128 Agroecology and Sustainability
The origins of agriculture
Much is known about the where, when, and, to some extent, how, of the origins
of agriculture, but there is still considerable controversy over the why (Reed, 1969;
Higgs and Jarman, 1972; Bender, 1975; Clark, 1976; Cohen, 1977; Orme, 1977).
It is generally accepted that agriculture, by which I mean the cultivation or hus-
bandry of domesticated plants and animals, began independently in at least six
widely dispersed regions of the world – the Fertile Crescent (c. 9500 BP), Mesoa-
merica (c. 7000 BP), South America (c. 6000 BP), South-West China (c. 7000 BP)
and South-East Asia (c. 6000 BP) and Northern India (c. 8500 BP). The difficult
question to answer is why such a revolutionary event should have occurred in such
widely dispersed places, at roughly the same time.
A number of cultural explanations have been proffered (Braidwood and Howe,
1960; Braidwood and Willey, 1962; Ucko and Dimbleby, 1969) as have hypoth-
eses which suggest agriculture was a response to the pressures of an adverse period
of climate (Childe, 1936) or of population growth (Cohen, 1977). In each case the
writers have assumed, explicitly or implicitly, that the crucial advantage of agricul-
ture over hunting and gathering was its greater productivity. However, a number
of arguments suggest that, at least initially, it may have been the relative stability of
agriculture that was more important.
Hunter-gathering can be highly productive: the Pacific Coast Indians of North
America, for example, were able to support themselves at much higher densities
than agricultural groups elsewhere in the continent (Kroeber, 1939; Baumhoff,
1963). But the basic hunter-gatherer foods – migratory salmon, acorns, wild cere-
als – usually show dramatic year-to-year fluctuations, Moreover, many of the cen-
tres of origin exhibit highly seasonal and variable climates and are characterized by
mosaics of ‘good’ and ‘bad’ food-producing environments. Significantly, the
archaeological evidence reveals that, at least in the Fertile Crescent and Mesoa-
merica, agriculture remained a minor contribution to food supply for long after its
inception, 4000 years in the case of Mesoamerica (Flannery, 1969; Bray, 1977). As
Boserup (1965) suggests, agriculture may have begun by small daughter bands
migrating, in response to local population pressure, into areas more marginal for
the wild staple crops. Here the yields were likely to have been even less stable and
cultivation and domestication may have arisen as a response to this pronounced
instability.
Once, however, agriculture began to spread into other regions of the world,
particularly to temperate climates, its superiority in productivity terms was clearly
apparent and it was rapidly adopted (Clark, 1965; Ammerman and Cavalli-Sforza,
1971). There were consequences, though, for sustainability and equitability. Early
irrigation bought stresses from rising water tables and salinity; grain yields in
Sumer dropped from 1850kg/ha to 650kg/ha between 2400 BC and 1700 BC
(Jacobsen and Adams, 1958) and there is archaeological evidence of erosion turn-
ing arable to wasteland (Dennell and Webley, 1975). Equitability, too, may have
declined wherever agriculture became associated with family ownership of land.