Closed System Edible Landscape

Maybe a little over a decade with hugelculture. Colder climates have a long period of time each year were soil biology all but stops for the winters and slower periods leading into and leaving that hibernation. Warm climates keep chewing away at a steady pace year after year without stop.

I'm certain you can grow nitrogen fixing crops and still get a harvest. Theoretically you're supposed to cut the legumes down when the start to flower but before they set seed, but there is a obvious difference between the patch of lawn where I let the bluebonnets set seed and the rest that didn't have bluebonnets grow there. What I suspect is actually true is that you will not fix as much nitrogen if you let your legumes go to seed (form beans, peas, ect).

Generally when they speak of planting support species in a food forest I think they're speaking of nitrogen fixing trees. I could see those being able to fix a lot more nitrogen a lot faster than a herbaceous annual.  I still have apparently healthy roots from last year's runner beans, so I may be able to recommend at least one highly productive perennial nitrogen fixer. They didn't survive until I planted them in the shade, so they're also a great candidate for a food forest.

So, what would be some plant-once-and-forget, high-yield food crops that would grow in my area (zone 9)?
Stuff that "grows like weeds" and is dense in nutrients, calories, or both?

If you've grown any of the crops listed here so far (including http://www.thesurvivalgardener.com/rabbit-trails/survival-plant-profiles/ and http://perennialvegetables.org/perennial-vegetables-for-each-climate-type/hot-and-humid/ ) please tell me about your experience with them.

BioIntensive also list filbert(nuts in general) and raisin(fruits in general). So it doesn't have to be all annual.

The main reason why you need carbon farming is to create humus that maintain soil structure thus no till and also hold water+mineral. But that can be achieved with bio-char. And so no need for the carbon-farming and worry about manure composting/reducing the amount of carbon in the soil.

So I would double dig then add biochar, mineral, worm tea, mushroom slurry and compost.
I would then follow the bio-intensive rule of 4000sqft/person + 25% more for walkway (swales+dutch clover).
60% of Land Nut/Fruit/Berry/Grains (Zone 3 - 2400sqft)
30% Calorie Roots (Zone 2 - 1200sqft)
10% Vegetables (Zone 1 - 400sqft)
House (Zone 0)

60% = 2400sqft this will fit ten 15ftX15ft trees (nut/fruit trees) 10 hazelnut trees actually provide all calories/adult for a year.
30% = 1200sqft Potatoes/Jerusalem Artichokes/Sweet Potatoes/Parsnip each require about this much space for all cal/year.
10% = Like you BioIntensive Numbers come from a zone 9b/10a area (Palo Alto, CA). So you are good with vegetables+herb

Vegetables
Cabbage/Kale Family
Spinach/Swiss Chard Family
Lettuce/Sunflower Family
Herbs
Carrot/Celery Family
Thyme/Mint Family
Garlic/Onion Family

I also see some numbers where he said that 7,500sqft will feed a non-grazing cow (harvest and bring it the cow).
He warms that the cow will get all the carbon/stalk that was suppose to be composted so we will have to import compost for 2/3 of the 7,500sqft. But with our bio-char we don't have to worry about carbon, and I don't mind importing some rockdust/sea90/lime for mineral. Because He already states I am going to have to import some if I don't compost my human poop and add it back to my 4000sqft.

Would the carbon in the biochar replace all the carbon needs of the soil? Or just the structural part? Would the soil still need decomposable carbon to keep microorganisms happy?

Well they farm carbon every year to create compost rich in.
1) Soil life
2) Mineral
3) "Water+Air Pocket"
4) "Soil Life Food"
5) "Soil Life Space/House"

BioChar will provide
1) Soil Life - We might have to air worm tea/compost tea, etc
2) Mineral - BioChar/Activated Carbon will stop the minerals from leaching away
3) Water+Air Pocket - Even better than Compost
4) Soil Life Food - The plant roots will trade with the soil life
5) Soil Life Space/House - BioChar is better than compost.

It is not a matter of BioChar equals no compost/woodchip/etc.
We will still do some just alot less, and we will multiply it with worm tea
I will have to add soil life mineral because I will not be returning human manure.
Worm Tea will add the plant food via sugar to multiple them. Afterwards the plant will trade sugars with the soil life.

Also the perennials don't really want "compost/bacterial" soil life. They prefer fungal soil life, which require roots extrude and lignin (wood/fall leaves) vs cellulose/starch/simple sugar(grass/vegetables)

Yousif Quadir wrote:
Stuff that "grows like weeds"

Weeds.

No, seriously. The reason so many invasive plants originated from horticulture is because gardeners like their plants invasive. "Fast growing, low maintenance" is the very definition of invasive. As long as this is what gardeners want, invasive plants will continue to proliferate.

Yousif Quadir wrote:Can the 90% support species be edible?

Many of the "support" species ARE edible. The trick isn't to just plant anything that fills the need, but to identify the multitude of plants that fill the need and decide which will work best in your situation. You already mentioned insectaries and nitrogen fixers. Those are both support plants. So at this point, if you're already growing those, determine how much more you would need to supply your required amount of those things.

I'm in a very different situation than you (dry, rocky, nutrient depleted soil, zone 5b/6a) but I'm planting things with deep roots to add to the soil. I don't pull them, just cut them off in the fall and let the roots decompose under the surface as they would in a natural system. I'm using sweet potatoes for part of this (Dad won't eat it, but it's an excellent mulch and ground cover) as well as amaranth and other "pretty" edibles.

Yousif Quadir wrote:Even if I find a nice place without an HOA, I'd like to avoid lowering my neighbor's property values by growing corn in the front yard   Amaranth is pretty, though!

The majority of my yard is visible from the street so I'm planning the visible gardens to look landscaped. Standard potatoes are actually very ornamental, and alliums, sorghum or grains can be the "grass" in a landscaped flower bed.

Of course any "landscaped" area is going to be more labor intensive, but it doesn't have to be if planned correctly. You have your groundcovers (cranberries, sweet potatoes), climbers for arbors or trellises (ornamental beans, kiwi, grapes, etc), grasses (grains, sorghum, alliums, etc), bushes (elderberry, blueberries, potatoes, etc) and overstory trees. Stick in a patch of "true" grass and border the landscape areas, few people would question it if it's well designed. If you want it to look good it is NOT biointensive, but an entirely edible landscape is definitely possible in those ppublic areas so you don't affect property values. If you have to take your choices to an HOA for approval, use latin names and provide pictures so they can see how the plant will be used. You may end up getting potatoes added to the allowed landscaping plants!