Eastern Agricultural Complex

The Eastern Agricultural Complex in the woodlands of eastern North America was one of about 10 independent centers of plant domestication in the pre-historic world. Incipient agriculture dates back to about 5300 BCE. By about 1800 BCE the Native Americans of the woodlands were cultivating several species of food plants, thus beginning a transition from a hunter-gatherer economy to agriculture. After 200 BCE when maize (Zea mays, commonly called "corn") from Mexico was introduced to the Eastern Woodlands, the Native Americans of the eastern United States and adjacent Canada slowly changed from growing locally cultivated plant species to a maize-based agricultural economy. The cultivation of local indigenous plants other than squash and sunflower declined and was eventually abandoned. The formerly domesticated plants returned to their wild forms.

The first four plants known to have been domesticated at the Riverton Site in Illinois in 1800 BCE were goosefoot (Chenopodium berlandieri), sunflower (Helianthus annuus var. macrocarpus), marsh elder (Iva annua var. macrocarpa), and squash (Cucurbita pepo ssp. ovifera). Several other species of plants were later domesticated.

The term Eastern Agricultural Complex (EAC) was popularized by anthropologist Ralph Linton in the 1940s. Linton suggested that the Eastern Woodland tribes integrated maize cultivation from Mayans and Aztecs in Mexico into their own pre-existing agricultural subsistence practices. Ethnobotanists Volney H. Jones and Melvin R. Gilmore built upon Ralph Linton's understanding of Eastern Woodland agriculture with their work in cave and bluff dwellings in Kentucky and the Ozark Mountains in Arkansas. George Quimby also popularized the term "Eastern complex" in the 1940s. Authors Guy Gibbons and Kenneth Ames suggested that "indigenous seed crops" is a more appropriate term than "complex".

Until the 1970s and 1980s most archaeologists believed that agriculture by Eastern Woodland peoples had been imported from what is now Mexico, along with the trio of subtropical crops: maize (corn), beans, and squash. What became accepted by the 21st century is that agriculture in the Eastern Woodlands preceded the import of crops from Mexico and that the Eastern Woodlands were one of about ten cultural regions in the world to become an "independent center of agricultural origin." In the 1970s and 1980s, new archaeological techniques demonstrated that by 1800 BCE the Native Americans of the eastern woodlands had learned to cultivate indigenous crops independently and that indigenous crops formed an important part of their diets. A major element in determining that plants were cultivated rather than being collected in the wild was the larger size of edible seeds and the thinner seed coat of the domesticated plant compared to its wild relative, an attribute of domesticated crops that came about through human selection and manipulation. When cultivation of most indigenous plants ceased in favor of maize agriculture about 900 CE, seed sizes and seed coats of plants reverted to their former uncultivated size and thickness.

The earliest cultivated plant in North America is the bottle gourd, remains of which have been excavated at Little Salt Spring, Florida dating to 8000 BCE. Squash (Cucurbita pepo var. ozarkana) is considered to be one of the first domesticated plants in the Eastern Woodlands, having been found in the region about 5000 BCE, though possibly not domesticated in the region until about 1000 BCE. The squash that was originally part of the complex was raised for edible seeds and to produce small containers (gourds), not for the thick flesh that is associated with modern varieties of squash. Cucurbita argyrosperma has been found in the region dated to circa 1300-1500 BCE. C. pepo cultivars crookneck, acorn, and scallop squash appeared later.

Other plants of the EAC include

The plants are often divided into "oily" or "starchy" categories. Sunflower and sumpweed have edible seeds rich in oil. The seeds of erect knotweed and goosefoot are starches, as are maygrass and little barley, both of which are grasses that yield grains that may be ground to make flour.

The archaeological record suggests that humans were collecting these plants from the wild by 6000 BCE. In the 1970s, archaeologists noticed differences between seeds found in the remains of pre-Columbus era Native American hearths and houses and those growing in the wild. In a domestic setting, the seeds of some plants were much larger than in the wild, and the seeds were easier to extract from the shells or husks. This was evidence that Indigenous gardeners were selectively breeding the plants to make them more productive and accessible.