The BBC reports that researchers at the University of Oxford are claiming that our Neolithic ancestors may have used manure to fertilize their farms almost 8,000 years ago.
Scientists analyzing the charred remains of Stone Age crops found the plants to contain high levels of N15 nitrogen, the same chemical found in manure.
This study could provide valuable clues as to what our ancestors ate and how they lived. Any evidence that indicates a transition to sustained farming implies an abandonment of earlier nomadic behavior in favor of settlements. The practice of fertilization implies a long-term investment in the land, one that traveling nomadic peoples would have been unlikely to make.
The team, led by Amy Bogaard, believes that this protection and cultivation of stable farmland could show the beginnings of our social system. If land was preserved for future generations, it would likely have been viewed as a commodity, thus starting what the researchers refer to as the system of "the haves and the have-nots."
However, science cannot yet say for sure if this manuring was intentional, or if the levels of N15 nitrogen in the soil were definitively caused by manure and not other environmental factors such as rain or high temperatures.