Radishes were popping out above the soil line along a pipeline corridor on the Shane Hodenfield farm, a clear sign of terrible soil compaction.
A durum crop the year before had yielded only single digits — or even nothing at all — and did so again even after Hodenfield’s cover crop attempt.
That’s when the grower, who farms north of Ray, contacted cropping specialist Dr. Clair Keene with Williston Research Extension Center, to get guidance on what he could plant there that would make the area productive again.
With Keene’s help, a large-scale demonstration was set up using four different mixes of alfalfa and grass, to see how the different combinations would perform both along the pipeline and in an undisturbed area. While not a replicated trial, the project is nonetheless instructive when it comes to pipeline reclamation and was the site of a field day, Thursday, June 20.
The combinations seeded at the site in 2018 were as follows:
• Rugged alfalfa+ meadow brome+ pubescent wheatgrass,
• Rugged alfalfa+ AC Saltlander hybrid wheatgrass,
• AFX457 alfalfa + meadow brome + pubescent wheatgrass,
• AFX 457 alfalfa + AC Saltlander hybrid wheatgrass.
Keene recommended perennials for the reclamation, because they provide continuous soil cover and deep roots to help cycle nutrients and improve soil structure.
“Perennial roots, and alfalfa especially, get really deep in the soil,” she told the Williston Herald. “It adds carbon in the soil and it’s holding that soil in place year round. It’s there fall and winter protecting the soil against erosion. And because it starts growing as soon as the snow melts and is warm enough, it can compete with the weeds.”
She also discussed how to prioritize soil improvement over forage production during the Field Day, by not cutting the stand as frequently.
“In northwest North Dakota, I’d expect that to be two cuttings per year after the establishment year, but it may only be 1 cutting if we get dry,” Keene said.
Soil health specialist Keith Brown also presented during the field day, and demonstrated how water infiltration can be used to gauge how a reclamation is going.
In the demonstration, the undisturbed soil absorbed an inch of water in less than 10 minutes, while the pipeline took more than two hours.
Dryland research specialist Meredith Miller talked about an ongoing pipeline reclamation project at Williston Research Extension Center. Compaction there is being monitored over time with a cone penetrometer.
The results so far indicate the roadway used during the pipeline installation is a more challenging area for subsequent crop production than the pipeline itself, due to compaction.
Keene doesn’t have funding for a study of the pipeline corridor, but does plan to keep sampling the biomass, to see how the forages are doing.
“There would be a lot of room to learn about how the soil is changing over time, if we had funding,” Keene said. “I have not been doing any measurements on compaction or increases to soil organic matter or changes to pH. But there are a lot of things that we do need to know about how the soil changes under the perennials and how quickly it can happen in a pipeline situation.”
A question Keene would particularly like to be able to answer, and that she hears often from growers, is how long before such corridors can be farmed productively again.
“We know it will take a while, but we don’t know how quickly it will change,” Keene said. “It definitely merits further investigation.”