Water Saturated Soil Conditions & Soybeans
- If not emerged, soybean stand can be significantly reduced after 48 hours of saturated conditions (anaerobic).
- If emerged, soybeans can withstand 2-4 days of submerged conditions depending on temp with varietal difference evident.
- If foliage is mud covered a rain to wash off the soil can be beneficial
- A few days after the water recedes, split the stem to examine the growing point and the taproot tip. Brownish or tan discoloration indicates damaged tissue.
- Water-logged soils favor the onset of diseases. Pythium if it is cold and Rhizoctonia and Phytophthora if is warm
- Replant decisions:
- 80,000 well-spaced plants can yield well in May, while higher populations are desired later.
- Even though conditions would likely be warmer, the need for seed treatment may be warranted due to the increased presence of soil-borne pathogens.
- Research from Purdue suggests that the yield potential of filling in thin soybean stands (below 66,000) is higher than tearing up the stand and starting over (Figure below)
- Filling in a thin stand can increase late-season soil shading, which has weed control benefits.
- Plants under stress are more affected by other stresses, so if a farmer chooses to keep those areas, PGRs, foliar nutrition & fungicides are even more critical.
- Add post herbicides that provide residual activity on weeds such as waterhemp. Palmer pigweed, cocklebur, fall panicum, and foxtail
A good resource from KSU: https://eupdate.agronomy.ksu.edu/article_new/soybean-response-to-standing-water-and-saturated-soils-334
A good resource from Purdue on soybean replant decisions: https://www.extension.purdue.edu/extmedia/SPS/SPS-104-W.pdf