For many farmers, the growing season is finite each year, and choosing the right rotation can produce perpetual soil health and yield benefits. But for Coolidge, Ariz., farmer Robert Boyle, strip-tilling, planting and harvest are continuous tasks.
Crop rotations differ by field across his 1,200-acre operation, but he primarily grows corn, sorghum, wheat and alfalfa. During a recent visit to Boyle’s farm, I had the chance to see this diversity up close with a field of shoulder high sorghum opposite a plot of 2-year alfalfa almost ready for its 11th cutting.
“One side of the farm is sand, which will set up like cement, and the other side is more of a clay loam,” Boyle says. “We typically have about a 50/50 rotation between alfalfa and corn and then the corn fields will either get winter wheat or barley, depending on what the nutritionist wants that year.”
This year, Boyle made an experimental addition to the rotation, drilling in 12 pounds per acre of hairy vetch as a cover crop on 70 acres ahead of strip-tilled corn for silage. The field is in a rotation with alfalfa, and Boyle wanted to add a little more diversity to further develop soil biology and potentially retain additional moisture and nutrients.
“My goal is to change up the monoculture I’ve created in my cropping system,” he says. “The problem we face is that alfalfa is a 3-year crop, and corn is a 1-year crop. But we end up doing two to three crops of corn before we’re ready to rotate alfalfa, and corn-on-corn doesn’t work here because we’ll get 40 tons that first year of corn and then 25 that last year.”
Boyle’s plan is to let the hairy vetch get 10-12 inches tall then either do a burndown or shred the cover, then strip-till and plant corn. Based on his research, he could get upwards of 100 units of nitrogen carryover, but he’d be satisfied to get even 30.
He’s also hoping to make more efficient use of an abundant winter water supply, to help offset limited availability in summer.
“We get canal water and well water, but the canal water is rationed down in heat of summer, so I have to cut back on my growing acres for certain crops,” Boyle says. “If I can grow a crop cheaply, while also building the soil up and cut back on commercial fertilizer usage next year, I can see expanding cover crops from one-tenth of my corn acres to all of them.”
What benefits are you seeing from cover crops in your strip-till operation? Share your story with me at (262) 777-2441, or send me an email at firstname.lastname@example.org.