Anyone who has paid much attention to Bill Mollison or Geoff Lawton, which hopefully is most of us reading Permaculture News, has at least heard of chinampas. Chinampas were an ancient system used by the Aztecs, and it combined agriculture and aquaculture to create highly efficient, credibly sustainable, and extraordinarily productive landscapes.
The crux of the chinampa system is to build small islands and/or peninsulas that are separated by canals. The land crops, then, don’t need irrigation because the canals keep the soil hydrated, as well as fertilised. The canal bottoms can periodically be dredged for rich soil to replenish fertility in the land-based gardens, and cultivated aquatic plants, in addition to cleaning the water, can be used for nutrient-rich mulch. The canals separating the strips of land are stocked with fish and shellfish supplying much more animal protein per square meter than land-based animal systems. Productive vines can be grown on trellises over the canals to further the potential. With guidance from humans, chinampas can support themselves while supplying all of our nutritional needs.
For a further explanation of chinampas, including history and further benefits, I recommend (and can’t do so highly enough) reading Chinampas 2.0—an Elegant Technology From the Past to Save the Future, the existing Permaculture News article written by Rodgrigo Laado, an expert from Mexico. However, what I want to write about in this piece is slightly different. Watching a Geoff Lawton video (from his upcoming Earthworks course) recently, I was struck by his explanation of how to reasonably incorporate chinampa systems into small-scale permaculture designs.
I’ve been impressed by these systems for years, but I’ve often gotten hung up on how extensive they were in Mexico City. In that grandiose way, they always seemed out of reach. I don’t feel that way anymore, and that’s exciting enough to me for a little knowledge sharing. For those who have wondered how they might incorporate chinampas into their own permaculture designs, here’s the lowdown on some of what I’ve learned.
The Continuous Water Flow
In the case of continuous water flow from uphill (Is there any other kind?), chinampas can be created by constructing simply walled earthen mounds separated by canals, a la a series of close-knit swales and berms, as the chinampa maze. In this case, though, the water flow moves in, filling the chinampa canal to a set water level before being passively fed to the next canal and the next and ultimately back into the natural flow of water. In essence, this keeps the canals full, the land hydrated, and the system productive. Aquatic plants and animals can be raised in the canals, and land crops can be cultivated on the mounds. It’s a chinampa system keyed in and built atop the ground.
The Perpetual Bog
Closer to what was actually happening in Mexico, this system relies on a swampy section of landscape or a shallow lake. In this case, the canals are dug to make actual bodies of water, and the excavated earth is piled up to make actual land. Once this system is in place, as with chinampas, the excavated canal can become an aquaponic system, and the land is more versatile agriculturally. So, when a landscape has a low spot that is perpetually wet, or a shallow body of water that’s continuously drying out, there is the potential for a chinampa.
The Dam Installation
In permaculture, we are always looking for the right earthworks to hydrate the landscape, harvest rain, and extend water on a site. Consequently, dams are a common feature in designs. With dams, specifically on shallow sloping land, we have the potential to also install chinampas. The back, upslope side of the dam can be fitted with chinampa canals that backfill from the dam, and between this bit of extra excavation, there is workable land that can be used to grow trees and terrestrial crops. There is even the potential to use these canal additions as more controlled spaces for fish breeding and farming. This would be fairly minimal in terms of extra work for an earthmover building a dam.
The Downslope Swales
Geoff notes that, with the way swales consistently infiltrate water into the ground, after several years, the swelling subterranean plume will often keep swales near the bottom of a slope continually full. When this is the case, we have the potential for installing a chinampa system. Rather than leaving several meters of land between our downslope swales, we can install a series of canals and raised planting platforms. The lower swales have then been converted into a productive chinampa system, and in addition to the trees the swale has fostered, an entirely new type of ecosystem can be established and encouraged in this superbly hydrated landscape.
Hombres de Maíze (Men of Maize)
In case readers haven’t followed the above link to “Chinampas 2.0”, Hombres de Maíz developed modern day chinampa systems in the form of small, 5000-litre ponds with raised earthen beds (walled with rocks) in the centre of them, aquatic plants cultivated in sunken pots and on the water’s surface, and fish in the water. These “water beds” are self-contained ecosystems that create fertility (fish and bird manure), are self-irrigating (capillary watering similar to wicking beds), and clean themselves (carefully orchestrated nutrient cycling). These shallow pond systems could be put in series, run on a solar pump to keep the water flowing, or one could be created for a single experimental project.
While it would be a wonderful thing to have huge, citywide chinampas like in Mexico City, for me, it is beyond exciting to fully realise that we can utilise this ancient technique on our own homesteads or in our own eco-villages. For the last couple of weeks, my brain has been working overtime on a spot along the backside of our dam, one that is seemingly aching for a chinampa system to be installed. I’d read and heard so much about “the most efficient growing system ever devised by humans”, but I’d struggled to see where to implement it. Now, I’m having trouble imaging not doing so.