Soybean Harvest Aid/Desiccation

BY Dairyland Seed Agronomy Team

In several areas of the Dairyland Seed footprint, soybeans have had a rough season. Obstacles such as uneven emergence due to varying soil moisture and drought stress which caused heavy weed pressure have been topics of discussion. These situations can lead to issues at harvest.

With delayed or uneven emergence, we can see uneven senescence, or ripening of soybeans, which can delay harvest and allow for early senescing soybeans to become too dry by the time the later senescing soybeans are ready for harvest. Heavy weed pressure can impact the harvestability of soybeans. As the soybeans senesce, the weeds can stay green. The added green vegetation is hard for combines to cut and process. Each of these situations could benefit from a harvest aid or desiccation. The application of herbicide or salt to defoliate later to senesce soybeans or terminate weeds in fields with heavy weed pressure.

Application Timing:

Uneven senescence or ripening (Desiccation): Applications of a desiccant should be made when the latest senescing soybeans are at least R6.5 (see definition with picture).
Heavy weed pressure (Harvest Aid): Applications can be made to the field any time after the soybeans reach R6.5 (see definition with picture).
R6.5 timing is important because the soybean is no longer attached to the plant and the seeds will begin to mature normally regardless of the condition of the plant foliage. Application of a desiccant or harvest aid before this stage can impact seed size and maturation.