John Fraser Hart.
The Land That Feeds Us.
New York: W. W. Norton & Company, 1991 (reprint 1993).
Book information: Amazon.com.

An introductory survey of the history, economics, geography and practice of agriculture in the United States, characterising regional farming practices in the East, Mid-West and South. Much of the book is based upon the author's visits to farms in 1958/1959 and again in 1982/1983, which illustrate his discussion of why particular patterns of farming occurred in each region and how those patterns changed over time due to economic and technological factors. (Those changes include: fewer farms with greater acreages; increased specialization; increased mechanization; greater yields per acre; less labor input per unit output.)