My guess is that once your nutrients have been cycled adequately your N supply will quickly run out... as long as you have OM in decay N is being released... once your OM has decayed as much as it is going to, then only the additions will supply the N... Does Sumagreen have N, in it???
In answer to your other question:
I'm experimenting with compost applications in various soils and contexts, for exa., will try on lawns that lack color/luster during the summer months...
Now that I know that clay's texture(platelets) has nothing to do with water infiltration, percolation, or drainage,,, I wonder what does...