Which of the following actions or events did not contribute to the dust bowl? farmers in the central u. s. had plowed grasslands to grow food crops to feed the increasing human population. they left the fields plowed and bare in the winter months when crops were not grown, and this left the soil exposed to wind. a long drought in the 1930s left the exposed soil especially dry due to the lack of precipitation. with the advent of pesticides, minerals in the ground were leached.