The Ulster Farmers Union has called on the Department of Agriculture to offer workshops advising on alternatives, amid claims of a propionic acid shortage.
The apparent shortage in supply has been caused by delivery problems at two of the largest global manufacturers, Force Majeur and one other.
German additive firm ADDCON warned price rises could be on the way. It also warned of delivery problems with formic acid, which is used in animal feed and silage production.
Propionic acid is often used as a seed treatment for grain to protect it from mould.
Alternative measures include drying grain prior to storage. However, this can be expensive and difficult for growers who do not own a dryer.
'Growers will need to act quickly'
UFU deputy president William Irvine said: “After being made aware of the issue and recognising that some suppliers are having problems sourcing propionic acid, with suggestions that these difficulties will continue into the foreseeable future, arable growers will need to act quickly and consider all alternatives.
“We are encouraging arable growers to contact their local supplier immediately to inquire if they have stock in-hand and if not, to actively explore other alternatives on the market. Northern Ireland merchants are actively doing all they can to try to identify and source alternative grain preservation products for growers.
“The situation has arisen due to serious supply challenges on the world market, and this has the potential to impact some local merchants and farm businesses.
"Whilst this is not Brexit related, the message remains the same: Growers must plan ahead and make it a priority to speak with their local suppliers as a few may still have propionic acid in stock and it will now be in high demand for harvest 2021.
“We will continue to monitor the situation closely and have requested for CAFRE to assist and consider delivering workshops on alternative options to help those farm businesses unable to secure a supply of propionic acid.”