threshers in fields

短編 Mkondo を読んでいます。米国人のWard Beachはタンザニアの女性と結婚し、その女性を連れてオハイオに帰ります。
She had come to Ohio: she had taken that final, extra step. Now what? she thought. Now what am I supposed to do? Turn back? By August--she had been there a year--she was sobbing at night. The Ohio sky had become a tangible weight, bending the stalk of her neck, loading down her shoulders. She slumped through the hours. Ward, anxious to try anything, drobe her out of the city: barns on hills, threshers in fields.
"threshers in fields" は何でしょう？　農機具の一種だと思いますが、分からないので辞書を見ます。
・Oxford English Dictionary: A person or machine that separates grain from the plants by beating.: Agriculture thrives on the other side of those hills; grain threshers reaping wheat, trucks full of tomatoes, cucumbers and watermelons.
・Merriam-Webster's Online Dictionary: one that threshes; especially threshing machine: a machine for separating grain crops into grain or seeds and straw
脱穀機ですね。都会に住んでいるので実物は見た事がありません。