A couple of times on here I've seen or been part of a discussion about manure incorporation and Nitrogen availability and it has me thinking about the possible differences in the country on this topic.  Here in PA the nutrient management regulations are pretty much written by Penn State.  Well, they don't write the regs, but, the regs reference their work and recomendations quite heavily.  So, PSU agronomy guide lists N availability under a number of different scenarios.  One of particular interest to me and been mentioned on here is N available from fall applied manure to a spring planted crop.  For fall applied manure (livestock) the available N for the spring planted crop is 20%.  That is 20% regardless of if/when the manure is incorporated.  That number drops to 15% for poultry manure.  I gather that many on here argue that these figures are too low and that less N is loss than what PSU studies say.  What are the Universities saying in your area for fall applied manure to spring crops?