Scouting soybeans after a cool wet spring
If you’re fortunate to be done with planting your crops, it’s time to get back out there and check your stands. This year I’m especially concerned with soybean stands for three main reasons:
- Cold soils. Many fields were planted when soil temperatures were below the recommended 60° Fahrenheit. (This link goes into more detail about the importance of soil temperatures: https://bit.ly/2JuHTkO) Cool, wet conditions can lead to severe disease infestation and reduced stands. Seed treatments protect the seedlings before and just after emergence. Historical data shows that not using a seed treatment can cause yield loss of 2½ to 3 bushels per acre if damping off occurs, but many farmers cut back on seed treatments this season to lower their input costs.
- Wet soils. Farmers felt like they were racing against the calendar during an especially wet spring, so some seed was planted into unfit soils. Planting into wet soils can lead to both sidewall and overall field compaction. Delayed emergence may cause uneven stands and reduce yield. Nutrient deficiency, reduced crop productivity and restricted root development are three of the top 10 reasons to avoid compaction. (Click here for the rest of the story: https://bit.ly/2VS06zo)
- Soybean Gall Midge. This new insect pest was especially damaging last season in Northeast Nebraska, Northwest Iowa, Southeast South Dakota and Southwest Minnesota. Ask your local Extension Agronomist if any of these pests have been reported in your area. (You can learn more about Soybean Gall Midge in this blog post: https://bit.ly/2JSLetw)
Walking fields right after emergence gives you the most time to make corrections or to replant. Stand reductions rarely occur evenly across a field. That’s why I recommend taking 10 stand counts in the area where the problem is the worst, as well as taking 10 counts in an area that was not affected or is slightly affected. Most university researchers recommend keeping a final stand of at least 100,000 plants per acre.
University trials also indicate that planting soybeans on or before June 1 in northern Iowa and southern Minnesota gives 95% of expected yield. It is usually June 15 before soybean yields drop below 85% of what is expected. Over the years, we have seen decent soybean yields when soybeans were planted around the 4th of July.
Scouting early and often is the best advice I can give, so you can remedy the situation as soon as possible. Different insects, diseases and pests may be present due to weather conditions and stage of crop development. Scout diligently all growing season long!