Mine is soil. I've got a graduate degree in soil science.

The most popular opinion that is wrong is all of the common ones. Soil science takes 5 science disciplines ( bio, physics, Chem, plant nutrition, and soil development) and rolls them all into one.

Not all tillage is bad

Not all amendments are good or work

There is just such a big gap in common knowledge when it comes to this topic and a lot of 'experts'