fascinating story about the short-lived usage of copper gardening tools:

In the 1930s, Viktor Schauberger investigated Bulgaria's farming decline, noticing that areas using traditional wooden ploughs had better harvests than those using modern iron ploughs.

He theorized that iron machinery adversely affected soil water characteristics, depleting its power and reducing yields. He also noticed more slugs coming to the surface, which may be indicative of rust particulates in the soil.

Schauberger devised a copper plow, shaped like a shark cutting through water. This plow significantly increased harvests and improved quality. In fact, using copper tools produced so much food that farmers literally couldn't sell it all.

Despite the great success of the copper plow the Bulgarian government and the fertilizer industry successfully thwarted the propagation of copper tools.