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Soybean Replant Considerations

Soybeans are prone to poor plant establishment because the seedling must pull the cotyledon seed leaves through the ground to emerge. Plant stand reductions are rarely uniform, which makes the decision to replant difficult. Do not assess a poor soybean stand too quickly, since more seedlings may still emerge. In 2020 we have seen soybeans emerge 40 days after planting. Amazingly, many April planted soybeans that suffered from extreme cold now have excellent plant stands. Often once a crack is visible on the soil surface down the row a sufficient number of seedlings will survive.
 
A plant reduction of up to 50% does not need replanting if plant loss is uniform and the stand is healthy. Numerous studies and field experience have demonstrated that keeping an existing stand is often more profitable than replanting. Replanting gives no guarantee of a perfect stand. Keep in mind that normal seeding rates include a margin of safety to ensure emergence of an adequate stand.
 
Understanding the cause of the low plant population is essential to know if replanting is necessary. These include soil crusting, herbicide injury, frost, hail, insects and diseases. For instance, if seed corn maggot has reduced the stand many of the surviving seedlings will also be partially destroyed. Replanting in that case is usually the correct decision because the remaining plants are also weakened, and an insecticide seed treatment is necessary when replanting. In a wet year, damping-off may be the issue. In this situation consider the use of a variety resistant to Phytophthora plus a fungicide seed treatment when replanting.
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