Ohio’s corn crop starting to get thirsty


COLUMBUS – With seedling blight diseases and replanting issues out of the way, Ohio corn growers are now faced with a new challenge: inadequate rainfall.
Peter Thomison, an Ohio State University Extension agronomist, said that lack of rain across the state is the biggest problem growers are facing, and if the dry weather pattern doesn’t change, yields could be impacted.
Corn OK, for now. “Corn, by and large, handles dry weather fairly well, but it’s extremely vulnerable during the pollination period,” said Thomison.
“Corn now doesn’t look too bad, but if we have hot, dry weather into July, then we may be looking at poor kernel set, reduced ear size and reduced kernel weight. That all hurts yield potential.”
Corn is anywhere from the V-5 to V-9 stage of development (where five to nine leaf collars are visible on the plant), and the crop, overall, is holding its own.
However, corn in some fields is already showing signs of stress with a condition known as “leaf rolling.”
Defending itself. “It’s a defense mechanism. The plant is shutting down to prevent loss of moisture, but by doing so, it’s not photosynthesizing,” said Thomison. “It’s not creating sugars for the plant to actively grow. The result could be stunted plants later in the season.”
Thomison said that some of the stress on the corn crop is due to an underdeveloped root system from replanted plants that were quickly subjected to dry weather.
Because of the poor root system, moisture is evaporating faster from the plants than they can keep stored. Additionally, much of the earlier planted corn is also suffering due to the dry weather.
Precipitation across Ohio has been below normal for this time of year, nearly 2 inches below average since April.
Double trouble. Couple that with higher than normal daily temperatures and a decline in the number of growing degree days (24 days below average), and growers are resigned to sit back and see what happens.
“If we can get normal rainfall and mild conditions during grain filling, we could still end up with an average to above-average corn crop,” said Thomison.
Stages. The corn crop is currently in a stage of development where the girth of the ear is being determined. The outcome of kernel development won’t be evident until the end of July or beginning of August when the plant enters the pollination period.

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