In which of these industries did wages fall in the 1920s science forums?

Farming fell first then consumer products and then banks and stock market.

Farming was first hit by world depression in the early 1920s due to overproduction for WWI and not readjusting into the 1920s. As the world could not afford and/or did not need US food, farmers were first to see a reduction of income which would begin to impact other industries connected to farmers.