This post says big farms are more efficient when capital is important; small farms when labor is more important.
It makes intuitive sense: if you're doing small plots with hand tools, the expertise and attention of the tool wielder is important. If you're doing thousands of acress with equipment worth hundreds of thousands or millions of dollars, the ability of the tractor driver is less important than getting the most use out of the equipment.
Modern Farmer has a piece on John Deere's self-driving tractor, which really sounds like a package of software and sensors which can be added onto different tractors. Civil Eats has a longer piece on how the rising prices of farm land make it hard for beginning farmers, especially those of color, to set up an operation.
The two factors work together with others to make a vicious cycle. The higher the cost of entry by buying land and equipment the greater the premium for going big.
Since I don't get the hard copy version of Technology Review, I'm not sure whether it's one issue, but this is the notation they attach to the beginning of a number of posts on their website:
"This story is one of a series about how hidden innovations produce the foods we eat at the prices we pay."
"But I still have more crops than some of my neighbors, who sometimes recycle seeds and don’t have very much at all."
That one sentence seems to me to encapsulate the challenges for the small farm/food movement people. It points to an evolution over decades which will lead to modernized production ag growing the bulk of our calories, with smaller operations producing for the niches.
