TWIN FALLS — Building soil health does not use a cookie cutter approach. What works for one grower may not work for another, even if their farms are side by side. That was quickly apparent when a group of farmers who have formed an informal Magic Valley Soil Health Forum got together this month.
The group includes both conventional and organic growers. Many of the conventional growers are incorporating direct seed technology into their cropping system, while organic growers often have to rely on tillage. But they share the same over-arching goals — build soil organic matter and find ways to keep a root living in the soil for as long as possible.
“Weeds are the quickest way to get out of organic farming,” said Karl Joslin, an organic farmer south of Twin Falls. “We don’t want to start anything we can’t get out of.”
He is leery of using species such as hairy vetch, cereal rye and buckwheat in cover crop mixes because all three can be difficult to kill.
Todd Ballard, who farms near Kimberly, includes vetch in his crop mixes and believes it boosts nitrogen. This year he planted inoculated seed that seemed to help the vetch get started quicker and develop more nodules this fall. Vetch has been a slow starter in mixes, often not developing until the spring, right before the cover crop is terminated.
While Ballard has not had a problem with vetch persisting into the next crop, Doug Huettig has.
“I have finally come to my senses and dropped hairy vetch out of my mixes,” the Eden area farmer said. “I am a very good hairy vetch grower, I can’t kill it.”
Tillage will take vetch out but glyphosate doesn’t, Huettig said. Adding a pint of 2,4-D per acre can help control vetch, where tillage isn’t an option.
His neighbor Curtis Jones has also included hairy vetch in a cover crop mix he planted last fall for winter cattle feed. The vetch took off this spring just about the time he was ready to plant corn. He sprayed out the cover crop and intended to direct seed the corn but the ground was too compacted. Jones isn’t sure if the cows or the winter conditions or both were too blame for the compaction. He strip tilled the corn instead.
Even though he sprayed the field again, he noticed vetch was still growing after the silage corn was chopped.
“I’m curious to see if it will still be there next spring,” he said.
Buckwheat is another potential troublesome species in a cover crop mix. The seed is similar to wheat and is nearly impossible to separate from wheat kernels. Buckwheat can cause severe allergic reactions in some populations and is considered a contaminant in wheat exports.
Huettig uses buckwheat in his cover crop mixes and likes it because of buckwheat’s ability to break phosphorus away from soil particles to make the nutrient more available to crops. Buckwheat establishes quickly and can flower within 30 days of planting.
But it also dies quickly.
“A frost a county over will kill it,” he said.
Another question growers discussed was whether to apply fertilizer with the cover crop mix. Huettig hasn’t in the past but as the family’s cattle herd expands, they need more forage for the herd. All of their cover crop is grazed for winter feed.
Karl Joslin can’t use commercial fertilizers on his organic acres. He likes Austrian winter peas for building soil nitrogen.
“I’m really sold on the peas,” he said. “They are durable, they are easy to kill. They are a legume (so they fix nitrogen from the atmosphere) and even the plant has a lot of nitrogen in the biomass.”
Joslin interseeds peas with volunteer grain in the fall to provide a green chop forage for his dairy customer in the spring. Then he lightly disks the aftermath. His theory is to kill the crop slowly to keep a root living as long as possible so he admits the first pass with a disk leaves the field looking pretty ugly.
“Organic matter in (the soil) is our whole emphasis,” he said.
Other growers in the Magic Valley have had trouble getting peas to germinate or to over-winter. Joslin hasn’t experienced those problems.
“Last winter our peas looked like they had died down last winter,” he said, “but they came back with a vengeance this spring.”