Editor’s Note: This is a draft of guidance being developed by the USDA Southeast Climate Hub to help soybean producers prepare for and recover from hurricane damage.
Post-hurricane recovering within a week following a hurricane:
#1. When safe, closely inspect fields where flooding has occurred.
Three to four days of continuous flooding can cause irreversible damage in soybean and subsequent yield declines. In addition to agronomic damage, flooded grain could be considered altered by your insurance company depending on flooded water source. Completely submerged pods have the potential for toxin contamination and some insurance policies may allow for zero appraisal following this situation.
This situation may require entry into nontraditional markets if grain is determined sellable.
#2. Check for disease.
Diseases will likely develop if the soybeans have been flooded for 3-4 days; sprouting in the pods is possible under these conditions. If your fields have been flooded with off-farm water sources, be aware of weed seed that could have been carried in that has not traditionally been a problem on your farm and be aware of the management implications from this in subsequent seasons.
#3. Document damage with photographs to assist with insurance recovery purposes.
Remember that “a picture is worth a thousand words.”
#4. Check with your crop insurance agent.
It is important to check with your crop insurance adjuster as quickly as possible to decide on the best plan moving forward with your potentially damaged soybean crop.
#5. Take into account growth stages.
If soybeans are still between R3 (beginning pod) and R5 (beginning seed) and you can safely enter the field, a fungicide application may be warranted and could help prevent seed quality issues.
Leaf diseases (frogeye leaf spot, rust, cercospora blight, brown spot and others) and root rots (phytophthora and pythium) will likely be more severe after excessive rain and flooding.
Fungicides applied for seed decay organisms, including phomopsis seed decay, may reduce damages to seeds between R3 and R5, but will not likely impact yield.
#6. Scout soybean for lodging.
Soybean lodging can be caused by strong winds and by water flow across the field. The effect of lodging on soybean yield varies, but soybeans in the beginning seed stage (R5) will likely be more prone to damage from lodging than soybean that are further into physiological development.
There are two types of yield losses associated with lodging – restriction of maximum physiological development and harvest loss. Restriction of maximum physiological development can occur from lodging reducing photosynthesis in the upper, more productive leaves. Harvest loss from lodging can range from 3-10% (Holshouser, 2015).
Slowing down the combine and harvesting in the opposite direction of the lodging may reduce harvest losses from lodged soybeans. Lodging is more likely with higher-yielding soybeans.
#7 Check soybean for maturity.
Flooding of soybeans will likely lead to premature defoliation that can speed up maturity. Be ready to harvest mature soybean when field conditions allow. Within a Month Following Hurricane Impacts
#8. Check soybean for quality declines.
Develop a selling plan accordingly. Soybeans that have been under flooded conditions for several days have an increased risk of being contaminated by things such as diseases and mycotoxins caused by disease.
Excessive rainfall can cause pod splitting. This is especially problematic if the rain followed a dry spell. When soybeans are at R6 (full seed) or R7 (physiological maturity) and receive excessive rain, rapid seed growth can trigger pod splitting, especially when pods are small due to earlier season stressors.
Premature seed sprouting is generally rare but can be an issue when the moisture of the seed drops below 50%, but then goes back above 50%.
#9. Scout fields for soybean shattering.
Shattering intensifies when dry pods are rehydrated by excessive moisture followed again by a dry period. Shattering losses can be more severe with earlier maturing varieties that are close to physiological maturity and are ready for harvest.
Unfortunately, the flooded conditions may restrict field access in some areas, and this delayed harvest can intensify shattering. If you have a field where harvest shatter is a problem, harvest that field as early as possible. Start earlier is the day when the plant material still has some moisture. Reducing combine speed may all reduce losses from shatter.
AgFax Weed Solutions
If growers have fields where significant shatter has occurred, they should be prepared to manage soybean regrowth the following year by rotating to production of a different crop in that field where soybean regrowth could be terminated through another herbicide chemistry.
If rotating to a different crop is not possible, the soybean herbicide trait package should be rotated or the grower should plan to plant the next crop of soybean after regrowth of the shattered soybean has occurred (this can be difficult to predict) and can be terminated via herbicide application.
#10. Devise an alternative storage plan for damaged soybeans.
If you have a diversity of soybean maturity groups and varieties planted on your farm, chances are you will have differing levels of soybean damage among your fields. Field to field damage will also vary depending on proximity to flooded water sources.
If possible damaged grain should be stored separately for undamaged or minimally damaged grain to ensure high-quality grain can be sold without dockage.
#11. Sample ahead.
Take a soybean sample to the elevator or buying point to assess damage and determine if selling is an option. This can prevent you from paying the freight cost to move soybeans to the buying point if ultimately they will not be purchased.
#12. Investigate soybean marketing options.
Excellent resources are available on marketing flooded grain after Hurricane Florence from Dr. Nick Piggott.
#13. Soil sample ASAP.
Once flood-waters have receded, soil sample your fields to understand fertility impacts. Both flooding and excessive rainfall can lead to nutrient leaching and limit subsequent nutrient availability.
Soil samples should be taken following a hurricane to ensure correct fertilization of hurricane-affected fields in the following season.
This draft guidance (see full report here) was developed by subject matter experts from North Carolina State University Extension Services (Rachel Vann, Wes Everman, Anders Huseth, Dominic Reisig, Lindsey Thiessen) and Virginia Tech Extension Services (David Holshouser).