Research Highlights

Research Highlights
Testing the Viability of Double-Cropping and Intercropping of Wisconsin Soybeans

The soybean–wheat intercropping study in Wisconsin included comparison of no-till and strip-tillage. The soybeans will be planted in the tilled strips in between the established wheat crop. Photo: Shawn Conley

By Carol Brown

Harvesting sunlight and heat to make the most of what’s growing in a field might be a way to increase farmer profitability. Double-cropping or intercropping makes the most of sun and heat in one growing season. But can farmers improve their bottom line with these cropping systems? Shawn Conley is looking into their potential for greater yield or profit on Wisconsin farms.

Conley, the Wisconsin state soybean and wheat extension specialist, is exploring intercropping and double-cropping with soybeans and winter wheat through a project supported by the Wisconsin Soybean Marketing Board. 

“In general, farmers are planting earlier to capture the free yield associated with this management change,” Conley says. “This gives them a wider window to capture both light and heat. And the USDA Risk Management Authority has revamped a lot of crop insurance recommendations for many crops. For example, they’ve moved the date up for planting coverage, which is now April 15 in southern Wisconsin.”

To harness more of the available heat and sunlight, farmers might venture into double-cropping or intercropping. Intercropping is having two cash crops growing in the same field at the same time in alternating rows. Double-cropping is growing two crops, one after the other, in the same field in one growing season. 

Shawn Conley’s double-cropping study looked at soybeans planted immediately after wheat harvest. The team planted soybeans on July 22 in maturity groups ranging from 0.5–2.5. 

Conley and his team have conducted two studies looking at soybean yield by planting date and with no-till or strip-tillage in an intercropped system. They also conducted a double-crop study, planting soybeans immediately after wheat harvest. The team compared these systems to soybeans and wheat grown alone (a monocrop). They also performed a net return study to compare the profitability of intercropped wheat and soybeans to their monocrop counterparts.

“As cropping systems get more complicated, there are more places where things can go wrong,” explains Conley. “There are things that need fine-tuning with the intercropping system. Equipment needs modification; herbicides and fungicides are limited by type and application because of the two crops growing at the same time. One of the reasons we do research is to figure out the bigger obstacles and help farmers learn what to expect.” 

The 2022 season was the first year of this study. The team observed good, consistent wheat yields across all the scenarios, but they saw a yield loss in intercropped soybeans when compared the monocrop plots. They saw higher yields in the intercropped strip-tilled soybeans than the no-till plots, but the monocrop soybeans had much higher yields in both no-till and strip-till acres. 

The net return study that Conley and his team conducted painted a different picture. When considering market prices for both wheat and soybeans, the revenue from both crops makes up for the yield loss – but only when markets for soybeans are lower. 

“The intercropped system could work well if wheat prices are coupled with low to moderate soybean prices,” he comments. “That’s the niche where this system would fit best. But when soybeans are around $14, it difficult to give up any yield in an intercropped system.”

Figure 1. Comparison of Net Returns – Intercrop vs. Monocrop

The team hopes to conduct these experiments again in the 2023 crop year, with a few modifications. 

“We are adding a new treatment this year in the intercropping study where we’re not planting wheat in some strips, basically skipping a row, and then we’ll plant soybeans in those barren strips,” explains Conley. “It’s like having unplanted wheat strips on a 30-inch center. This will give the soybeans more room for canopy growth and enable the ease of harvest.”

They will also modify the wheat head on the combine, adding a bar to push down the soybean tops during wheat harvest. The tops of the soybean plants should pop back up after the combine passes through the rows. This modification will reduce the chance of clipping the top trifoliate soybean leaves and lessen the impact on plant growth. 

They will also conduct a soybean maturity group study and test seeding rates in a wheat double-crop system. The team intends to find the longest maturity group that could be used with this system to utilize those sunlight hours and heat units. They conducted this study in 2022, but early cold weather halted the soybean growing process before they could collect data.

“Farmers are pretty good engineers and can figure out the finer details, “says Conley. “If they have a good idea on future markets and have the equipment, these systems could be something to explore.”

For more information about this project, go to the University of Wisconsin Extension Cool Bean website:

Shawn Conley profile

Published: Mar 13, 2023