I'm trying to figure out how best to fertilize organically in a way that suits me. My ideal is mix stuff in in spring and forget it. What I'm learning is that slow release organics like compost, manure, etc only are average 25% available in the first year. However, those same fertilizers release 90% in the first year. To reach my nitrogen goal, I have to quadruple the amount I would normally add based on the numbers I would with chemical fertilizer of the same strength. With the alfalfa pellets I'm using this year, 3-1-2, that works out ok because if you calculate the ratios based on availability, it's 0.75-0.4-1.8 if I were to add potassium in any other form, it would be too much, you see. Manure would be even more risky. Consider the other additives and the rate they are available.