The World’s Oldest Fertilizer?

Europe’s first farmers spread across the continent, bringing with them the benefits of having
food sources readily available, at least most of the time.  But farming drains nutrients from the
soil, and without some means of replenishing those nutrients, eventually the soil wears out and
must be abandoned.


Up till now, the use of manure as fertilizer was thought to have begun about 3,000 years ago.
Now a new discovery indicates that farmers were using manure to fertilize their crops about
8,000 years ago. 

A team led by University of Oxford archaeobotanist Amy Bogaard sampled grains and pulses
such as peas and lentils from sites all over Europe and ranging in age from 7900 to 4400 years
old.  They were looking for the rare isotope nitrogen-15, which occurs in significantly higher
than normal quantities in manure.

The team studied 124 crop samples from 13 farming sites ranging in age from approximately
4400 to 7900 years and located in areas across Europe, such as Greece in the southeast and
Denmark in the northwest.  The team analyzed 124 crop samples and found that nitrogen levels
in all those samples were unusually high for wild grains, but consistent with results found in
plants which had been treated with animal fertilizer. 

There are at least two plausible theories to explain how the ancient farmers learned to fertilize
their fields.  One is based on the idea that observant farmers realized that seeds spread in areas
where a relatively heavy presence of animal fertilizer grew faster and stronger.  From those
observations, the farmers might originally have practiced a sort of “crop rotation,” moving their
animals and gardens every few years.  In other cases, once they discovered that manure
improved their crops, farmers might have deliberately saved the manure and worked it into their
garden soils.

No matter how they discovered the use of fertilizer, early farmers were able to extend the life of
their land, which allowed them to remain on the same land for a longer time.  This new
sedentary lifestyle permitted the development of larger families and social groups.  New
technologies, such as the expanded use of grain storage, seed development, and even cooking
techniques were made possible as farming lifestyles spread and became more sophisticated. 

Fertilizer is more important than many people may think it is.  Without it, farmers could not
produce the prolific crops that keep us all fed.  The need to periodically abandon unproductive
fields would limit the size of farms, and in areas all around the world, the abandoned land would
be subject to the devastating effects of windstorms and floods which create deserts and
unproductive badlands.  We should be grateful to those innovative farmers who discovered
fertilizer all those years ago.

There’s more information on the first fertilizers here: