According to a new research by archaeologists from the University of Gothenburg, inhabitants of a small Neolithic farming village located in modern-day Sweden may have used fertilizers 5,000 years ago.

Gothenburg archaeologists have spent many years studying the remains of a Stone Age settlement in Karleby outside the town of Falköping.

In the current study, the team has been able to identify parts of the diet of the Stone Age people by using remains of grains and other plants and some highly advanced analysis techniques.

“Our first task was to find so-called macrofossils, such as old weed seeds or pieces of grain. By analyzing macrofossils, we can learn a lot about Stone Age farming and how important farming was in relation to livestock ranching,” said Dr Tony Axelsson.

Another aim has been to collect 5,000-year-old food remains, including animal bone material from cattle, pigs and sheep.

“By studying the levels of isotopes in the bones, we can for example find out where the animals were raised, which in turn can give important information about their role in trade,” explained Dr Karl-Göran Sjögren.

The results of the first grain analysis reveal that both barley and wheat were farmed at the Karleby site. They also point to elevated levels of the Nitrogen-15 isotope.

Nitrogen-15 is used to trace mineral nitrogen compounds, particularly fertilizers, in the environment.

These elevated levels may indicate that fertilizers were used in the area of Karleby 5,000 years ago.

“We will continue our analyses both in the field and in the lab, and are hoping to find more macrofossils. Hopefully we’ll find some weed seeds, as they may help confirm that fertilizers were indeed used since the type of weeds found in a field can signal whether fertilizers or some other method was used,” Dr Axelsson concluded.