Humans used fertilisers 5,000 years ago: study

New excavations in Sweden indicate that fertilisers may not be a modern innovation but were already in use some 5,000 years ago during the Stone Age.
Researchers from the University of Gothenburg, Sweden are studying the remains of a Stone Age community in Karleby outside the town of Falkoping, Sweden.
Scientists who were trying to identify parts of the inhabitants' diet, in the results of their first analyses, found evidence that fertilisers were used already during the Scandinavian Stone Age.
Using remains of grains and other plants and some highly advanced analysis techniques, the two researchers and archaeologists Tony Axelsson and Karl-Goran Sjogren have been able to identify parts of the diet of their Stone Age ancestors.

"Our first task was to find so-called macrofossils, such as old weed seeds or pieces of grain. By analysing macrofossils, we can learn a lot about Stone Age farming and how important farming was in relation to livestock ranching," said Axelsson.
They collected animal bone material - or simply 5,000 year old food remains. Pieces of bones from cattle, pigs and sheep were collected from the site.

"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," said Sjogren.

The results of the first grain analyses, besides revealing that both barley and wheat were farmed at the site, also pointed to elevated levels of the isotope N15 (nitrogen 15).
The elevated levels may indicate that fertilisers were used in the area of Karleby already 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 fertilisers were indeed used since the type of weeds found in a field can signal whether fertilisers or some other method was used," said Axelsson.