Glad to see this being discussed. Since first reading up on the permacultural uses of hemp, I have always wanted to work it into the mix in a pasture setting. I would love to see if browsers like goats would find it appealing, because it grows like, well, a weed. Add to that the benefits of seed in the diet of the livestock that browse/graze the land, and I could see myself working to naturalize it there.
I think the only place that you could squeeze the maximum value out of the plant would be in a pasture setting. I know the idea of function stacking is appealing, but honestly, the methods and varieties for the different functions are quite different. If you are producing hemp for the bast fibre, for instance, plant spacing is much closer to reduce branching (less branching equals better quality and quantity of bast fibres). If you are producing cannabis for its pharmaceutical properties, not only are there vast numbers of strains for specific
medicinal and recreational properties, the flower buds must be harvested without pollination to achieve best potency, which obviates the possibility of getting seed from the same plants. Which ignores the fact that there are strains of hemp that have been bred specifically for their desireable oilseed-producing traits as different from smoking cannabis as a cultivated plant is from a wild one.
It's like sheep. I would love multi-purpose sheep. Or goats. But the fact of the matter is, a dairy breed will likely outperform any multi-purpose breed in dairy. A fibre breed will do the same in fibre. The more functions you try to extract from the same stage or life cycle of any individual, the smaller the quantities or qualities of those stacked functions will yield (with exceptions; stacked functions that reinforce each other are obviously another matter).
So while you might get a yield of seed from your fibre crop, it might not be good seed except to plant your next fibre crop, nor might it be good for the fibre you seek to produce to leave it growing that long (I don't know, my focus hasn't been on hemp bast production). If you let your medicinal cannabis get seedy, you will lose potency. If you space your oilseed hemp closer to yield more bast, you will get less branching and a decreased seed yield because of it, and the bast you harvest won't compete with the stuff grown primarily for fibre.
Does this mean I won't have a dual-purpose breed? Of course not. I would love a dairy/fibre breed that clears brush and leaves me a decent carcass at the end. But I will be resigned to the fact that I will only get two of these, realistically, and I won't likely get as much
milk, or fibre, or meat as I would like. But I will get brush cleared, and nutrients cycled through their manure. A real triple-purpose would be quite the feat of animal husbandry, if it is even possible.
So be aware that, as with many other function stacking situations, trying to squeeze everything out of every situation might sound great, but you may be doing your efforts a disservice by trying to stack competing functions.
Let them specialize. Have oilseed hemp. Have fibre hemp. Have medicinal cannabis. Use the closely-spaced fibre hemp as a windbreak. Use the oilseed hemp canopy to shade out persistent unwanted volunteers, or experiment in companion planting as shade structures for shade-loving crops. Enjoy the medicinal cannabis. Don't stress about stacking every little function just because you
should be able to, theoretically, at least in principle, you think.
And for God's sake, keep the seeds separate. (hahaha)
-CK
A human being should be able to change a diaper, plan an invasion, butcher a hog, conn a ship, design a building, write a sonnet, balance accounts, build a wall, set a bone, comfort the dying, take orders, give orders, cooperate, act alone, solve equations, analyze a new problem, pitch manure, program a computer, cook a tasty meal, fight efficiently, die gallantly. Specialization is for insects.
-Robert A. Heinlein