Cover crops spur slacker soils
One spring, Stud Swenson supplemented wrestling calves during calving season with nightly 5-mile runs.
After calving, he worked in morning weight training that coincided with tossing seed corn bags during planting.
Later that summer, he started swimming laps in his farm’s pond in conjunction with daily scouting walks as he traveled between his fields on his bicycle.
At harvest, Stud lived up to his name by squeezing in a triathlon between combining runs.
After harvest, though, Stud went soft. Couch time watching ESPN nixed weight-lifting crunch time. Stud swapped countryside runs for double-cheeseburger sprints. And he subbed morning swims with morning showers. Not surprisingly, six-pack soon described his beverage of choice instead of his abs.
Switch To Soils
OK, Stud Swenson is a fictional farmer. His fate, though, mirrors what’s occurring in many soils.
During the growing season, soils hums with activity of soil microorganisms that benefit crops. For example, mycorrhizae fungi create filaments on the edge of a crop plant’s roots that extend its water and nutrient uptake. Meanwhile, crop roots readily suck up nutrients and water throughout the growing season.
After harvest, though, many soils enter slacker status as plant growth exists.
The friendly microorganisms that benefit your soil starve. No crop cover leads to soil erosion. Compaction spurred by field operations remains. Water unused by the crop can hamper next spring’s planting. Unused nitrogen can escape into groundwater or tile lines.
Enter Cover Crops
They can make your soil mimic an Olympic sprinter year-round. Cover crops can extend the feeding frenzy that soil microorganisms enjoy during the growing season.
“We have to have something growing most of the year, compared to something just five to six months out of the year,” says Nick Bowers, a farmer and co-owner of KB Seed Solutions, a Harrisburg, Oregon, cover crop firm.
Cover crops also curtail erosion and break up compaction. Constant cover encourages earthworms to thrive. Earthworms create soil tunnels that aid rainfall infiltration. This nixes runoff and helps ensure that moisture migrates to crop roots. Cover crops may benefit water management.
“Farmers in eastern South Dakota and Minnesota could benefit just as much from cover crops as drain tile,” says Dwayne Beck, manager of the Dakota Lakes Research Farm near Pierre, South Dakota.
Cover crops can salvage excess nitrogen (N) and convert it into organic N not prone to leaching or denitrification. That not only benefits farmers but it also spares communities downstream from high drinking water nitrate levels and hypoxia that starves marine life of oxygen in water.
Cover crops, when combined with no-till and diverse crop rotations, are a way to deep-cycle plant nutrients like nitrogen, says Beck. “We are losing nutrients 4 to 5 feet deep that aren’t coming back,” he says.