Jarrod O. Miller, Extension Agronomist,
While Hurricane Erin stayed off our coastline, there were several days of flooding, surges, and high tides that may have deposited salts outside of typical parts of the field. Whether from tidal creeks, the Delaware Bay, or Atlantic Ocean, these waters are high in cations (sodium, magnesium, calcium) and anions (bicarbonate, boron, sulfate, and chloride). Excess levels will cause crop death and nutrient imbalances. Just a few days of high tides in this field (Figure 1) have already affected a soybean crop.
A recent factsheet outlines potential Na levels that may reduce crop yield (http://www.udel.edu/0013776), with higher levels leading to death. For corn, 340 ppm Na may begin to reduce crop growth, while soybean should be able to tolerate up to 1000 ppm Na. However, this is based on western dryland research, and soybean may also see reduced crop growth at similar Na levels to corn, as this also indicates saturated soils, poor drainage, and higher levels of other salts. Be sure to check where crops may have been affected and take soil samples and contact us for any questions.
Figure 1. The white line shows where tidal flooding has already damaged soybean. It follows closely with elevation in these fields, where storm surges pushed saltwater into the fields.