Double The Crop, Double The Potential

 

 

If you planned for a double-crop soybean system this season, harvest of your small grain crop and planting of your double-crop soybeans are right around the corner. Virginia Tech University Extension Agronomist David Holshouser, Ph.D., shares his advice for planting and managing your double-crop soybeans this season for higher yields.

 

 

The shorter time allotted for full plant growth and development is a risk commonly associated with double-crop soybeans. It’s critical to plant your double-crop soybeans as early as possible. But in order to do so, you must have an early wheat harvest. Planting ultra-early wheat varieties that mature earlier than conventional varieties, and harvesting wheat at 18-20% moisture can allow farmers to plant soybeans up to 14 days earlier. Holshouser says even if the early wheat does not yield quite as well, the extra soybean yield gained from planting earlier will make up for the loss.

 

“On average, we lose about a half-bushel of soybeans for every day we delay planting after mid-June,” says Holshouser. “Ideally, it’s best to plant your soybeans the exact same day that you harvest your small grain crop, to allow for as much time in the field as possible. Generally, the earlier you plant, the higher the yields.”

 

Though having a same-day harvest-plant strategy for double-cropping is ideal, sometimes low soil moisture can alter that plan. If the soil is too dry, Holshouser suggests either waiting to plant your soybeans until the next rain or planting deeper to try and hit moisture housed below the top two inches of soil.

 

Finally, Holshouser says planting in narrow rows is a must for double-crop soybeans. Narrowing the rows will result in greater leaf area and more sunlight capture than wider row spacing, allowing for faster plant growth.

 

 

Just as in full-season soybeans, double-crop soybeans face threats from weeds, insects and diseases. Thanks to crop residues, herbicides and minimal soil disturbance provided by the small grain crop, however, management of weeds may be less intensive.

 

“The herbicides used for weed-control in wheat help our double-crop soybeans tremendously,” says Holshouser. “Having a weed-free wheat field will likely lead you to a weed-free soybean field.”

 

But don’t rely solely on help from small-grain residue for help with weed control.

 

“Include residual herbicides into burndown and/or postemergence herbicide applications to avoid herbicide resistance,” says Holshouser. “Due to faster weed growth, resistant weeds can be more of a problem in double-crop soybeans, and farmers must take precautions early.”

 

Regular scouting for insects and diseases are also a priority for double-crop soybeans. Depending on your region, insect populations and disease threats can be greater later in the season, potentially posing as a threat to your late-planted soybeans.

 

If an insecticide application is necessary, Holshouser says to ensure it’s based on the established economic thresholds. Likewise, if the likelihood of disease is high, use a foliar fungicide containing at least two modes of action.