Read Online Plagues and Peoples by William H. McNeill - Free Book Online Page A
Authors: William H. McNeill
Tags: 20th Century, Non-Fiction, European History, Plague, Medieval History, Biological History, Social History, Cultural History, v.5, disease, Medical History
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species:
Homo sapiens
.
Shortening natural food chains involved humankind in never-ending effort. Protecting herds and crops from animal predators was not a serious problem for skilled hunters, though it required perpetual vigilance. Protection from other men, however, was a different matter, and efforts to achieve safety from human marauders provided the chief stimulus to political organization—a process by no means completed yet.
More significant for human life, because it involved more continual effort by a larger proportion of the entire population, was the work of reducing weeds, i.e., trying to eliminate rival species competing with domesticated varieties of plants and animals for living space. Weeding by hand may indeed have been the first form of “agriculture,” but human powers achieved a new range when people learned how to remodel natural environments more radically, widening the ecological niche available to their preferred crops by eliminating natural climax vegetation. Two methods proved effective: artificial flooding of land naturally dry, and mechanical alteration of soil surfaces by digging and plowing.
Flooding allowed humans to drown out the competing species. When the agricultural year could be arranged so that part of the time fields lay under water while at other times the water was allowed to run off so that the land dried out, weedswere not much of a problem. Few plant species could thrive under alternating extreme conditions of wet and dry; fewer still could survive when farmers deliberately adjusted periods of flood and drought to suit the needs of the desired crop by simply opening and closing cunningly arranged sluices. Of course, only crops that flourish under shallow water benefited by such a regime: rice above all. But other less valuable root crops can be raised in this fashion also.
The mechanical disturbance of soil by digging-stick, hoe, spade, or plow is far more familiar to Westerners, since this was the type of agriculture that established itself in the ancient Near East and spread thence to Europe. It also prevailed at the other centers of early agricultural development in the Americas and Africa. An initial phase—slash-and-burn cultivation—depended on destroying deciduous forest by girdling the trees. This allowed sunlight to flood the forest floor and sustain the growth of grains in an environment from which competing grasses were absent. This style of cultivation, however, even when supplemented by burning the dead trees and scattering ashes on the soil to renew fertility, was not stable. Air-borne seeds soon established a lush growth of thistles and similar weeds in forest clearings. Given a year or two in which to establish themselves, these intruders were fully capable of crowding out the crop. Only by moving on to start anew with a first year’s weed-free crop on virgin land could the most ancient Near Eastern, Amerindian, and African farmers keep going.
These initial limitations were transcended in the ancient Near East by the invention of plowing, not long before 3000 B.C . Plowing allowed effective weed control, year in and year out, so that fields could be cultivated indefinitely. The secret was simple. By substituting animal for human muscles, the plow allowed ancient Near Eastern farmers to cultivate twice the area they needed for cropland, so that when the extra land was fallowed (i.e., plowed during the growing season so as to destroy weeds before seeds had formed), it created a suitably empty ecological niche into which next year’s crop mightsafely move without being too severely infested by locally formidable weed species.
It is a testimony to humanity’s animistic propensities that most textbooks still explain how fallowing allows the earth to restore fertility by having a rest. A moment’s thought will convince anyone that whatever processes a geological weathering and consequent chemical change occur in a single season would make no noticeable
Homo sapiens
.
Shortening natural food chains involved humankind in never-ending effort. Protecting herds and crops from animal predators was not a serious problem for skilled hunters, though it required perpetual vigilance. Protection from other men, however, was a different matter, and efforts to achieve safety from human marauders provided the chief stimulus to political organization—a process by no means completed yet.
More significant for human life, because it involved more continual effort by a larger proportion of the entire population, was the work of reducing weeds, i.e., trying to eliminate rival species competing with domesticated varieties of plants and animals for living space. Weeding by hand may indeed have been the first form of “agriculture,” but human powers achieved a new range when people learned how to remodel natural environments more radically, widening the ecological niche available to their preferred crops by eliminating natural climax vegetation. Two methods proved effective: artificial flooding of land naturally dry, and mechanical alteration of soil surfaces by digging and plowing.
Flooding allowed humans to drown out the competing species. When the agricultural year could be arranged so that part of the time fields lay under water while at other times the water was allowed to run off so that the land dried out, weedswere not much of a problem. Few plant species could thrive under alternating extreme conditions of wet and dry; fewer still could survive when farmers deliberately adjusted periods of flood and drought to suit the needs of the desired crop by simply opening and closing cunningly arranged sluices. Of course, only crops that flourish under shallow water benefited by such a regime: rice above all. But other less valuable root crops can be raised in this fashion also.
The mechanical disturbance of soil by digging-stick, hoe, spade, or plow is far more familiar to Westerners, since this was the type of agriculture that established itself in the ancient Near East and spread thence to Europe. It also prevailed at the other centers of early agricultural development in the Americas and Africa. An initial phase—slash-and-burn cultivation—depended on destroying deciduous forest by girdling the trees. This allowed sunlight to flood the forest floor and sustain the growth of grains in an environment from which competing grasses were absent. This style of cultivation, however, even when supplemented by burning the dead trees and scattering ashes on the soil to renew fertility, was not stable. Air-borne seeds soon established a lush growth of thistles and similar weeds in forest clearings. Given a year or two in which to establish themselves, these intruders were fully capable of crowding out the crop. Only by moving on to start anew with a first year’s weed-free crop on virgin land could the most ancient Near Eastern, Amerindian, and African farmers keep going.
These initial limitations were transcended in the ancient Near East by the invention of plowing, not long before 3000 B.C . Plowing allowed effective weed control, year in and year out, so that fields could be cultivated indefinitely. The secret was simple. By substituting animal for human muscles, the plow allowed ancient Near Eastern farmers to cultivate twice the area they needed for cropland, so that when the extra land was fallowed (i.e., plowed during the growing season so as to destroy weeds before seeds had formed), it created a suitably empty ecological niche into which next year’s crop mightsafely move without being too severely infested by locally formidable weed species.
It is a testimony to humanity’s animistic propensities that most textbooks still explain how fallowing allows the earth to restore fertility by having a rest. A moment’s thought will convince anyone that whatever processes a geological weathering and consequent chemical change occur in a single season would make no noticeable
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