Ancient farmers manured the land
17 July 2013, by Tom Marshall
Europe's first farmers used sophisticated muckspreading techniques to keep their land fertile some eight millennia ago, according to new research. And this revolution in agriculture may have played an important part in the genesis of the violence between communities that's blighted human society ever since.
It seems people were manuring and watering their crops as long as 6000BC. Until recently, the consensus has been that farmers only started using animal dung during Iron Age or Roman times, and that more ancient farmers of the Neolithic used a slash-and-burn approach involving working a patch of land for a few years and then moving on once they'd exhausted its nutrients.
But a team of researchers has analysed charred pulse seeds and cereal grains from 13 Neolithic sites around Europe, looking at the relative proportions of several different forms of nitrogen, known as isotopes. They looked in particular at the relative abundance of the heavier nitrogen-15 isotope relative to its lighter sibling nitrogen-14.
'There was a lot of violence in these early farming communities - they weren't peaceful hippie types.'
Dr Amy Bogaard, University of Oxford
Experiments on modern farms show that the more muck you spread on a field, and the more often you do it, the higher the ratio of N-15 to N-14 climbs. In crops across Europe, the paper's authors found clear evidence of that the locals were spreading the dung of goats, cattle, sheep and pigs on their fields much earlier than we'd assumed.
This suggests they understood how important the land's fertility was and tried to preserve or even increase it for the next generation, having noticed that animal dung let them grow bigger, healthier plants. This involved long-term investments of the time and effort needed to collect, transport and spread manure that would then slowly release its nutrients over years and decades.
This could have led to important social transformations; as farmers started to pass down fertile land to their children, some of the earliest divisions between rich and poor might have started to emerge. If heavy manuring had made one group's land unusually fertile, their neighbours might have been tempted to resort to violence to get it.
'The fact that farmers made long-term investments such as manuring their land sheds new light on the nature of the early farming landscapes in Neolithic times ,' says Dr Amy Bogaard, an archaeologist at the University of Oxford and lead author of the paper, published in Proceedings of the National Academy of Sciences.
'The idea that farmland could be cared for by the same family for generations seems quite an advanced notion, but rich fertile land would have been viewed as extremely valuable for growing crops,' she adds. 'We believe that as land was viewed as a commodity to be inherited, social differences in early European farming communities started to emerge between the haves and the have-nots.'
She cites the example of the Neolithic mass burial at Talheim in Germany, which holds the remains of a whole community who were massacred – men, women and children – with blows to the head from the stone axes that farmers used to clear land, arguing that this could have resulted from a raid intended to seize the community's land. 'We're increasingly realising that there was a lot of violence in these early farming communities - they weren't peaceful hippie types,' says Bogaard. 'Some of that violence was probably in the form of sporting or ritual contests between communities. But some of it was very deadly, like what we see at Talheim, where it looks like the attackers went in by night and killed everyone.'
The 124 samples of charred barley, wheat, lentils and peas the team examined came from harvested crops that were stored in buildings that then burned down. They came from sites dating from between 6000BC and 2400BC, and are taken from places across Europe including Hambledon Hill in Dorset and Lismore Fields in Derbyshire.
The NERC-funded study even suggests farmers understood which crops would benefit most from manure and concentrated their resources on them, leaving relatively hardy crops unfertilised; in one site in southern Greece, naked wheat had been heavily manured while barley had received very little fertilisation. Pulse crops, meanwhile, had received both manure and lots of water. 'Subsistence farmers are very observant of what we would see as very small differences in plant growth,' Bogaard explains. 'They would have noticed quickly that their middens and dung heaps produced much bigger, healthier plants, and later realised that certain crops benefited more from manure than others.'
Crop manuring and intensive land management by Europe's first farmers. Amy Bogaard, Rebecca Fraser, Tim H. E. Heaton, Michael Wallace, Petra Vaiglova, Michael Charles, Glynis Jones, Richard P. Evershed, Amy K. Styring, Niels H. Andersen, Rose-Marie Arbogast, László Bartosiewicz, Armelle Gardeisen, Marie Kanstrup, Ursula Maier, Elena Marinova, Lazar Ninov, Marguerita Schäfer, and Elisabeth Stephan. PNAS 2013 : 1305918110v1-201305918.
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