Right now I'm at the Aztec section which contains the following information: learned from earlier civilizations, Aztecs farmed on floating islands, chinampa (17 long and 100-300 feet wide), able to grow 4 crops of maize a year, and interplanted with willows to keep the soil from eroding. They also irrigated, used intercropping (aka using nitrogen fixers) and terraces, and grew and ate spirulina! It's all very interesting.
I found this picture online:
Isn't that an amazing historical way to grow self-irrigated foods? Anyway, I'm learning a lot. (The focus of the lectures is mostly on cooking and history, but the ways foods have traveled, tastes have changed, and the development of agriculture all feed into it. I feel smarter already from listening to it, although I may have to listen to it twice to get everything. We'll see.)
These data clearly indicated that during radiation frost conditions, a microclimate develops that is considerably and consistently warmer then the air above a similarly positioned dry land field.
The author concludes that sub-irrigation has been overemphasized as a feature of both pre-Hispanic and modern wetland agriculture, while frost risk reduction has been an under appreciated result of the creation of chinampa agriscapes. Restoration of past water levels in the chinampa canal system may be desired primarily to achieve increased frost risk reduction, not sub-irrigation
Wikipedia says up to seven harvests per year! And this:
They were created by staking out the shallow lake bed and then fencing in the rectangle with wattle. The fenced-off area was then layered with mud, lake sediment, and decaying vegetation, eventually bringing it above the level of the lake.
There is evidence that the Nahua settlement of Culhuacan, on the south side of the Ixtapalapa peninsula that divided Lake Texcoco from Lake Xochimilco, constructed the first chinampas in C.E. 1100
So we're talking very old permaculture techniques that were probably perfected over hundreds of years. The richness of hugelkultur and soil building techniques, protection from frost, as well as irrigation and extra harvests. Wow!!
Fascinating stuff. Maybe you guys already knew about this but I feel like I'm just scratching the surface in traditional growing techniques.
Reading about chinampas was some of my first permie porn, if you'll excuse the contemporary parlance (like food porn). I was enthralled. Connections were made in my mind with stuff that Sepp Holzer says and does, but often just throws out there as an aside, stuff that Paul has often gone on in detail about with regards to hugelkultur and flow paths for cold air down hill, some Fukuoka stuff about flooding clover lays and seasonal fish stocking, things I was reading at the time about heavy-feeding water-loving trees like willows, the natural water treatment properties of reed systems, creating habitat for water fowl, the filtration and microbiotic habitat potentials of biochar and the historic practice of making Terra Preta.
All of these things were compatible pieces of, not a puzzle, but a creator's giant erector set, a huge bucket of legos that fit together in more combinations than I could readily see at a glance.
In practical terms, I think chinampas design melded with some hugelkultur could serve very well for seasonally soggy areas, to allow for spaces for things to grow that don't appreciate wet feet, and to act as filters in areas that experience seasonal flooding. I also think that wildcrafting chinampas could be carried out to increase habitat, cover, and food sources for wild waterfowl. The perimeters of these could easily be planted in wild rice and other plants that tolerate or even thrive with wet feet, and could provide food for human consumption beyond hunted waterfowl.
It doesn't matter how long you've been reading up on this stuff. Permaculture has a way of surprising you, and insight can be gained simply by interacting through posts with others on this site.
Personally, I am delighted that you're so engaged by your reading material. I love it when I get into things that way. I wish everyone could be, much more often.
Well, keep it up. No observation is insignificant, and insight can be found through fresh eyes. Keep scratching, and let us know what you dig up!
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
I've also thought about -- but not implemented -- chinampas as a way to incorporate aquaponics into permaculture. The problem with most aquaponic setups is that they require at least an electric water pump and a lot of plastic pipe. But the small change in elevation between water and land in chinampas means that a simpler bubble pump or mechanical pump could do the trick; you could even manually scoop up water a few inches into a trough.
Chinampas would work very well in an aquaponic pond, there would be no need for pumps since the water level remains fairly constant and the large pond will set up a current which will move the nutrients around the pond, making them available for the plant roots.
I think the method would work great with a three sisters type planting or any other type of multiple plantings.