Dahlman Rose turns cautious on fertilizer shares, believing upside from the 2013-14 crop has largely played out and drought conditions introduce a multitude of downside risks which outweigh the rewards, especially if ethanol comes into the mix. The firm downgrades POT -2.4%, AGU -0.2% and RNF -1.6% to Hold but keeps MOS -1.2% and CF -0.2% at Buy.