Updated with news that Yara won't raise its bid for Terra.CALGARY, Alberta ( TheStreet) -- Agrium ( AGU) said it will stop pursuing its $5.4 billion acquisition of CF Industries ( CF) or the election of its nominees to CF's board. Agrium said it would allow its offer for fellow fertilizer company CF to expire on March 22. "It is unfortunate we could not conclude this transaction, given the strong support shown by both CF and Agrium shareholders," Agrium said in a press release Thursday. Agrium has been pursuing CF for about a year and its hopes for an acquisition likely were dashed by Terra Industries' ( TRA) announcement earlier this week it liked the latest bid it received from CF and plans to accept it unless it gets a higher offer from Norway's Yara International. CF has been pursuing Terra for almost a year as well and last week offered $4.7 billion in cash and stock for the company. Yara issued a press release Friday saying it wouldn't improve on its prior $4.1 billion offer to buy Terra. Terra's agreement with Yara may be terminated if Terra accepts a superior proposal. Yara would then be entitled to a break-up fee of $123 million, Yara said. -- Reported by Joseph Woelfel in New York. Follow TheStreet.com on Twitter and become a fan on Facebook.