This is common in fertility experiments. In field studies using 15 N we can find 15 N in the uprights by 24 hours after application. Mineralization, the process through which organic N is released as ammonium, is microbe mediated and therefore the process is temperature dependent. Further the soils must not be wet , just moist. There is no formula to determine mineralization.
Cranberries are relatively shallow rooted.
In my opinion little to no N would be available to cranberries under a 6-8 sand lift. Foliar N applications have their place. They are most effective when uprights are growing poorly or look pale. Foliar applications are expensive, but will green vines up in a short time. However, cranberry uprights cannot absorb sufficient N through the leaves to meet their full N requirement.