i recently saw a video, i thought it was linked to from permies but i cant seem to find it right away at the moment
but here is another video in which they grow azolla with the rice -acting sorta as a ground cover:
great I'll check that out - polyculture 2 is better than just rice! it would be great to make a true polypaddy... guess that might just look like a soggy weed ditch
well that video i saw had a third that grew a little higher, maybe by an inch or two tops than the duckweed, i think it was water chestnut but im not too certain aobut that - might have been watercress
also here is plants for a future's list of plants for an edible pond/bog garden, you could try growing a few of these along with the rice, get soem more diversity going...
no problem, best of luck with everything, do post a thread of your "plots" when you get them up please, always cool to see what other permies are doing with their knowledge:)
We so far have only planted rice and azolla (not really planted but in there). We'd like to try others but have yet to ID them.
Swales could work if you could keep enough water in them to deter the weeds.
No magic ratios I know of...