Japan does plenty of the exact same things as we do in the USA agriculturally. CA grows more rice than all of Japan, I live right in the middle of it here.
ADA does add a great deal of N and P to the aquarium, it's just mostly in the sediment in a nice form that we can work with. But folks seem to assume that because their cheap test kits that only measure the water column parameters does not detect much, that it's not there.
You have to test both locations, not just one.
Kasslemann implied this same oversight in her talk at the AGA, never tested the sediment more or even gave it passing mention.
If you bother to go to the trouble to do research on aquatic plants, you'd darn well better measure the test the sediment.
But few do, then assume it is some mystery how the plants grow well
A few simple test can show how and why they grow well in several situations, all of which point to that plants are opportunistic, they take nutrients from either location readily.
But do not forget, you are adding a few months to year's worth of N and P into your tank when you add ADA sediments.
That is a large departure from the inert sediments like sand, etc.
But then they worry about KNO3 dosing...........
There is a lot of low level NH4, which is far more toxic and likely to impose health concerns , especially when uprooting etc, than KNO3..........
Regards,
Tom Barr