By Alexander Lindsey and Laura Lindsey et.al
A large portion of Ohio received substantial rain and scattered storms over the last week, resulting in waterlogged or flooded conditions in fields (Figure 1). Corn and soybean fields are mostly in the grain-filling stages, and the yield impacts of flooding will likely differ for each crop.
Soybeans are not very tolerant of flooding during the reproductive stages. Available literature has shown that a flood duration of 4 days or greater during reproductive stages (R2-R5) can result in significant yield loss (25% to 85%). Additionally, there is a wide range in varietal tolerance to flooding for soybeans, so every variety may not be impacted the same. Much of the yield penalty will likely be related to how long these fields stay flooded (or saturated). Corn yield losses from flooding during grain fill stages tend to be much lower, with yield losses being 5-7% for flooding up to 3 days, or around 15% if flooding lasts for 6-7 days at the R1-R2 growth stage. We are well past this stage in much of the state, so it is possible yield losses will be similar to or less than the values provided here for corn. Be sure to keep an eye on your fields to see how quickly the flooding or saturated conditions remain as this will likely affect the magnitude of any potential yield loss.
Corn fields may have experienced some lodging or greensnap with strong storms. Root lodging during the reproductive stages (R2-R4) can be detrimental to yield, with yield losses expected to range from 15-35%. The larger issue that lodged plants will be challenging to harvest, and attachments like a reel or spiral cone to the header may be needed to help collect the ears from downed plants. The grain quality from lodged plants may also be lower due to less air movement and closer to moist soil, which could create an environment conducive to ear disease development. If plants have bent or snapped, yield losses may also be incurred. In past estimates, stem buckling during the reproductive stages has caused 15-20% yield loss, and for every 1% of plants that greensnapped (full stalk breakage below the ear), a 0.5-1.0% loss in yield can be expected. Damage from wind due to lodging or greensnap may be covered by crop insurance policies to help offset damage from the storms. If you have crop insurance, we recommend you talk to your agents.
Source : osu.edu