The products I look at have pretty low N and not enough to elicite the responce seen. Even if the product were 100% N and Fe the application at 8# per AC would not give the responce alone. As a matter of fact there is little we can do to significantly change the soil hence the reason we have to keep applying fertilizers of any type to turf. Granted, a little bit of sugar and colonizing with microbes there is little chance they will thrive in poor soils. The Carbon / Nitrogen cycles and the impact on plants and bacteria is pretty complex and never in a steady enviroment. In an old forest we have leaves fall, and continually decomposing over centuries.... in turf we rake up the leaves and often take away the grass clippings.