Preventing Soil Exhaustion In The Middle Ages – 2 inventions!

Peasants made up roughly 80% of the population in medieval Western Europe. Their job was to work the fields and the fruits of their labor were the foundation on top of which everything we commonly associate with the Middle Ages like knights and castles was built.

But despite them making up the vast majority of the medieval population and their highly important work that created the foundation for everything we usually think of in regards to the Middle Ages, the common peasant, and his work is rarely talked about.

So in this article, I would like to present who the medieval peasants were, how they worked, and how they managed to prevent soil exhaustion.

The moldboard plow and the 3-field system were used by medieval farmers to maintain the soil fertility of their fields and prevent soil exhaustion. In the 3-field system, the farmland is split into 3 parcels. One is planted with nitrogen-consuming crops like bread wheat. The second is left fallow and is plowed at the end of the year with the mouldboard plow. The third is planted with legumes that enrich the soil with nitrogen. Each year the plants are rotated so that bread wheat is only planted on the first parcel in the fourth year again.

Let`s take a closer look!

Who worked in the fields in the Middle Ages?

While today the word peasant might hold some negative connotation that was not the case in the Middle Ages. In the Middle Ages, a peasant was simply a farmer and about 80% of the population were peasants. It is also important to remember that not every medieval peasant was dirt poor, especially those who owned their own ground and who had a talent for trade (especially producing and trading wool, but also beer was extremely lucrative in medieval England) could accumulate a very decent level of wealth.

Aside from the class of land-owning peasants, there were also serfs, unfree peasants who worked the land that they rented from a landlord and that they could not leave without permission. Serfs can almost be seen as a part of the landlords’ property.

But the serfs being part of the landlords’ property also had another side to it.

While the serfs were not allowed to leave their parcel without permission their landlord was also not allowed to just kick them off his property. Indeed most of the serfs were working on land that had been rented by their families for several generations.

When it comes to the social background of these medieval landlords then we can find a fast variety. Some were knights who had to rely on the income from their land to make a living since training their skills as warriors did not allow them to have a job.

Others were monasteries, where the monks were also too busy praying as if they could work the vast estates that many monasteries accumulated over time. But there were also wealthy peasants who rented parts of their estates to families of serfs who would then work these fields and pay them rent.

By the way. These medieval fields looked nothing like the fields that you can see when you drive through modern-day England. Today there is the so-called enclosed farming in which the fields and pastures are divided by fences and each field that is enclosed with a fence is generally owned by one farmer.

In the Middle Ages, the landlords rented their land to their peasants and serfs in the so-called open-field system. The medieval open-field system meant that the fields of the individual peasants and serfs were not separated by fences. Instead, there were three big fields on which each serf and peasant had a selion, a narrow strip of land, that he worked and for which he paid an annual rent to his landlord. Additionally, there were also grazing areas that were communally used.

And the division of the available farming land into 3 fields actually brings us to the first medieval innovation with which medieval farmers could successfully prevent soil exhaustion.

Let`s take a look!

How did medieval farms prevent the problem of soil exhaustion?

When it comes to maintaining the fertility of the soil the main concern was (and still is) the need to maintain an adequate level of nitrogen in the soil. Especially plants like bread wheat that were bred with the goal of maximizing the harvests exhaust the soil since they consume large amounts of nitrogen.

So when no additional measures were taken and wheat was planted repeatedly each year on the same piece of land then the soil lost its fertility and the harvests shrank. That problem was not new, the Romans had already developed a 2-field system in which only one field was worked while the other one was left fallow so that the soil fertility could regenerate.

However, Rome still had to import most of its bread wheat from outside of Italy even though the Italian soil, especially in Northern Italy and Campania, was more than fertile enough to grow wheat. Do you want to find out why the Romans still preferred to import wheat instead of growing it and what plants they grew instead (and why they grew them)? Then I would like to recommend you my article here.

In the Middle Ages, the old Roman system of having two fields of which one was worked while the other one was left fallow was improved and the 3-field system was developed.

The 3-field system: A medieval innovation

As mentioned, the Romans had split their farmland into two fields.

One of them was used to plant bread wheat or other crops while the other one was left fallow. Different weeds were allowed to grow on that fallow parcel and farm animals were put on the land so that their droppings fertilized the soil. At the end of the year, the fallow parcel was then plowed up which brought the weeds and the animal droppings into the soil and acted as fertilizer.

So. In ancient Roman times, the two parcels in which the available farmland was split were worked in rotation so that each piece of land was only planted with crops that consumed large amounts of nitrogen every two years. That is called the two-field system.

That system was then improved in the Middle Ages.

It turned out that some plants like bread wheat and other crops consume large amounts of nitrogen out of the soil. But other plants like legumes (beans, peas, and so on) enrich the soil with nitrogen. So a new cycle was adopted in which the available farmland was split into 3 parcels.

The 3-field system splits the available farmland into 3 parcels. The first is planted with bread wheat or other crops that consume lots of nitrogen from the soil. The second is left fallow and used as a grazing ground for farm animals that fertilize the ground with their droppings. On the third parcel, legumes (beans and peas) that enriched the soil with nitrogen are planted. Each year the planted fruits were rotated so that the same fruit was only planted every four years onto the same parcel.

The system was genius.

After the nitrogen-consuming bread wheat had been planted and harvested in the first year the parcel was left fallow for one year. During that year weeds grew on the parcel that was used for grazing farm animals which left droppings. At the end of the second year the heavy plow, also a medieval invention that we will talk about in a minute, was used to plow both the weeds and the animal droppings under.

And in the third year, the ground in which the plowed under weeds and animal droppings were still rotting and fertilizing the soil, the parcel was planted with legumes that enriched the soil with the nitrogen that had been lost in year number one when bread wheat was grown.

So in year number four, the soil fertility had been fully restored and bread wheat could be planted again.

That system was highly effective in maintaining the fertility of the soil, but it had one big disadvantage. Since each parcel could only be planted with bread wheat every 4th year a lot more farmland was necessary than during the Roman period when bread wheat could be planted on a parcel every two years.

As a result, more and more land had to be cultivated. And that brings us to one of the tools that was invented in the Middle Ages and that made the expansion of farmland possible in the first place.

The heavy plow: Ideal for plowing the heavy clay-rich soil of Western & Northern Europe

When we look at farming in medieval Western Europe then we have to consider the type of soil most prevalent. While most of the territories of the Roman Empire in which the agricultural hubs of Antiquity were situated show a pretty light and sandy soil the soil most prevalent in England and the more Northern parts of medieval Western Europe consisted of heavy clay-rich soil.

But why am I telling you that in regards to plowing?

Well, because the simple scratch plow that the Romans used (the ard) was only suited for light and sandy soil but was overwhelmed when faced with heavy clay-rich soil. It was also not suited for clearing new land or plowing under grass.

But especially the last part, being able to plow under the grass that grew on the parcels during the fallow period, was essential for the function of the 3-field system!

So around the year 1,000 AD, the heavy plow (as well as the Mouldboard plow) was developed and its use spread over Western Europe. Both plows were able to plow through the heavy clay-rich soil and were suited to plow deep enough that the weeds and animal droppings left from the fallow period could be incorporated into the field where they acted as fertilizer,

However, there was one downside that led to another important invention.

The heavy plow is kind of heavy (Big surprise, I know). So teams of oxen were used to pull the plow with the help of yokes. But while oxen – contrary to horses – could be fed on grass alone they were pretty slow.

And in the 12th century, the first horse collars that allowed horses to be used as draft animals without suffocating them surfaced in Western Europe. However despite horses being much faster they did not really threaten the role that oxen as draft animals played in agriculture until the 19th century and in some parts of the world even until today.

But the ability of horses to move plows or more commonly carts much faster than oxen was not only important in agriculture but especially in warfare since the baggage trains that supplied a medieval army also had to be pulled by either oxen or horses. Both draft animals had their advantages and disadvantages.

For example, carts that were pulled by oxen slowed down the army. But contrary to horses oxen could be fed on grass alone. So additional feed grain for the draft animals only had to be hauled along when the carts of the baggage trains were pulled by horses. And that not only drastically limited the amount of equipment that could be transported on the carts but also the reach of the baggage train.

For more information on that and how the logistics of medieval warfare worked in general I would like to recommend you my article here.

And here you can find out more about what medieval peasants wore.

Take care of yourself because you deserve it. You really do.

Until next time

Yours truly

Luke Reitzer


Ernst Schubert: Essen und Trinken im Mittelalter (Darmstadt 2006).

Frances and Josheph Gies: Life in a medieval village (2016).