Grower uses cover crops to reduce input costs for spuds
By JOHN O'CONNELL
FORT HALL, Idaho -- For the past two seasons, Brendon Rockey has planted peas, chickling vetch and buckwheat in the same rows as potatoes, using a specially designed seeder.
The Center, Colo., specialty and seed potato grower doesn't harvest his so-called companion crops, which trellis up his potato plants. They're intended to lend nitrogen and organic matter to the soil.
After spud harvest, seeds from his peas produce a cover crop, providing additional soil health benefits. Rockey, who spoke March 6 at a Natural Resources Soil Conservation Service forum in Fort Hall, said the slight yield bump from his companion crops compensates for his $4 per acre investment.
After years of working to add crop diversity to his farm and more closely mimic nature, Rockey believes he's increased his profits, reduced disease risk and dramatically cut back on input costs.
"We don't spend a single dollar on anything ending in 'cide,'" Rockey said.
Rockey likens conventional agriculture's reliance on inorganic fertilizer and chemicals to an addiction. When his family first tried cover crops in the early 1990s, even university researchers advised it was a bad idea. Nonetheless, Rockey's farm went "cold turkey," bringing in compost and cutting out inorganic fertilizer. He now believes a gradual shift would have worked better.
To supplement compost, his family started planting Sudan grass as a cover crop. Three years ago, he switched to a mixture of 10 cover crops, including three legumes to fix nitrogen for the other plants. He adds no outside nutrients for his cover crops, and the only tillage on his farm involves discing cover crops into soil.
"When we brought in multiple species, it brought us to a whole new plateau," Rockey said. "We're still cutting back on inputs every year."
Three years ago, Rockey compared costs of 120-acre fields on his farm and a neighboring conventional farm. The neighbor earned $26,160 in malting barley sales while Rockey spent $11,780 to plant cover crops. However, Rockey calculated he offset the difference through reduced water and nutrient expenses, and zero chemical costs, to grow his spuds the next year.
"It's not costing me anything to invest in my soil," Rockey said.
He also believes his soil health protects his spuds from disease and helps them store better.
"Our limiting nutrient is carbon," said Ray Archuleta, an NRCS conservation agronomist from North Carolina. "Our soils are so depleted, if we can hit the carbon cycle, everything else will come. What Brendon is doing is regenerative, restorative."
Without the buffer of their grain, Oakley, Idaho, crop consultant Aaron Firth questioned Rockey how growers could have survived low 2012 crop year spud prices.
"If you can grow a crop for half as much, you're not so vulnerable to low potato prices," Rockey responded.
Some local farmers said they've had trouble getting cover crops to grow, a problem Rockey said can be addressed with multiple species.
After barley harvest prior to planting spuds the next season, St. Anthony, Idaho, grower Doug Hanks has planted a cover crop of mustard for a carbon source and natural nematicide. Hanks believes it's been a cost-effective investment.