The golden wheat heads that glisten as harvest nears in one field in north-central Iowa mimic the early 1900s, when wheat was an Iowa crop kingpin.  

Then again, it’s 2024. Wheat faded as a cash crop long ago, replaced by a sea of soybeans and corn.

Still, wheat in this field near Humboldt is a tool in cover crop and relay cropping systems used by Doug and Kim Adams. These strategies are rooted in no-till and strip-till systems that Doug Adams had observed on a trip to Jerry Crew’s farm near Spencer back in the 1990s.

“At the time, we did conventional tillage, but my dad was also always open to try new things,” Adams says. “Jerry told us that if you farm gumbo soils, look at the fence rows,” where the soil is not tilled.

The fence-line soils were porous and pliable and brimmed with earthworm activity. Crew told Doug Adams that tilling gumbo soils, or heavy clay soils, shattered soil structure. Reducing or nixing tillage could boost a field’s soil structure, akin to fencerow soils.

This visit and other meetings helped spur the Adameses to convert to a mix of no-till and strip till in 2000. “We no-till our beans into cornstalks, and strip-till our corn on bean ground,” Adams says. They complemented this step with cover crops in 2012.

“The spring of 2012 was a warm one,” he recalls. “We saw good cover crop growth, and that got me excited about the potential.” 

Related:How to grow a local wheat seed brand

Better water infiltration

The shift to no-till and strip till enabled the Adamses to boost soil structure.

“The main thing I’ve learned from improved soil structure is how quickly water infiltrates into the soil,” Adams says. “During dry weather, I find water flowing in tile lines even after a small rainfall event. If you’re doing a lot of conventional tillage, rainfall might not make it to the roots.”

“Well-structured soils also make a home for soil microbes,” says Jodi DeJong-Hughes, a University of Minnesota Extension educator. Beneficial soil microbes aid myriad plant processes, such as improved nutrient transfer.

“One handful of productive soils can hold about 10 billion microbes,” she says. “If you build a home for them with good soil structure, they will come.”

Leaving surface residue via less tilling also helps keep soil in place. 

“A raindrop falls at a speed of about 20 miles per hour,” Adams says. “When you have residue on the surface, it removes energy out of the raindrop and results in less soil movement when it hits.”

Slashing tillage requires a mindset shift.

“I've always said that with no-till, you probably should not look at your fields until after the Fourth of July because they’re kind of ugly,” he says. “But once crops get growing, those fields are like all other fields.” 

Related:Wheat: Scab Stryker to combat head scab fungal disease

Cover crops helpful

Cover crops bring myriad benefits, such as capturing excess nutrients. Since cover crops also compete with weeds, they’ve helped the Adamses cut herbicide use.

“I haven’t eliminated herbicides, but I have reduced their use quite a bit,” Adams says. “A good cover crop stand can act like a residual herbicide to help manage waterhemp.”

Challenges do exist, though. In a wet spring, terminating cover crops before planting can aggravate already wet soils by shading them. Rather than risk delayed planting, Adams “plants green” into standing crops and kills them with a contact herbicide after planting. They also have used a roller crimper for termination.

“Planting green sounds scary, but it is actually easier,” Adams says. “Once a cover crop is dead, it’s not as attached to the soil and tends to drag or get wrapped around the planter. What I like about planting green is there’s no concern about wrapping [of cover crops with the planter]. There’s nothing like planting into a green small grain, with it waving in the wind.”

Adams has tested numerous cover crop mixes to match the right mix to each field.  Some species may vary in performance between fields and years.

Related:USDA’s 10-year wheat projections

“Every year is going to be different, so it’s good to plant different species,” he says.

Adams has both aerially broadcast and drilled cover crops in the fall and spring, respectively.

“Broadcasting them is easy to do, but you don’t always get the best stands,” he says. “When we drill cover crops in the spring, they can catch up in growth.”

Relay crops mix things up

It’s here where winter wheat plays a part. The Adamses use it in a relay cropping system where soybeans are planted into winter wheat that has previously been seeded in the fall.

“The idea is to get 75% of a wheat crop and 75% of a bean crop [compared to one crop annually],” Adams says. “Even if we get 75% of a wheat crop and just 50% of a bean crop, it’s better than 100% of one crop.”

Adams has also planted soybeans into cereal rye, which has its drawbacks and perks.

“The rye greens up early and is pretty aggressive,” he says. That’s good for curbing early-season weed growth. He adds it tends to grow taller than winter wheat, which aids harvest.

“When you harvest over the top of soybeans, you don’t have to worry as much about damaging them,” he says.

However, early-season growth can overwhelm soybeans.

“Winter wheat gives me a little more time to plant [soybeans] in the spring,” he says. It also tends to outyield cereal rye, which helps garner more bushels to use as cover crop seed on his own farm, he adds.

Adams plants wheat in 15 inch-rows and returns in May to plant soybeans in 15-inch spacings between wheat rows. Seeding rates vary between 1 to 1.5 bushels per acre. At harvest, he moves the cutter bar closer on his combine’s bean head to be closer to the wheat heads.

“That way, we only cut off the top of the plant as the reel pushes the wheat into the head,” he says.

Relay cropping isn’t easy. In 2023, he harvested a field where soybeans grew nearly as tall as the wheat.

“I tried putting tile over my sickle, and it fell off,” he says. “Another challenge I had was that when I planted the soybeans into the wheat, they delayed the wheat’s maturity. Finally, I just threw my hands up.”

He left the wheat and harvested it with the soybeans. “We took the mix to local seed cleaner, and he separated the two,” he says. “I used the wheat seed to plant my cover crops the next year.”

Still, he continues undeterred.

“I’d encourage everybody to keep trying, because you’re always going to learn something,” Adams says. “If you don’t try, you have to wait another year before you get a chance to try again.”