Shawn P. Conley, Soybean and Small Grains Specialist, UW-Madison
Early in the growing season, abiotic (freezing temperatures, hail, flooding, etc.) and biotic (slugs, deer, disease, insects, etc.) factors often reduce soybean plant stands. A soybean field with poor seedling vigor, slow plant growth, and low plant stand often triggers an “I need to fix this” impulse. However, these fields don’t always need to be replanted. This fact sheet addresses some commonly asked questions to consider prior to replanting a soybean field.
AT WHAT PLANT STAND DO WE NEED TO CONSIDER ACTION?
Soybean plants have a remarkable ability to compensate for open spaces by developing axillary branches that set additional pods. These axillary branches allow the plant to close open spaces and yield two or three times as much as plants that are crowded from normal planting populations (Suhre et al. 2014). With low final stand counts, it is common to have gaps larger than a square foot. Soybean plants will not be able to completely fill in these gaps which will result in yield reduction.
Action 1: Even minor stand loss warrants going across fields to assess the amount and pattern of plant loss.
Action 2: Stand loss that leaves fewer than 50,000 to 60,000 evenly- distributed plants per acre in southern regions, or 75,000 plants per acre in the most northern growing regions, or stand loss patterns that leave areas of more that 6 to 10 square feet in size without any plants, should be considered for replant.
Factors for evaluating whether to replant are:
- The existing plant stand, distribution of the plants, and their ability to recover full growth;
- Calendar date (effect of delayed planting and relative maturity);
- Weed management situation;
- Seed and variety availability;
- Cost to replant and insurance availability;
- Trade off: suboptimal stand vs. yield penalty to delayed replanting.
For more information >>>
https://soybeanresearchinfo.com/wp-content/uploads/2023/02/20230125_Factsheet_Replant_V2.pdf
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