Potato Grower Highlights Summer Cover Crops

Published online: Jul 26, 2019 Articles Candace Krebs
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Source: Ag Journal

As a trailblazer in adapting regenerative, low-input farming practices for the San Luis Valley, Rockey Farms continues to tweak production methods and experiment with new approaches while producing some of the region’s tastiest potatoes.

In mid-July, brothers Brendon and Sheldon Rockey hosted a field day for around 100 visitors from across the state and beyond, offering them a chance to observe practices on the 600-acre irrigated farm northwest of Center.

The Rockeys grow 26 varieties of potatoes, mostly for seed but, also, for the fresh market. Brendon oversees production, while Sheldon is in charge of marketing and seed certification.

Over the last decade, Brendon’s goal of moving away from high-water-consuming barley while still rotating crops and maintaining diversity pushed him to become a world-recognized leader in the adoption of cover cropping.

The farm’s chief cash crop — potatoes — is now rotated with dense, multi-species plantings of annual covers that include peas, vetch, millet, fava beans, buckwheat, sunflowers and even okra.

In the last couple of years, Brendon added quinoa to the rotation.

“It’s not economical to take potatoes out of production to grow it, but what I do is rotate it with my cover crops,” he explained.

One of his newest experiments involves finding the ideal companion crop to grow alongside quinoa, which produces a small round grain popular with consumers.

He’s currently growing it with buckwheat and crimson clover. The buckwheat and quinoa will be harvested together later this year.

Rockey’s first attempt at finding a companion crop was a bust. The flax he tried ended up producing seeds that were too similar to the quinoa and hard to sort out.

“Paul still cusses me about that flax,” Rockey said referring to Paul New, a neighboring farmer and the founder of Colorado Quinoa LLC.

New, who was in attendance at the field day, said the mixture of flax and quinoa is edible — he’s still eating it for breakfast himself — but it’s not something easily marketed through commercial channels.

Colorado Quinoa recently signed an agreement with The Annex at Ardent Mills to provide marketing and distribution support. New said he expects demand for Colorado-grown quinoa to ramp up under the new deal.

“We’ve already doubled our acreage here in the valley this year,” he said.

The Rockeys invited another local farmer, Tyler Mitchell, to talk about his experience growing quinoa. Mitchell started out with 25 acres four years ago but is now up to 600 on his 2,000-acre farm.

Controlling weeds is a significant challenge, especially since there are no herbicides labeled for quinoa, Mitchell said. But at a price of around 65 cents a pound, quinoa can bring in more profit than barley in some years, he said.

While buckwheat is considered a menace in the wheat industry because it contaminates the grain, the plant with delicate white flowers is one of Rockey’s personal favorites because of what it contributes to soil health and beneficial insect populations.

Only after volunteer buckwheat seed started coming up in his subsequent potato crops did it occur to him there might be benefits to having other plants scattered in the same fields with the potatoes.

“It costs me $8 an acre to do (the companion cropping), and it hasn’t caused us any serious problems at harvest time,” he said.

The improved porosity of the soil is one of the biggest benefits he’s seen so far. Proper soil texture allows the ground to breathe and infiltrate water. Under the new management system, the farm needs only 9 inches of water to grow a potato crop, far less than the roughly 21 inches most San Luis Valley farms require.

He’s also noticed a big difference in the tracks left by the center-pivot irrigation sprinkler as it crosses the field. The soil is simply more buoyant and resilient.

“I don’t think we put enough emphasis on soil structure in our industry,” he said.

But over time he concluded the benefits to soil health and lower input costs on the ensuing potato crop more than covered the expense.

Another thing helping to make the economics work is that three years ago he teamed up with a local farmer, Dave Brown, who grazes cows on the covers.

Brown moves the cattle every other day and pipes water for them through the irrigation sprinkler.

Brown has sheep as well as cattle, and Rockey is excited about bringing another livestock species into the rotation. Brown is planning to graze sheep on part of the acreage for the first time this fall.

The two agreed that communication is key to making the agreement work. Rockey originally approached Brown with the cover crop mix he wanted to plant, but then traded out sorghum sudangrass with millet after Brown raised concerns about the potential for prussic acid poisoning.

Together they also learned that if the cattle were left in one portion of the field long enough, they could eventually be trained to clean up less palatable problem plants like pigweed.

Rockey used that example to highlight the importance of management.

“It’s not just about bringing cattle out here and now I automatically have improved soil health. Managing the cattle properly is the key,” he said.

Grazing cover crops is still rare in the valley. Rockey admitted part of the reason is timing. Most livestock producers have access to summer pastures, so May-planted cover crops following potatoes provide roughly eight weeks of grazing when demand for forage is low.

Still, Brown has been pleased with the cows’ performance. He described turnips in a cover crop mix as “one of the best feed sources you can produce.”

During the tour, visitors also had the chance to stand next to a flowering strip abuzz with native pollinators. Planting flowering strips within and along the edges of the farm is a Rockey innovation that other farmers in the valley are starting to adopt.

Early studies show that these blooms reduce the incidence of potato virus Y, a dreaded potato disease. When virus-carrying aphids visit the pollinators, they deposit the virus there instead of transmitting it to other potato plants.

Rockey has reduced his commercial inputs dramatically. But what made it possible was investing in research and experimentation to arrive at improved farming practices, he said.

“The driving force behind what we’re doing was my uncle. He just didn’t want to be around the chemicals any more,” Rockey recalled. “But the way I describe it is that you have to earn the right to farm without all of the traditional inputs. You have to manage what you do in a whole different way.”