David Dunham Page | Facts
0.75 g of protein/kg of body mass/day [Marvin Harris, The Sacred Cow and the Abominable Pig]
| Hunter-Gatherer | 0.1 person / km2 |
| Dry Farming | 1-2 person / km2 |
| Irrigation | 6-12 person / km2 |
“One can still harvest up to seven hundred pounds of grain per acre from wild wheat growing naturally on hillsides in the Near East. In a few weeks a family could harvest enough to feed itself for a year.” [Jared Diamond, The Third Chimpanzee]
“The typical yield ratio in medieval Europe as 1:3 or at best 1:4, the minimum yields which make agriculture worth while and create conditions of sustaining life. ... In the late Middle Ages, western yields rose to 1:5, and then, in the course of the sixteenth and seventeenth centuries, they improved further to 1:6 and 1:7. ... Like the rest of Europe, Russia averaged in the Middle Ages ratios of 1:3, but unlike the west, it did not experience any improvements in yield ratios during the centuries that followed. In the nineteenth century, Russian yields remained substantially the same as they had been in the fifteenth, declining in bad years to 1:2, going up in good ones to 1:4 and even 1:5, but averaging over the centuries 1:3 ... Such a ratio generally sufficed to support life. ... The trouble with Russian agriculture was not that it could not feed its cultivators but that it never could produce a significant surplus. ... By the end of the nineteenth century, when good German farms regularly obtained in excess of one ton of cereals from an acre of land, Russian farms could barely manage to reach six hundred pounds.”
In the 1840s, August Haxthausen “compared the income produced by two hypothetical farms of equal size, 1000 hectares of arable land and meadow each, one located on the Rhine, near Mainz, the other on the upper Volga, in the vicinity of Iaroslavl. A German farm of this size, in his estimation, would require the regular attention of 8 male and 6 female peasants, 1500 man-days of seasonal hired labour and 4 teams of horses. The total operating expenses would come to 3500 thalers. With an estimated gross income of 8500 thalers, it would return annually a net profit of 5000 thalers. In Iaroslavl, only because the short farming season demands a heavier concentration of labour, it would take 14 male and 10 female peasants, 2100 man-days of hired labor, and 7 teams of horses to accomplish the same work. The resulting expenses would reduce the profit by nearly a half, down to 2600 thalers.”
The sokha, the Russian scratch plow, penetrated at most 10 cm, but required little pulling power and was ten times as fast as the plow. [Richard Pipes, Russia Under the Old Regime]
The hunter-gatherers of the Chathams had 5 people per square mile, Hawaii had 300, and Anuta had 1100 people per square mile -- a greater density than modern Holland. [Jared Diamond, Guns, Germs, and Steel]
“A single Inuit whaling crew expected to capture a dozen or more whales in a season; and since each whale weighed several tons, their catch sufficed to support hundreds of persons.”
“Modern harvest to seed ratios for rice are as much as 100:1 even when using traditional methods, whereas in medieval Europe a yield of 6:1 for wheat was exceptionally high. On the other hand, rice cultivation was (or became) more laborious than Southwest Asian grain agriculture.”
“The caloric yield per acre of both maize and potatoes almost matches paddy rice and far exceeds what wheat and barley can provide.”
The spread of maize “was slowed by the fact that maize had to adjust genetically to different day lengths in different latitudes before it could ripen with the seasons.”
In western Europe, “By dividing arable land into three fields — one sown in autumn for harvest in late spring, one sown in spring for autumn harvest, and one left fallow to be plowed (for weed control) in summertime — plow teams could work almost year round. they interrupted the task only for the twelve days of Christmas and ruing the weeks when planting and harvesting required everyone’s urgent effort. This regime allowed a single plowman’s share of cultivated land to amount to about thirty acres — far more than was needed to feed his domestic animals, himself, and his family. By comparison, in Mediterranean lands a single family could only keep about ten acres under cultivation, because grapes and olives had to be hoed by hand, and grainfields could only be plowed during a few weeks of the year after the first autumn rains had softened sun-baked soils and before it was time to plant for harvest in the spring.”
Maize “yielded about nine times as much grain (per unit of labor) as either millet or sorghum.” The starchy tubers of cassava, or manioc, “could keep for as long as two years underground. In the violent context of tropical Africa during the seventeenth and eighteenth centuries, keeping one’s food underground rather than where it might be seized by raiders often made sense. Moreover, cassava yielded as many calories per acre as rice or maize (twice as many as wheat).” [J. R. McNeill and William H. McNeill, The Human Web]