If you jumped in a time machine and materialised 4000 years ago in what is now modern Mexico, it is likely that you would see maize being cultivated in a field called a milpa. This would not have resembled the vast fields of monocultural grain which can currently be seen in the American Midwest. The ancient maize would be mixed in with avocado, squashes, chili, amaranth, and climbing beans which would be using the maize stalks as a trellis to get closer to the sunlight. This is a highly productive arrangement, capable of producing hundreds of tons of food per hectare.
The most impressive thing about this scene is that if you returned to your own time it is possible that you might see the same milpabeing cultivated in the same way, four thousand years later. This is an extraordinary achievement in our modern agricultural world where we maintain soil fertility by either the addition of fertiliser or by practicing crop rotation. Forty centuries of continuous cultivation is probably unique in the history of world agriculture.
Even better, throw in a couple of other crops and you have yourself a complete food source. Maize provides starch but an incomplete set of proteins. Beans provide fibre and the remaining proteins that the human body needs. Avocadoes provide fat. Squashes provide vitamins and trace nutrients. Chillies provide flavour. This near-perfect combination of nutrition and agricultural stability mean that the milpa may be the most perfect agricultural system yet devised. The only input is human labour.
I’m an experimentally-minded person so I thought I’d try to plant a milpa in my family’s garden allotment in Collingwood. We selected sweet corn as our maize of choice and allowed them to grow to about a foot tall. Then we planted purple climbing beans about three weeks ago and they have started to wend their way up the maize stalks. Underneath it all we’ve planted cucumbers as our squash, mainly because my daughters love them.
As you can see, it’s working really well. I was worried that the maize would shade the others out, but it turned out that that was an excellent idea for a Melbourne summer. The cucumbers aren’t drying out too much, the maize (planted in a block for pollination reasons) is thriving, and the beans, boring though they are, don’t need to be staked to be productive.
So much of the modern agricultural system is built around minimising human labour (because it’s expensive) and making up for that with extensive chemical and mechanised input. That has been both highly productive but also highly damaging. We may be coming up to a time where growing food at home is again a good use of time and resources (as well as deeply satisfying). If that is the case, we could learn some lessons from ancient agricultural systems, in particularly the extraordinary milpa.