History 104: Western Civilization since 1648
Lecture: 18th Century Society and Economy

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During the 18th century, the climate in Europe improved enormously as part of a global climate shift. Summers became warmer and drier, winters were warmer too. This led to a shift in agriculture.

medieval open-field system -> three-field rotation

The old system was based on a big open field, where the whole community farmed the same strips of land. The land was divided into strips (rather than squares) so that horses or oxen could pull the plow over a longer distance before having to turn, and every third or fourth strip was farmed for the landlord to pay for using the land. Since the same strips were planted with the same crops each year, this led to soil exhaustion as the same crops pulled the same nutrients out of the soil over and over. To help prevent soil exhaustion, peasants left strips or fields "fallow" (empty) each season, rotating their crops while the fallow fields "recovered" and became more fertile. This worked well but left one-half or one-third of good land unplanted at any one time of year.

Three-field rotation
  Field 1 Field 2 Field 3
1st year Fall:
wheat & rye
oats, peas, barley, beans, lentils
2nd year Fallow Fall:
wheat & rye
oats, peas, barley, beans, lentils
3rd year Spring:
oats, peas, barley, beans, lentils
Fallow Fall:
wheat & rye

nitrogen-producing crops

In the 18th century, thanks to farming innovators like Jethro Tull, crops like turnip and clover were added to the rotation. It was noticed that these crops seemed to help the soil replenish itself, and provide food for animals at the same time. Thus less land was left fallow. We now know that this is because crops like this are "nitrogen-fixing"; they take nitrogen from the air and put it into the soil through nodules on their roots. Nitrogen is the most important element for the growth of plant leaves. This thinking actually led to a four-field rotation that included nitrogen crops intentionally.

drawing showing potato plant, leaves above, potatoes below ground

the great potato

The other great change that caused an agricultural revolution during the 18th century was the common adoption of the potato. Potatoes, brought in from the New World, were easy to plant, even in soils that were sandy or rocky and had few nutrients. They produced tons of food for animals, and eventually humans were persuaded to eat them too. They provided healthful carbohydrates and even Vitamin C. You can see an illustration of the potato here: one piece of a single potato could produce 12-15 potatoes, a highly productive use of farmland, especially in places like Ireland where the sandy soil could grow little else.

2. Population Boom ->