Why? Unless a farmer is working a perfectly square, very large field — say 1,000 acres or more — inefficiencies result, says Kastens. During his 15 year tenure at KSU, he worked for the university’s agricultural extension, serving as a consultant to farmers and farm equipment companies on speed and efficiency issues. He’s also now a full-time farmer.

“There’s no question you can lose (production) efficiency with larger equipment,” Kastens says. “I know it doesn’t sound right, but the only thing you generally gain is labor efficiency.

“Think about it this way,” he continues, “You make the outside two rounds to set yourself up for spraying or combining, for example. But after that, every time you make a pass, whether it’s a combine or a sprayer, you’re still driving into the headland to turn around — especially if you’re hitting it at an angle, which you most likely are. Plus, you may be even more limited by trees, creeks or other obstacles. In effect, you could say that the size of the fields hasn’t caught up with the size of the machinery.”

In a perfect world, a 20% increase in a sprayer’s boom width, for instance, would translate into a 20% increase in productivity. But in reality, Kastens notes, most farmers achieve significantly less than that, due to tank refill-time, irregularly shaped fields, road-travel time and other factors.

“Just because you increase a machine’s width by 20% doesn’t mean you’ll actually increase your throughput by 20%,” he says.

“With larger equipment, you’re spending more time continually making a transition; it’s a scale thing,” adds Dennis Buckmaster, a professor of agriculture and biological engineering at Purdue Univ. since 2006. Buckmaster also comes from a family of long-time farmers.

Moreover, Kastens points out, because many larger machines require more steel per foot of width, they’re more expensive, yet the same in-the-field inefficiencies still apply. As such, the investment cost on a per-foot-of-width basis is higher and the payback period is longer, he says.

“A 24-row planter can cost about twice as much as a 12-row planter,” Kastens explains. “Sometimes the labor savings will outweigh the loss of efficiency. But we’re at a point where we need to think carefully about those efficiencies. A guy operating a lot of small fields will do better with smaller equipment, whether it’s planters, combines — anything. Ever since the 1930s, we’ve been so driven by labor savings that we’ve overlooked some of the other things that come into play.”

Adds Buckmaster, “Structurally speaking, scaling a planter from 16 rows to 32 or 48 rows wide, it not only gets wider, but there’s a significant jump in the complexity of the machine because it needs heavier duty components and means for roading — everything must be beefed up. But in terms of efficiency gains and return on investment, there is a law of diminishing returns.”

In other instances, ancillary equipment hasn’t matched size increases in machinery, Buckmaster points out. For example, as manufacturers continue developing combines with more horsepower, larger heads and bigger hoppers, the size of the grain carts into which grain is unloaded has not kept pace, resulting in a “logistical mismatch.” Whether farming operations involve taking things away (like crops during harvest) or supplying and servicing (planting, spraying and spreading), often it is the logistical systems that offer room for machinery system-capacity improvements, he notes. Soil compaction poses another challenge when using larger equipment, Kastens points out.

So what lies ahead for productivity improvements? Both experts say it’s possible to increase the speed of some operations, as well as achieve more productivity through robots and “leader-follower” technology. Let’s break it down by category: