Final answer:
Drought and poor land management practices led to the loss of vegetation and soil, resulting in massive dust storms that blew away vast quantities of topsoil.
Step-by-step explanation:
The Dust Bowl occurred in the 1930s in the US, particularly in the Southern Great Plains. The main cause of the loss of vegetation and soil was a combination of drought and poor land management practices. During this time, plowing exposed the soil to the sun and wind, causing it to dry out and turn to dust. The lack of vegetation and the intense winds led to massive dust storms that blew away vast quantities of topsoil, leaving the land barren and unproductive.