If you think the future of crop production means ever-wider equipment pulled by ever-bigger tractors, think again.

Self-driving so-called autonomous vehicles could change the face of crop production and resurrect machinery sizes common on farms 75 years ago. Instead of 500-hp tractors and 48-row planters, think of fleets of small power units pulling narrow implements with the combined capacity of today’s behemoths. Payoffs will include higher yields, reduced labor costs and greater overall productivity.

That’s the vision of Scott Shearer, a precision ag researcher and head of the Food, Agricultural and Biological Engineering Department at Ohio State University.

“I could see us going to fleets of small vehicles that have a gross vehicle weight of between 5,000 and 7,500 lbs. — a 50-horse vehicle,” he says. They’ll be pulling narrow implements; think four-row planters and 20-ft. spray booms.

The shift to small and narrow made possible by autonomous tractors will be driven by several factors, including labor savings. But yield gains made possible by reducing soil compaction may be more important, Shearer says. Although compaction-related yield increases will vary, 5 to 7% improvements may be realistic in many cases, providing a big impetus for change.

“Today, farmers are living with the negative impact of compaction on crop yields caused by heavier farm machinery,” Shearer says. “By going to a lighter autonomous machine, the profit we are going to capture from reduced soil compaction may dwarf the savings from labor. Yield gains will likely offset concerns over lower fuel efficiency from smaller tractors.”

In Shearer’s autonomous-vehicle future, tractors will be have a much shorter service life than today’s norm — perhaps as little as 5,000 hrs. So upgrading to the latest technology won’t mean trading off a vehicle with decades of remaining service life. As a side benefit, keeping these smaller, lower-hours machines up and running may be easier compared to servicing today’s more complex machines. Field repairs for all machine components will be possible from the back of a pickup.

“If you have a throwaway vehicle that you can recycle after a few years, that changes the equation,” Shearer says. “What I’m suggesting is that in the future the time between purchase and technical obsolescence will need to match up with mechanical life. Much of the up-front costs will be in the controls, not the iron.”

The move toward smaller autonomous vehicles will spur precision technologies, Shearer says. In particular, by-the-row and by-the-nozzle controls will be more practical than with today’s wider machines. More attention to precise planting could evolve as manufacturers focus less on massive frames needed to carry dozens of row units and more on the planting units themselves, he adds.

Shearer is uncertain about the timetable for widespread adoption of autonomous vehicles or how quickly farmers and manufacturers will shift from high- to low-horsepower tractors and narrower field equipment. “It is going to be a transition over time,” he says.

But with the new autonomous systems coming on the market this year, the evolution is under way.