Environmental Engineering Reference
In-Depth Information
crops (15.3 million km
2
)—and Europe is now the only continent where less than
50% of all land used for food production is in pastures (the rate is just short of
40%): in North America the share is just over 50%, in Asia over 60%, in Africa
over 80%, and in Australia close to 90% (Rodriguez 2008). But even if we dei ne
traditional pastoral societies as those deriving at least 50% of their livelihood from
grazing animals, their numbers have been declining for many generations. Sandford
(1983) put the total number of true pastoralists at fewer than 23 million people
during the 1970s (with some three-quarters in Africa and the rest in the Middle
East and South and Central Asia), and since that time the numbers have declined
substantially.
The three countries with the largest pastoralist populations, Sudan, Somalia, and
Ethiopia, have suffered from years of war, while the pastoralists in both the eastern
and western parts of the continent have seen their pastures degraded by drought
and overgrazing and reduced by the expansion of cropping and nature reserves.
Pastoralism now accounts for signii cant shares of agricultural output only in the
poorest arid countries of Africa (Sudan, Mauritania, Niger, Ethiopia), and even there
it now contributes less than 10% of the total GDP. That share is less than 2% in
the Andean countries (alpacas) and a small fraction of 1% in Australia and Spain
(cattle and sheep).
Traditional Agricultures
Net energy returns in early farming were no or only marginally higher than in for-
aging, and peasant diets became even more plant-based than was the case with many
foragers, but only permanent cropping could support higher population densities,
by combining the cultivation of a large variety of annual and perennial plants with
the breeding of several species of domesticated mammals and birds and, in some
societies, also aquatic animals. These new food production systems arose gradually
beginning about 11,000 years before the present and spreading to most of the Old
World by 4000 BCE (Harris 1996; Zeder 2008).
The earliest domesticated plants—cereals and pulses (leguminous grains), einkorn
and emmer wheat (
Triticum monococcum
and T.
turgidum
), barley (Hordeum
vulgare), lentils (
Lens culinaris
), peas (
Pisum sativum
), and chickpeas (
Cicer
arietinum
)—were cultivated as early as 8500 BCE, Chinese millet and rice between
7000 and 6000 BCE, New World squash by 8000 BCE, corn by 4500 BCE; and
l ax (
Linum usitatissimum
) was the i rst i ber crop (Zohary and Hopf 2000;
Kirch 2005 Abboe et al. 2009). Animal husbandry was dominated by cattle, water
