pick up a result like that on a working potato farm, without pausing the operation to run a controlled trial, comes down to how the Living Lab is designed. It uses predictive soil mapping built from the landscape itself: topography, moisture patterns, vegetation, and the other factors that make one part of a field behave differently from another. That mapping accounts for the natural variability across Harold's fields, so sampling points can be placed and compared in a way that holds up, even though he is farming adaptively rather than holding conditions constant. The map gives the research its structure, which is what frees the producer to keep managing the way real conditions demand.

That is the gap this kind of work has always run into. Traditional research wants standardized protocols and controlled variables; a working farm runs on real-time adjustments and context-dependent choices. Farming doesn't wait for a protocol. The weather turns, cattle don't show up, a planting window opens early, and the producer adapts. In a conventional trial those adjustments read as broken conditions. With the mapping underneath it, they are captured instead, along with the reasoning behind them, as part of the record. The same map Harold uses as a day-to-day management tool is the data infrastructure the researchers use to compare across fields, seasons, and operations.

That flexibility showed up in one season when Harold applied compost and digestate ahead of a cover crop, then power hilled it all in before potatoes. In a separate field, the plan had been to bring cattle in to graze the cover crop, adding fertility through manure in the process. The cattle weren't available that season, so the cover crop was power hilled in as green manure instead, and Harold describes both fields coming in with strong results. Rather than a disruption to a trial, that switch is exactly the kind of real-world adaptation the mapping is built to capture, and it points to some flexibility in how the fertility inputs can arrive. It also shows how the cover crop work connects to the rest of the system: the digestate and compost off the anaerobic digester (see Closing the Loop), the biological fertility Harold is building through the rotation, and the goal of a soil that cycles nutrients on its own terms.

Harold describes that goal in straightforward terms. He wants a soil that cycles nutrients well, infiltrates water, and supports a plant healthy enough to manage disease pressure without needing him to intervene as much. Getting the cover crop sequencing right, species selection, timing, and how it connects to everything else in the rotation, is one of the main ways he is working toward that.