Uncovering Hidden Revenue

BY MATTHEW WILDE

Dean Sponheim and other Iowa farmers will plant soybeans into narrow strips of tilled soil surrounded by corn stalks this spring.

Strip-tilling soybeans isn’t for everyone or every farm, soil and agronomy experts say, but research data and on-farm results show it can boost yields and revenue.

For strip-till veterans, especially those with heavy, black soil, they're sold on the practice. It’s an opportunity to reap the benefits of tillage while protecting and improving the soil — all with the bottom line in mind.

“I can plant earlier, get a little yield bump and prevent soil erosion like this year when we got 55 inches of rain,” says Sponheim, an Iowa Soybean Association (ISA) member from Osage.

Dean Sponheim stands in one of his fields near Osage.

Joseph L. Murphy/Iowa Soybean Association

Scott Nelson, ISA On-Farm Network® director, says tough economic times — cash soybeans dipped to 10-year lows in November at about $8 per bushel — dictate that producers evaluate every agronomic decision. That includes tillage or the lack of it.

Strip-till is a system in which residue-free strips of soil about 6 to 8 inches wide (about one-third of a row) and 4 to 8 inches deep are tilled ahead of planting using a knife apparatus such as a fertilizer injection shank. It’s widely used in corn production statewide, but less so for soybeans.

Whether a farmer is a diehard no-tiller, favors conventional tillage or something in between, Nelson says strip-till may be an option.

“Investing money and time in tillage is an important decision in soybean production,” Nelson says. “I’m still a big proponent for no-tilling soybeans, but every input should be scrutinized for overall effect on per bushel production costs.”

A dozen On-Farm Network replicated strip trials were conducted this year, mostly in the northwest part of the state, comparing strip-till to no-till and conventional tillage in soybean production. Results weren’t available at press time.

Strip-till had a $10.40-per-acre advantage over no-till based on limited past trial results, according to the On-Farm Network's return-on-investment calculator. A soybean market price of $8 per bushel and ISU’s average custom strip-till rate of $19.20 per acre were used.

According to Iowa State University (ISU) and ISA experts, the following are agronomic advantages of strip-till that could boost yields and revenue:

• The seed zone warms and dries quicker in the spring compared to no-till. The odds of earlier planting increase, especially in central and northern Iowa.

• Plants germinate quicker and emergence is more uniform compared to no-till.

• Higher stand counts could occur.

• Strip-tillage is cheaper than conventional tillage. For farmers doing their own work, ISU data shows striptill costs $15 per acre compared to $30 per acre for conventional tillage.

• Nutrients, such as phosphorus and potassium, can be banded near the root zone during the strip-till pass.

• If strip-tilling is done in the spring, it can wipe out some seedling weeds.

Planting soybeans into narrow, tilled strips could boost yields and revenue compared to no-till production. Studies are ongoing to compare the two practices.

Joseph L. Murphy/Iowa Soybean Association

“Strip-till provides a happy medium to no-till and conventional-till by preparing a seed bed without burying all the residue,” says Rich Stessman, ISA On-Farm Network operations manager. “Farmers can have the best of both worlds.”

ISA District 1 Director Chuck White is checking that out for himself.

The Spencer farmer has strippedtilled corn for 15 years and no-tilled soybeans since 2004. He’s a staunch believer in both production practices.

But white mold is curtailing soybean yields, White says. To combat the disease, he switched from narrow to 30-inch rows in 2018. However, research shows 30-inch rows typically yield a few bushels less per acre than rows half as wide.

White enrolled 150 acres of soybeans last year in an On-Farm Network-replicated strip trial comparing strip-till to no-till to see if yield and revenue losses could be mitigated. The jury is still out, he says.

The entire trial field fertilized with chicken manure averaged 61 bushels per acre, but data is still being crunched by ISA experts. An extremely wet year caused uneven stands, which will likely skew results, White says. He plans to participate in more soybean tillage trials this year.

“I want to see if there is an advantage with strip-tilling by incorporating some of the chicken litter,” White says. “Plus, I know striptill acres in northern Iowa have an advantage because the soil warms up faster compared to no-till.

“That practice was really working well, but I’m willing to try anything to increase revenue and improve soil health,” he adds. “If I can do it with less tillage I’m happier. But if I can increase yields, I’m all for it.”

ISU recently released 14 years of data studying five tillage systems, including strip-till. Mahdi Al-Kaisi, a professor of soil management and the environment, said there’s no significant yield difference between different tillage practices.

In low moisture years, though, strip-till out yielded conventional till by 2-3 bushels per acre. Strip-till typically yielded 2-3 bushels more per acre compared to no-till.

“There are a lot of advantages with strip-till,” Al-Kaisi says.

There are also disadvantages, like the initial cost. Sponheim says a new 12-row, strip-till rig with fertilizer distribution costs $90,000 to $120,000, and it takes a high horsepower tractor to pull it.

Strip-till isn’t recommended on steep slopes or where contour farming is done due to erosion concerns.

Sponheim has strip-tilled soybeans for himself and other farmers for six years. He says there’s an economic return.

“In most years, the yield boost is a couple of bushels per acre,” he added. “One guy claimed a 10-bushel difference.”

Contact Ann Clinton at aclinton@iasoybeans.com.