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Posted 27 May 2014. PMN Crop News.

Severe Weather Doesn’t Always Mean Disaster With Corn

Source: Louisiana State University Press Release.

Winnsboro, Louisiana (May 20, 2014)--Corn has seen abundant growth in the past several weeks, but with the increasing temperatures, the number and severity of thunderstorms could cause some damage, according to LSU AgCenter scientists.


“Two major concerns with these increased thunderstorms for the corn crop are wind and hail damage,” said LSU AgCenter agronomist Josh Lofton.

With the current corn crop beginning to reach critical growth and developmental stages, people often wonder how much yield loss can be associated with these potential injuries, Lofton said.

While the answer seems somewhat straightforward, many factors determine how detrimental the injury will be and how much yield loss can be expected, he said.

It may appear that all wind damage is similar, said LSU AgCenter soil scientist Beatrix Haggard. “This is far from the truth. Root lodging appears as the entire stalk has been blown over at the ground level with the roots appearing to be dislodged from the soil surface.”

Given good growing conditions, the crop will reroot and continue to grow, she said.

Snapped corn is a more severe effect of wind damage – often referred to a green snap.

“This effect can be seen after the emergence of the growth point from the soil surface. However, it is more common during late-vegetative or early-reproductive growth when high biomass is paired with high winds. Unlike root lodging, it is unlikely a plant that has experienced green snap will recover from the injury,” LSU AgCenter corn specialist Dan Fromme said.

However, the overall effect on yield will vary based on how widespread the damage is and in what stage the crop was in when damage occurred.

“When snapped corn occurs during late-vegetative or early-reproductive stages, both the severity and the yield impact are often higher, with as much as 50 percent yield loss expected in severely damaged corn,” Fromme said.

Hail, in addition to rain and winds, can also be a damaging aspect, said Haggard.

“Hail damage can be very disheartening since the visual damage is often worse than it really is. It is best to not attempt to evaluate a hail-damaged field the day of or the day following the event,” she said.

Corn has an amazing ability to recover from damage, especially during early-season growth. Evaluation of these fields should be delayed until favorable growing conditions with adequate moisture have returned. This will allow the manager to determine which plants are growing and which are not, Lofton said.

“The primary loss of yield due to hail damage comes from loss of leaf area. However, determining leaf area damage can be a challenge,” Fromme said. “Two critical aspects in determining how this reduction in leaf area can influence yield are percent defoliation and growth stage in which the damage occurred.”