Step No. 1: Do not panic — give crops time to recover.
You’ve heard about the calm before the storm. What about the calm after the storm? Anyone who has experienced a hailstorm ravaging their fields knows that immediately following the event, there is no calm. Agronomists say that is the wrong time to make decisions.
“We suggest waiting five to 10 days before assessing the likely final outcome,” explains Mark Licht, Extension cropping specialist for corn and soybeans at Iowa State University. “Give the crop time to recover. In many cases, regrowth will occur. Immediately after the storm, it can be difficult to determine which plants will survive.”
When the storm occurs may affect how long you can wait. If replanting is still an option, there is some urgency.
“Weather conditions in the days following the storm are a big factor,” Licht adds. “If it is sunny, 90 degrees F and sweltering, it may be different than if conditions are cool and overcast.”
Stand reduction
In Nebraska, Justin McMechan, crop protection and cropping systems specialist, says assessing the soybean crop’s ability to recover comes down to two key factors.
“You must assess stand reduction caused by the storm, and then plant damage,” he says. “It will often be at least six days before regrowth occurs so you can make those assessments accurately.
“The important thing [at that point] is to determine remaining viable stand. If you have 90,000 plants per acre remaining, you’re going to be OK. Even at 60,000, the potential yield loss compared to a full stand may only be around 20%.”
Compare remaining stand to the original stand to determine how much yield loss may be attributed to stand reduction alone. Evaluating Hail Damage to Soybeans, UNL Bulletin EC128, contains tables and a worksheet to assist in computing potential yield loss.
Plant damage
“Even if stems are bruised, plants can recover if buds are still alive,” ISU’s Licht explains. “Often you will see more branching after hail. If buds are alive, they can send out branches.”
Stage of growth greatly influences plant damage and ability to recover. Both Licht and McMechan recommend referring to Soybean Growth and Development, PM 1945 for help on staging soybean growth correctly.
The next step is determining percent defoliation, McMechan notes. “Defoliation often looks worse than it is,” he says. “Do your best to determine amount of leaf area destroyed. Compare that to your estimate of leaf area before the storm.”
Refer to defoliation tables in UNL’s EC128 to determine percent of leaf area destroyed. Couple this information with stand reduction numbers to determine overall estimated loss.
Source: https://www.farmprogress.com/soybean/how-to-assess-hail-damage-in-soybeans
