Jana Partners LLC plans to propose a slate of five nominees for fertilizer maker Agrium's board, saying the company needs better oversight to help manage costs and boost its stock price.

Jana, an investment advisory firm, is Agrium Inc.'s biggest shareholder. The company said Monday that its board nominees include David Bullock, Stephen Clark, Mitchell Jacobson, and Lyle Vanclief. It also includes Jana managing partner Barry Rosenstein.

Bullock is the former chief financial officer of plastic packaging supplier Graham Packaging Inc. Clark is the former CEO of Brenntag AG. Jacobson is chairman of MSC Industrial Direct Co. and Vanclief is the former Minister of Agriculture and Agri-Food Canada and was a Parliament member.

Agrium's stock dropped sharply earlier this month after the Canadian company's forecast for its current quarter came in well short of analyst projections. Agrium warned that there are signs of weakening demand for phosphate, a key ingredient in one type of fertilizer, while uncertainty regarding supply agreements with China and India over potash fertilizer is affecting that market.

The company sells three major types of fertilizer — nitrogen, phosphate and potash — in North and South America as well as Australia.

Jana has been pushing for changes at Agrium, including spinning off its retail operations into a separate company. Aside from looking to control costs better and raising its stock price, Jana also wants Agrium to improve its capital allocation.

Agrium's U.S. shares closed at $97.58 on Friday. They traded as high as $108.42 on Oct. 24 and as low as $63.39 in mid-December 2011 over the past 52 weeks.