POT has fallen because some hedgies/funds had to sell to meet redemptions. Period. This sell off has nothing to do with some new valuation metric. I think traditional financial metrics of EPS growth, PEG, cash flow, and yield still apply and using these metrics POT is a very attractive name.
The business is straight forward, the balance sheet is transparent and strong, cash flow is very strong, the PEG is low, market demand for potash far exceeds supply and will for the foreseeable future.
The old adage buy low applies for patient investors. If you wait for the charts to look good you will be giving up 20-30% upside from current levels. I remember when the chartists recommended buying the breakout of $240!!