ANSWER:
Replacing natural grasses with crops had the biggest impact on dust storms in 1930.
Step-by-step explanation:
- Farming had been extensively practiced in 1930s. The farmers ploughed the fields and grew a wide variety of crops that replaced the natural grasses.
- The natural grasses had the ability to keep the soil fixed and trapped not allowing it to be carried away easily by water or wind.
- The removal of natural grasses led to the erosion of the top-soil which eventually led to dust storms and massive destruction.