By Leia Michele Toovey-Exclusive to Potash Investing NewsThe potash market is waiting with baited breath for Thursday, when Potash Corporation of Saskatchewan (NYSE: POT) will release its Q4 earnings, as well as its targets for the 2011 season. As the largest potash producer in the world, Potash Corp.'s 2011 market projections will provide key insights into how the market will behave over the coming months. Expectations for fertilizer demand in 2011 are already sky-high, with farmers eager to lock in fertilizer purchases in the midst of rising grain prices. This optimism is already “baked-in” to Potash stock, so in order for the company to post further gains, potash prices and volumes will have to edge up. "In our opinion, the price of the stock is going to pretty much hit a wall between $160 and $170 ... until we see a spike in potash prices well above the $400 (a tonne) range," commented one analyst. While prices have jumped in North America to more than $550 a tonne, pricing gains on key overseas contracts have not kept pace. A recent deal with Chinese buyers settled at $400 a tonne. Before Potash shares can make another substantial leap, analysts claim that overseas contracts will have to match those being settled in North America. In October, Potash Corp forecast 2011 earnings of $8 to $8.75 a share. Investors now have their sights set higher as analysts are already calling for earnings of at least $8.89 a share. Potash Corp, which sells more of its namesake crop nutrient than any other producer, has already forecast 2011 sales of 9.3 million tonnes. After touching a 28-month high of $174.31 recently, the shares could now stall, with the stock already trading at more than 18 times forward earnings-per-share expectations.