Whether planting soybeans late or double-cropping soybeans early, management is similar. Here are five tips to consider adopting:
- Plant as soon as the soil is fit or immediately after wheat harvest into fit soil
- Narrow-up rows if possible
- Increase seeding population by 20 to 30 percent
- Plant a full season variety that performs
- Continue using seed treatments
Some years planting full season soybeans seems to merge with the trend to plant double-crop soybeans and there seems to be little gap in between. This year, full season soybean planting or replanting came right up against double-crop planting. With later planting, important management strategies come into play.
Narrow rows are more important as the planting date gets later. More plants are needed to close over the row, capture more sunlight and set more pod-bearing nodes. While 130,000 to 150,000 plants per acre are adequate for full season seeding with May planting (and on the lower side in April), this should be increased to around 160,000 to 180,000 for the first half of June and 180,000 to 200,000 when planting the second half of June or later.
Research is beginning to show that seed treatments are just as important for double-cropped soybeans as for full season soybeans. Remember, soybeans are being seeded into harsher soil conditions with uncertain moisture and possible delays in emergence. Protecting that seed is crucial to give it the best opportunity to survive until emergence and establishment.
The old rule of thumb is that soybean yield potentially drops an average of 0.5 bushel per day when planting after May 15 and a bushel a day after June 1. Planting soybeans earlier is critical when double-cropping. If you’re a wheat grower and plant soybeans afterwards, consider harvesting wheat at a higher moisture content and drying it for better test weight to get a jump on planting soybeans. Each day planted earlier is an additional bushel of yield. For soybeans planted in June, choose varieties in late Group 3 or early Group 4.
Generally, the rule of thumb for planting in early July has been to back variety maturity off to a mid-Group 3. If planting even later, drop down to an early Group 3. However, some recent research has shown that one should extend the maturity group of the soybeans by a half to a full maturity group. The reasoning is that soybean maturity is truncated (shortened) the later it is planted. Shorter maturity means plants could mature too quickly and give up yield.
Soybean agronomist Daniel Davidson, Ph.D. posts blogs on agronomy-related topics. Feel free to contact him at firstname.lastname@example.org or ring him at 402-649-5919.