What was a cause of decreased demand for food in the 1920s?

According some author the cause was  the  decline of agriculture.

Explanation:

The decline of agriculture in 1920 had different causes as:

1)Overproduction.  It was linked with by several others factors like overly efficient machines.  

2)Governments polices. US in that time was trying to sell its abundance of goods to foreign countries.

3)New Machinery. The new technology that was invented such as tractors produced that farmers losing their jobs.  

4)The effects of World War I. It was not directly but after an efficient context it was start to decline.  

I would say  increased farming income

Explanation:

Makes the most since.

disequilibrium means that either supply is greater than the demand for an available good, or that the demand for a product outstrips the available supply. it implies that the price for a is either too low creating large demand, or too high creating a large surplus of supply.