Most 46-0-0 urea products are water soluable (little if any slow release -- maybe as much as 20 or 25 % slow if you buy the good stuff), but after a very short while, the bags get hard as a rock and impossible to spread through a hopper. Years ago when we used 46-0-0, my guys were slamming down these bags on the street to break them up.......then we hoped the screen in the hopper would keep the rest of the chunks out , but that was a pipe dream. Stacking pallets three high made matters even worse. On humid days, we were cleaning our impellers several times a day. Then there were the bags left over the following spring. 46-0-0 is a fine winterizer fert, but we prefer some sort of SCU (slow release) for the above reasons, plus much less dust -- especially if we have lots of precip before winter so it doesn't wear off too soon. Then there's the potash issue. Many upper Midwest universities recommend potash for late fall. BTW I remember buying urea for $4.00 per 50 pound bag off railroad cars. My two cents worth.