Power for Technology: Animals

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Power for Technology: Animals


At the outset of the Middle Ages the basic power sources for most tasks were humans and animals. During the Middle Ages the harnessing of animals underwent changes that increased productivity by as much as 200 percent. Farming altered the natural environment to the benefit of humankind. Anything that improves the efficiency or productivity of agriculture benefits the entire civilization. During the medieval period, when 90 to 95 percent of the European population tilled the soil, farmers made the most important advances in agricultural technology of any era before the Industrial and Chemical Revolutions. These advances were predicated on the more efficient use of animal power.

Oxen versus Horses. The two main draft animals are oxen and horses. Oxen are strong and relatively easy to maintain, while horses are even stronger—and faster—but they are much more expensive to maintain than oxen. Oxen can graze on any grassy plant life, while horses can eat grass fodder, but to remain healthy and strong they also need a substantial proportion of prepared grains, particularly oats, in their diet. Oats were never the standard crop of ancient Europe because they are less prolific than wheat. But during the two centuries preceding the year 1000, changes in agricultural “machinery” and agricultural practice made it possible for European farmers to increase the yield of their crops, including oats. These changes—which seem to have happened almost simultaneously—were simple, but they had profound effects. Furthermore, although any one of them would have been beneficial by itself, as a combined system of agriculture they had a profound effect on Europe in the Middle Ages.

The Moldboard Plow. During the medieval period farmers stopped using light scratch plows and turned to heavier moldboard plows. In the ancient world and even during the medieval period in the Mediterranean region, the scratch plow—basically a pointed stick, or plowshare, dragged behind a beast of burden—was used to break up the topsoil in the fields, and then seeds were scattered across the rough surface. The scratch plow did a sufficiently good job in the light and dry soils of Mediterranean countries, but seed losses to birds could be quite high. Still, that method worked quite well for thousands of years. As ancient civilizations spread north of the Alps, however, they encountered heavier, wetter soils that were hard, or impossible, to break up with scratch plows. The moldboard plow, which came into use in Northern Italy and the Rhine Valley around 700–800, was a response to these new challenges. It retains the vertical pointed stick, or “plowshare,” of the scratch plow, but it has two new parts, the “coulter” and the “moldboard.” The coulter, a horizontal metal knife attached to the bottom of the plowshare, was added to cut the soil horizontally at the bottom of the slit made by the plowshare. With the coulter, rather than a simple vertical slit in the soil, the moldboard plow made an L-shaped cut. This new plow gets its name from the moldboard—a large, curved piece of wood set behind the share and coulter—which was added to turn the soil up and out of the cut, flopping it over and to the side of the furrow. It created a trench of about 6–12 inches (15–30cm) deep, and with a second pass in the opposite direction, this furrow became a foot or more deep. Instead of breaking up only the top few inches of soil, the moldboard plow churned up deeper soils, bringing more nutrients to the surface than the scratch plow and softening the compacted undersoil—thus giving the crops a better environment in which to grow.

Pulling the Moldboard Plow. Cutting this large amount of heavy soil took more power than one horse or ox could provide, so several animals had to be harnessed together to plow the fields. This need had a twofold consequence. First, since no single peasant was likely to own more than one or two animals, the need for teams of four, six, or eight animals resulted in the development of farming collectives, in which people of the same village shared their animals to everyone’s mutual benefit. Second, these large teams were extremely difficult to turn around, so the square fields that had been common in the days of lighter plows gave way to long, narrow strips of land that allowed farmers to minimize the number of times they had to turn their teams while plowing furrows. Determining the length of these long narrow fields resulted in the establishment of the furlong, a unit of measurement equal to 660 feet.

The Padded Horse Collar. With this new plough came a change in the harnessing of draft animals. In the ancient world an animal was harnessed by placing a flat leather strap around its front and up and over its shoulders. This sort of harness was tolerable for oxen, but its breast straps tended to strangle horses. The harder they pulled, the more their windpipes were crushed, which is why during the late Roman Empire edicts were issued limiting the weight of the load a horse’could pull. The problem was solved by adapting the ox yoke, which rests on an ox’s shoulders. Because a horse’s shoulders are not nearly as pronounced as an ox’s, the U-shaped ox yoke became an O-shaped padded collar that fits over the horse’s head and lies across its chest. The padded horse collar lets horses pull with all their strength and without the danger of strangulation.

Horseshoes. Another seemingly simple development had appeared around 500–600: the humble horseshoe. The Romans seem to have used a form of sandal to protect their horses’ hooves, and in the relatively dry climate of the Mediterranean region, these hoof coverings were not regularly needed. In the wetter climate of northern Europe, however, horses’ hooves are much more prone to rot, causing crippling damage. Nailing iron horseshoes to horses’ hooves not only keeps them a bit above wet ground, keeping them drier, but also provides horses with additional traction, just as modern shoes allow people to walk or run faster and harder than they can barefoot. Taken together, a horse collar and horseshoes increased a horse’s pulling capacity up to two or three times.

The Three-Field System. As European farmers began to benefit from using the moldboard plow and more efficiently harnessed horses, the organization of farming underwent a deceptively simple, yet profoundly important, revolution. Some time around 900–1000 farmers moved from what was called the two-field system of crop rotation to a new three-field system. Ancient and early medieval farmers did not usually spread fertilizer over their fields as modern farmers do. For this reason their fields needed time to recover their fertility after bearing a crop. Under the two-field system, a farmer divided his land roughly in half and farmed only one half of it in any given year, leaving the other part fallow (unplanted) to allow the soil to replenish its natural nutrients. For example, in year one a farmer might plant the west side of his property with the

standard crop of winter wheat, letting it grow from December until July. The following December, he would plant the eastern half of his property, leaving the west side fallow. The three-field system made the planting cycle a bit more complex. For example, in year one the farmer might plant one third of his land with winter wheat in December, plant another third with a summer crop in April, and let the last third remain fallow. The next year he would rotate, leaving the winter-wheat field of previous year fallow, planting wheat on the field where he had grown a summer crop, and planting his summer crop on the fallow land of the previous year. One more year of planting completed the rotation. Farmers also discovered that whatever crop-rotation system they used, it was worthwhile to plow their fallow fields twice a year to keep weeds down and to till in the manure left there by the animals that they put out to pasture on that land. This practice marked the beginning of regular, large-scale fertilization, which not only increased crop yields but also permitted farmers to keep larger herds of livestock.

Increased Productivity. The use of three-field farming increased crop sizes by 50 to 75 percent, depending on the system of measurement, and actually decreased labor. Consider the same six-hundred-acre farm under the two systems. Under the two-field system the farmer would plow 300 acres for a crop once a year and 300 acres of fallow twice a year for a total of 900 acres of plowing each year. Under the three-field system, the same farmer would have plowed 200 acres once for the winter crop, 200 acres once for the summer crop, and 200 fallow acres twice, for a total of only 800 acres of plowing each year. While saving himself from 100 acres of plowing, the farmer would also increase the area of his land under cultivation from 300 to 400 acres. Under the three-field system he would plow 800 acres for 400 acres of crops, or 2 plowed acres per acre of yield. With the two-field system he would have plowed 900 acres for 300 acres of crops, or 3 plowed acres per acre of yield. Medieval farmers who used the three-field system, in effect, increased their efficiency by 50 percent.

Increased Use of Crop Lands. At the same time, if a farmer had the time and available labor to plow 900 acres a year, the three-field system allowed him to put another 75 acres under cultivation, plowing 25 acres in the winter, 25 in the spring, and 25 more fallow acres twice during the year. So for the same amount of work he did under the two-field system, he could grow 650 acres of crops for 900 acres of plowing, dropping his plowed-land to crop-yield ratio to 1.38. As yet another benefit of the three-field system, his 900 acres of plowing were spread out more evenly throughout the year. If he had been able to plow 300 acres in one season before, he could still do so under the new system. Now—with the same manpower and available land—he could increase the size of his farm to 900 acres (with 300 + 300 acres planted in crops and 300 acres fallow). Taken together, the organizational changes in the medieval agricultural system increased productivity by as much as 200 percent.

New Crops. The new spring crops that were added when medieval farmers moved to the three-field system had other benefits as well. While wheat remained the staple crop for winter fields, the spring crops tended to include things such as peas, beans, oats, and rye. Not only did they add variety and nutritional value to the medieval diet, but they were also beneficial to the soil. Peas and beans in particular are called nitrogen-fixing plants. Since nitrogen is an important element for soil fertility, farmers who grew these plants further enhanced the benefits derived from the manure of their pastured livestock. Oats grow better in deeply plowed, well-fertilized lands, so they were grown more widely, providing food for the iron-shod and O-collared horses pulling the new plows, so oats supported that which supported them. Ultimately, all these innovations taken together formed a large, mutual-support system in which the sum of the whole was greater than the sum of the parts. The massive reorganization of the medieval agricultural system resulted in population growth and better health for people and animals. Furthermore, it sparked economic growth: as more crops became available for sale and more land came under cultivation, more taxes went to landlords, who could then use that money for commercial and industrial ventures, which were also supported by the growing population. The story of the Middle Ages in Europe is the story of an upward spiral in wealth, health, and productivity—one that was set back, not stopped, by the Black Death, and one that resulted in the population of Europe spreading out over the entire world.


Grenville Astill and John Langdon, eds., Medieval Farming and Technology: the Impact of Agricultural Change in Northwest Europe (Leiden & New York: Brill, 1997).

Del Sweeney, ed., Agriculture in the Middle Ages: Technology, Practice, and Representation (Philadelphia: University of Pennsylvania Press, 1995).

Lynn White Jr., Medieval Technology and Social Change (New York: Oxford University Press, 1962).