http://www.agrimoney.com/news/ubs-lifts-potash-price-target-as-india-deal-looms--3139.html
soory dont have a site that constantly updates the price wish i did :p but these are UBS's forecasts
2015: $550 a tonne, (+$90 a tonne)
2014: $520 a tonne, (+$60 a tonne)
2013: $520 a tonne, (+$60 a tonne)
2012: $500 a tonne, (+$40 a tonne)
2011: $465 a tonne, (+$35 a tonne)