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Source: Farm Progress
Grain harvest is underway in many areas, with others soon to follow. Where possible, soybeans may be planted as a double crop; however, some considerations should be made. Double crop soybean production is not the same as full season production. This article discusses main points to consider.
Harvesting & Storage of Grain
Harvesting grain early allows us to get our soybeans in the ground sooner. Every day of delayed planting matters with double crop soybeans, so you may consider harvesting wheat at a higher moisture, (~20%) if you have the ability to dry it. Earlier harvest may also result in higher quality wheat, because you can avoid the wet/dry cycles of repeated rain events, which takes a toll on grain quality.
Soybean Variety Selection
Select a soybean variety with a little later RM than your earlier full-season plantings. This will allow for a longer vegetative growth period, with potentially more nodes, flowers and pods set. Increase your seeding rate by 10-15% from full season rate and add to that ~10% weekly as the calendar moves along in your geography. Spacing is also important, as double crop soybeans are not likely to fill out as much as our full season varieties. Double crop soybeans should be planted in narrow rows (7.5” – 15” ). This broader plant distribution allows for more sunlight exposure per plant, resulting in higher yields, less weed pressure, and better soil moisture retention.
Weed Control
Start clean, with a good burndown program and with pre-mergence herbicides required per anticipated weed spectrum. Remember to check herbicide crop rotation restrictions in consideration of next season’s crop.
Insects
Late planted soybeans may be susceptible to a greater variety of insects as they may move from other more mature crops to the young soybeans. Double cropped soybeans also will be smaller, and less able to compensate for losses due to insect feeding. Consequently, defoliators such as bean leaf beetles and Japanese beetles may cause more relative damage to the less vegetative double crop, compared to full season soybeans.
Diseases
Double cropped soybeans do not typically have as many disease issues as full season soybeans unless they are produced under irrigation or the season is abnormally wet. The shorter growth period, smaller canopies, and hotter temperatures is unfavorable for foliar and stem disease development in many cases. Nematodes have less time to build populations as well, reducing potential impact.
For more information, contact your local FS Crop Specialist.