Planting fish!

[redietz]

When the Pilgrims came to the New World, a Local Native Americans showed the Pilgrims how to enrich the soil using fish for their crops...

Interesting enough that particular Native American (Tisquantum aka "Squanto") had previously lived in Europe for seven years (both England and Italy) and had learned that trick there. The local tribe didn't do that -- although they planted corn and bean together so that the beans would enrich the soil, while at the same time using the corn stalks as bean poles.

Using fish as fertilizer was apparently standard practice in Europe, but the Pilgrims were city dwellers who knew nothing about farming. (Nor, apparently, did they question why Squanto already happened to speak English.)