Plant cultivation includes a whole range of human behaviors, from watering, to weeding, to the construction of drainage ditches, which are designed to encourage the growth and propagation of one or more species of plants. Cultivated plants are distinguished from domesticated plants, which show morphological changes, indicating that they are genetically different from their wild ancestors. In many cases, early domesticated plants are so different from their wild progenitors that their reproduction depends on human interference. For example, in wild cereal plants, the rachis, the axis of the plant to which the grains are attached, is brittle. When the cereal grains ripen, the rachis shatters, allowing the grains to disperse and the plant to reseed itself. Early domesticated cereals have a nonbrittle rachis and depend on humans for their propagation. While plant cultivation is certainly an early stage in the process of plant domestication, plant cultivation does not always lead to domestication.
Recovery of Archaeological Plant Remains
To study plant cultivation and plant domestication, archaeologists must be able to recover plant remains from archaeological sites. A technique known as flotation is generally used to recover archaeological plant remains. Flotation, or water separation, uses moving water to separate light organic materials, such as seeds and charcoal, from archaeological soils. Most flotation machines include a large tank with a spout that pours water into a fine mesh strainer. A large tub with a screened bottom fits inside the tank. The screen, which is often made of window screening, is used to catch heavier artifacts, such as stone tools and pottery shards. When a measured sample of archaeological soil is poured into the flotation machine, the light organic materials floats to the top of the tank. Moving water carries this material down the spout and into the fine mesh strainer. The resulting material is known as the light fraction and generally includes small fragments of carbonized seeds, other plant parts, and wood charcoal. The plant remains recovered through flotation are usually studied by specialists known as archaeobotanists.
Archaeological and Ethnographic Examples of Plant Cultivation
One of the best-known archaeological examples of plant cultivation comes from the site of Netiv Hagdud in the West Bank. The site originally covered about 1.5 hectares and has been dated to between 9,900 and 9,600 uncorrected radiocarbon years BP. Three seasons of excavation at Netiv Hagdud, under the direction of Ofer Bar-Yosef and Avi Gopher, produced the remains of several small oval houses with stone foundations, as well as storage pits. The stone tools and other artifacts from Netiv Hagdud indicate that it was occupied during the Prepottery Neolithic.
The excavations at Netiv Hagdud also yielded over 17,000 charred seed and fruit remains, including the remains of cereals, legumes, and wild fruits. Barley was by far the most common cereal recovered from Netiv Hagdud, making up about 90% of the remains of grasses. However, the barley remains from Netiv Hagdud were morphologically wild. Based on the large quantities of barley remains that were recovered, the excavators of the site have suggested that Netiv Hagdud’s economy was based on the systematic cultivation of wild barley. In this case, plant cultivation represents an intermediate point between the plant-gathering economies of the Late Pleistocene and true plant domestication. Morphologically domesticated barley has been recovered from many later Neolithic sites in the Near East, and domesticated barley and wheat became the dominant cereal grains throughout later Near Eastern prehistory.
Ethnographic studies of traditional Aboriginal plant use in northern Australia provide similar examples of what might be termed plant management, or even plant cultivation. When Australian Aborigines in the Cape York province region of northern Australia harvested wild yams, they often replanted the tops of the tubers in the holes. The top of the yam is the portion of the plant from which regeneration takes place. Yams were also planted on islands off the coast of Australia, to extend the range of these plants and to serve as stores for visitors who might be trapped on these islands. These essentially horticultural behaviors were observed among people classified by anthropologists as hunter-gatherers.
Australian Aborigines also used fire to increase the productivity of cycads, whose seeds were collected for food. Many of the dense stands of cycads seen in northern Australia today may be a result of Aboriginal burning. The use of fire to control the distribution of plants (and animals) is well documented in the ethnographic and archaeological record of Australia. Other prehistoric hunter gatherer populations who used fire to control the distribution of plants and game include the Mesolithic foragers of northern Europe and the Archaic hunter-gatherers of eastern North America.
From Foraging to Farming
The transition from hunting and gathering to agriculture is one of the most important changes in all of human prehistory. Archaeological evidence from sites such as Netiv Hagdud suggests that plant cultivation may have represented an important stage in the transition from foraging to farming. However, hunter-gatherers sometimes practiced behaviors that may be interpreted as plant cultivation, since they were designed to encourage the growth of favored plants. These data suggest that plant cultivation may not always have led to plant domestication.
References:
- Bar-Yosef, O., & Gopher, A. (Eds.). (1997). An early Neolithic Village in the Jordan Valley, Part I: The archaeology of Netiv Hagdud. Cambridge, MA: Peabody Museum of Archaeology and Ethnography, Harvard University and American School of Prehistoric Research.
- Cowan, C. W., & Watson, P. J. (1992). The origins of agriculture: An international perspective. Washington, DC: Smithsonian.
- Lourandos, H. (1997). Continent of hunter-gatherers: New perspectives in Australian prehistory. Cambridge: Cambridge University Press.
- Sobolik, K. D. (2003). Archaeobiology: Archaeologist’s toolkit. New York: Alta Mira.
