Double cropping soybeans after wheat is a common practice in many states, from Kansas to Maryland and south to the Gulf of Mexico.
We typically think of this rotation being planted south of Interstate 70 in the U.S. Pushing the rotation further north puts soybeans at risk of frost damage and reduces the opportunity to make a profit on soybeans.
So it was something of a surprise to learn Ontario growers are successfully planting soybeans after peas (an early vegetable), barley or wheat and that both crops in the rotation are profitable.
Syngenta agronomist Eric Richter works with Ontario growers who double crop soybeans after wheat. “Wheat yields are running from 95 to 105 bushels followed by soybean yields between 30 and 40 bushels, while our full-season soybeans yield from 40 to 50 bushels.”
Ian Matheson, a producer from Embro, Ontario, has been double cropping soybeans after barley for 15 years. “For us it is important to plant soybeans after barley because we can plant soybeans two weeks earlier than after wheat.” He said barley yields average 100 bushels per acre (bpa) or greater and his double-crop soybeans typically yield 25 to 30 bpa. However, his double-crop beans came in at a 42 bpa average in 2015.
Horst Bohner, provincial soybean specialist with the Ontario Ministry of Agriculture, Food and Rural Affairs, said the latitude and climate in southern Ontario, along the Great Lakes, extends the fall growing season so soybeans can mature. Richter added, “In the northern half of Ontario, the heat units go down enough that wheat is harvested too late, not leaving enough heat units for soybeans to mature. However, planting barley and ultra-early soybeans still presents a good opportunity.”
Double cropping takes better management and attention to detail. “They (growers) need to plan ahead for this rotation. They can’t play it by ear as that isn’t a recipe for success. Double cropping is not a system for everyone,” Bohner said.
Variety choice is critical and Bohner credits new varieties developed especially for the Prairie provinces for much of the surge in double crop interest. He said many of the new Group 00 and 000 are capable of producing 40 bpa.
Bohner said soybeans should be planted by July 10 for best results. That means managing the cereal crop for early harvest. In some cases, this means harvesting wheat early and drying. Peas and barley tend to come off earlier than wheat in this area.
Richter recommends increasing double-crop soybean seeding rates to 250,000 to 300,000 seeds per acre in the heaviest soils. Ontario growers drill beans in narrow, 7.5-inch spaced rows. “It is important to plant at high populations to get more nodes per acre and close the soybean canopy quickly since soybeans only grow thigh high,” Richter said.
Dry soils in July are a threat to soybean germination for any double-crop producer. Matheson always plants into moisture. “The soil is warm and we plant below 2 inches to hit moisture in case we don’t see a rain for a few weeks,” he said.
Richter offers these tips to growers in Ontario who want to double crop:
- Have a plan in place and be a good manager.
- Confirm you have sufficient heat units to mature the soybean variety.
- Choose the right first crop that will be harvested early enough to plant back to soybeans.
- Choose a soybean variety that performs in double-crop rotations.
- Drill, don’t plant with a row planter, at 250,000 seeds per acre or higher.
- Apply all the same best management practices as full season soybeans.