[culi]

Yup. A lake that used to fuel the single most productive agricultural system humans have ever practiced. It's sad but there is a strong indigenous movement to bring them back. The axolotl actually became a major symbol of indigenous resistance because of this movement

[trhway]

How it was (a great interactive 3d reconstruction)

https://tenochtitlan.thomaskole.nl/

[culi]

This is awesome, thanks for sharing.

Andrew Wilson, who works with the United Nations World Food Program, also made an in-depth minidoc on them: https://www.youtube.com/watch?v=86gyW0vUmVs

[palata]

Wow this is amazing. Thank you!

[trhway]

Thanks to the author and HN - it was posted here sometime ago, and being that impressive it naturally stuck in my memory like i'm sure now it will in yours :)

[ch4s3]

> the single most productive agricultural system humans have ever practiced

This is simply not true. The highiest maize yield per hectare I can find anywhere online for chinampas is less than half the 13.5 metric tons per hectare that farmers get in Iowa. The more reputable numbers are less than 1/4 of that. It's probably true that they were among the most productive pre-modern agricultural plots which is a great achievement, but there's no need to make things up.

[culi]

I'm not being hyperbolic.

They produce a lot more than just corn. Not only can they be farmed for hundreds of years without break, but they can be harvested 4 to 7 times per year. They are 13 times as productive per unit of area as conventional dry-land farming.

> In Xochimilco, roughly 750 hectares of active chinampas produce around 80 tons of vegetables daily. This translates to a massive, continuous, year-round output of over 38,000 tons per year across the entire area

So that translates to 50.7 metric tons per hectre.

---

> the most productive pre-modern agricultural plots which is a great achievement, but there's no need to make things up

Post-industrial agriculture is not actually more productive per area. It's just more productive per input labor.

> Agricultural yields within the most densely populated and productive preindustrial land-use systems compared well with modern yields and were sustained in some regions for centuries to millennia, even though they also tended to require extreme inputs of labor and other socially unsustainable hardships

https://www.pnas.org/doi/10.1073/pnas.1217241110

[ch4s3]

That article you linked doesn't mention Xochimilco at all so I have no clue what you're quoting. I can't find a single source for your 80 tons claim (other than some blog post that cites another blog post), which if true and I suspect it isn't is 20 tons less per hectare than many conventional vegetables like cabbage and tomatoes. Other sources I found cite a number that's less than half of what you're claiming. Do you have a real source that isn't a blog post?

>Post-industrial agriculture is not actually more productive per area. It's just more productive per input labor.

This is alarmingly false. As I pointed out many conventional vegetables yield 100 tons per hectare today. Moreover yes they are more productive per unit of labor. The Mexica and their contemporary polities around Lake Texcoco were miserable slave societies that used armies of captured war salves (tlacotin) to perform much of the work. They also used unpaid corvee labor through the coatequitl system, and serfs known as mayeques. So honestly its quite the social advancement that we don't have to press people into agricultural labor at spear point anymore.

> Agricultural yields within the most densely populated and productive preindustrial land-use systems compared well with modern yields

The references for this quote are about South East Asian rice agriculture, which today is still done more or less done the way it was in premodern times. This quote doesn't support your argument and is at best deceptive.

[culi]

I was addressing two separate points you made. I thought the "---" would make that clear.

> This is alarmingly false.

I'm sorry but I can't take your comment more seriously than a paper published in a respected journal that has been cited 1,099 times. It provides 4 sources to back up the claim I posted.

In scholarship on land use history this is pretty well accepted.

---

As for the specific chinampas yields, such high yields shouldn't be surprising when you have 4-7 harvest per year and require no periods of being fallow.

The UN's FAO provides more specific breakdowns on yields on page 22 of their report

https://openknowledge.fao.org/server/api/core/bitstreams/cd8...

You're have to download it but the designation also has more specific figures

https://openknowledge.fao.org/items/ba8d198e-a18b-4541-b94b-...

[ch4s3]

Your source says:

> It is clear that the yield per crop varies depending on the species and variety sown. However, in the case of the chinampas, yields are between 10 to 15 tonnes/hectare. An average of 12.5 tons/ha

That's not 80 tons per hectare as you stated.

> I'm sorry but I can't take your comment more seriously than a paper published in a respected journal that has been cited 1,099 times

You took the quote out of context, it's about rice agriculture in South East Asia, not Xochimilco. I check the citations and you obviously didn’t.

You are blatantly making things up here and trying to back your bullshit claims with papers that you are misrepresenting.

[zeckalpha]

How much fertilizer does the Iowan farmer need to add to their field to achieve that? How many years can they maintain that yield without eroding the soil?

[UncleOxidant]

How many years can they maintain that without petroleum inputs?

[ch4s3]

Ammonia can be generated through electrolysis as feed-stock for Haber-Bosch to get nitrogen, so literally forever. The reason we use petroleum is because it's currently cheaper than solar PV electrolysis.

[UncleOxidant]

Sure, but it would take some time to transition to ramp up production to the scale required by world-scale agriculture. We're using petroleum for this because it was cheap & easy. Not saying we can't transition, but it will take time.

[ch4s3]

Right, but it's possible with existing tech and there's no scenario where oil disappears all at once. Its a highly geographically distributed resource.

[ch4s3]

Who cares? Fertilizer is nitrogen that literally comes out of the air. Erosion is vastly overstated by permaculture enthusiasts and can be mitigated vy changes to tillage and irrigation. Erosion in the Midwest clocks in at about 0.04 mm per year, but there's plenty of new soil deposition around the Mississippi. It's a manageable issue.

[greenie_beans]

this is extremely wrong, but anyway back to my day because there is just too much wrong in this to respond to each wrong phrase

[ch4s3]

Extremely wrong how? There's a great an well sourced section in Vaclav Smil's How to Feed the World about this very topic. I also cited a specific erosion figure. But I guess that doesn't matter.

[greenie_beans]

looking forward to reading it! definitely skeptical about your erosion rates, will have to go do my own research later (quick look, USDA estimates for the Corn Belt (~5 tons/acre/year on average)). if your info is coming from one book then i'm doubly skeptical, though i would bet that a soil scientist would probably agree with me and i'm def wondering if you might've misread the book?

i'm not a farmer, but i do manage woodlands, have a huge garden, volunteered on farms over the years, worked in a sustainable ag non-profit, and have even tried distributing sweet potatoes, etc, so i have an avid interest in agriculture and our food system.

aside from the fact that the soil is one of the three most important components for growing food, therefore it's extremely important to take care of it if we want our species to live into future centuries... there is a lot of evidence that shows that industrial ag creates erosion problems (one easy example: all of the national forests in my area was degraded farm land that they converted to woodlands in the 30s, because they learned this fact that hard way then). believing that hunger is a solved problem because of 20th century style agriculture is a fallacy. the dust bowl is one historical example that shows how this system can fail spectacularly, and it's all based in how we manage the topsoil, a natural resource just like oil or water.

we lost the moment we tried to overcome natural systems with chemicals (we've had a good run but i believe it's gonna be an anomaly in history). you can use science + natural systems in your favor to grow food. taking care of the topsoil is objective number one. food is a byproduct of good soil. the soil is a living system and chemicals kill that ecosystem to our detriment.

technology is definitely not the answer here. you are welcome to go try to grow food on mars without soil. good luck!

[zeckalpha]

Just like the sun streams lots of power to us!