We used to farm with bird poop

How Peruvian boobies and other gross things helped spark an agricultural revolution that continues to this day.

Photo by author. Bird, in the factory, making fertilizer.

Every time humanity reaches the limits of growth, we find a new way to blow right past them.

We seem to remember a time not too long ago when farming was pure, natural, more… environmentally friendly. But it wasn’t. No one alive today could remember that time. It was longer ago than you think.

Don’t forget to brush your teeth

Justus von Liebig first discovered that removing crops from a field led to a reduction in nutrients.

See the best source of nutrients are those in the plant itself. When it dies it falls to the ground to become food for the seeds it left behind. When we eat those plants, we take the nutrients with us. For thousands of years, farmers fertilized their fields with human and animal urine and excrement, night soil, which closed the loop, bringing nitrogen and phosphorus back to the soil. They even collected and fermented human urine as a soil rejuvenator.

Oh, you think that’s gross? Just as today ammonia is a handy cleaning product, fermented urine was used to wash clothes, remove rust, and even used to clean teeth.