Agriculture is among the largest sources of climate-warming emissions in the U.S. Though tractors are a small culprit, experts believe an environmentally friendly machine would still attract buyers interested in sustainability.

At an August event, researchers at Michigan State University asked farmers what they think of a new electric tractor. The market is so new they’re still trying to figure out if they’ve designed it well enough to excite growers of specialty crops like carrots, asparagus and blueberries.

The small, battery-powered machine isn’t meant to replace the giant diesel tractors used on big commercial soy or corn operations. Powerful enough technology for that could be decades away.

Researchers say they think electric tractors could be game-changing for smallholder farmers who grow a large majority of food around the world, and for growers who care about being more sustainable and want to market their crops as such. 

As farmers at the demonstration took turns climbing in — some surprised by its quick acceleration — they gave real-time feedback to the Michigan State University researchers who have been developing it for over two years. The farmers remarked on the motor's quiet whir. Most were intrigued, or at least open to the idea. Some were concerned that the battery on the underside of the carriage would mean a lower clearance over the field, while others worried that it would simply be too expensive.

There are downsides — electric tractors are aimed at filling a niche, not overturning the status quo. And while battery technology has come a long way, they can’t last all day or match the massive horsepower of a diesel engine that sets giant tractors cruising through the sprawling grain and soybean operations of the Midwest.

Ajit Srivastava, an agricultural engineer and Michigan State professor who hosted the farmer feedback session, wants to help smallholder farmers across the world. Such farmers grow about a third of the world’s food but many do it with only hand tools. He started trying to emulate a pair of oxen made of off-the-shelf parts, so anyone could build it themselves.

It's still a work in progress. Rain postponed last month's original feedback session because the tractor hasn't been waterproofed yet. It also doesn't have enough power for some jobs like hauling lumber or tilling, and its turning radius in self-driving mode is too wide. But farmers generally like what Srivastava had developed. He hopes it could eventually be sold for roughly $30,000, substantially cheaper than some of the competition.

Some entrepreneurs see electric tractors as a step on the path to automation — fewer workers, more efficiency and less cost. Engineers are now designing machines that will drive themselves and power precise weeders and planters.

Srivastava also said he's just trying to make people's lives easier — looking backwards all day to make sure a plow is operating properly is grueling. A self-driving tractor would let farmers pay more attention to ensuring harvesting is happening properly, or the weeder isn't accidentally digging up crops.

(AP Video by Joshua A. Bickel)