What were the results of Hortense Powdermaker's study of the Deep South’s sharecropping system of the 1930s as noted in the nonfiction book, The Warmth of Other Suns?

Hortense Powdermaker was an anthropologist who studied the Deep South’s sharecropping system of the 1930s. She concluded that only 25% of the sharecroppers got the “share” that they had earned.