Native American History Month: Crop Rotation and the Three Sisters
November is Native American History Month, which is an opportunity to learn about the many ways Native peoples have contributed to the growth of the US and the struggles they still face today. The rich and diverse cultures of Native peoples and the oppression they face today are significant across the globe all year round. Here is a little tidbit about a cool scientific process that many Indigenous tribes have used to protect the land and provide food.
Since World War II, the US has increasingly grown crops in monoculture, which is growing only one type of plant in an area at one time. For example, an entire field might be used to only grow corn. Monoculture offers many advantages, especially in the short-term: increased efficiency, more opportunities for automation technology, and easier management.
However, monoculture has many disadvantages as well, both in the short- and long-term. Efficiency for growing also offers opportunities for efficiency for pests, so monocultures often need more pesticides. These crops face are more susceptible to environmental changes (Climate Change, anyone?) and disease, because there is less genetic diversity. When done year after year, monocropping can deplete soil of nutrients so it can no longer be used.
Many Indigenous tribes have long used a better system for growing certain crops, the Three Sisters. In addition to being part of the mythology of tribes such as the Hopis of the Southwest, the Oneidas of the Midwest, and the Iroquois in the Northeast, the Three Sisters describes three different plants that, when grown together, offer a model of environmental sustainability.
The Three Sisters refers to the combination of corn, climbing beans, and winter squash grown together at the same time. They live in symbiosis, which means they interact with - and often benefit from - each other. According to a PBS article that describes the agricultural and cultural significance of the Three Sisters, “They’re planted in a symbiotic triad where beans are planted at the base of the corn stalks. The stalks offer climbing bean vines support as they reach for sunlight from the earth. The beans, in turn, pump beneficial nitrogen back into the soil, fertilizing the corn and squash, while the squash's broad, spiny leaves protect the bean plants from predatory animals.” The Three Sisters can also help the soil maintain its nutrient balance, prevent erosion, and control weeds.
In addition to environmental advantages, the Three Sisters also provide all essential amino acids, as well as protein and fatty acids, we need to survive. In fact, in a direct comparison to monocropped corn, the Three Sisters provide just as much energy with more protein, per hectare.
This combination of crops can not only provide additional nutrition in the same farmed area, but can also allow the land to provide for much longer.
Sources:
https://nativeamericanheritagemonth.gov/about/
https://eos.com/blog/monoculture-farming/
https://www.pbs.org/native-america/blogs/native-voices/meet-the-three-sisters-who-sustain-native-america/
https://en.wikipedia.org/wiki/Three_Sisters_(agriculture)