By Carol Lea Spence

Mark Williams and Joe Dvorak with the solar array that offsets all the energy used on the UK organic farm.

Agriculture has always been about innovation. Long before the ancient Greeks decided the four natural elements were earth, air, fire, and water, people were harnessing all four in an effort to create ecosystems that would sustain them. From the Chinese in the first century B.C.E. who devised a way to irrigate higher elevations by raising water with a chain pump to the Arab world developing a three-field system of crop rotation in the Middle Ages to the 20th-century development of synthetic fertilizers, pesticides, and gene manipulation, the goal has always been to increase production and make the work more efficient.

Nothing is different in the 21st century. Still, we innovate. Still, we seek to control earth, air, fire, and water. Drones are taking to the air. The sun is powering pumps and greenhouses. Tractors are starting to drive themselves. And CAFE researchers have a hand in it all.

Fire and Water

The solar array is perched on a ridgetop at the UK Horticulture Research Farm for a reason.
“We wanted it to be a statement,” said Mark Williams, interim chair of the Department of Horticulture. “We wanted people to think about sustainability when they saw these panels. And it’s working. People ask about this all the time.”

The 10-kilowatt array transforms the sun’s fire into electricity, which is fed into the power grid and offsets all the energy usage on the 30-acre organic section of the farm. Over the course of a year, the panels generate as much, and sometimes more, electricity than the unit actually uses.
The focus on the organic unit has always been on sustainable production methods. The farm's buildings, constructed from salvaged materials, were designed in keeping with that green goal. Examining ways to use solar power makes sense in that context. The project is the first phase in the college's efforts to use renewable energy on its farms.

“The success of this project has spurred on a change in the college. We’re going to take this concept to the entire farm, and we hope this will become a model that will work for other farms as well,” Williams said.

The solar idea actually began as part of another project. Joe Dvorak, assistant professor in Biosystems and Agricultural Engineering, had built a self-driving tractor with electric propulsion that they were testing on the organic farm. Dvorak and Williams applied for and received a UK sustainability challenge grant for the purchase and installation of solar panels to offset the energy usage for the tractor. Dvorak and fellow BAE professor Don Colliver designed the solar array and farm crews and technicians from the Agricultural Machinery Research Lab installed it.

“I was hoping that when we were done (with the tractor project) we’d have something permanent. You really want something that’s sustainable that’s going to have a long term impact,” Dvorak said.

Brent Rowell’s replica of John Ericsson’s sun motor   Brent Rowell adjusts a replica he built of John Ericsson’s 1873 solar-driven motor.

New, Not New

In the first century B.C.E., Hero of Alexandria invented a sun-powered siphon. In the 1860s, a Frenchman, Augustine Mouchot, grew alarmed over the Industrial Revolution’s thirst for coal. He suggested that industry “reap the rays of the sun,” and then went on to do just that by building a steam engine powered by the sun’s heat.

Horticulture professor Brent Rowell is fascinated by solar power’s long history, particularly by the work of John Ericsson, a Swedish immigrant who did prodigious work in building prototypes for solar machines in the 19th century. A video of a reproduction 1873 Ericsson machine that Rowell built is on exhibit in the Science Museum in London, England. While Ericsson used a parabolic dish to capture and focus the heat of the sun, current solar systems, like the one at the organic farm, transform the sun’s light into energy. This is the method Rowell uses for a low-pressure irrigation system he perfected in Asia. He collaborated with engineers from Ball Aerospace in 2014 to test a combination of one-horsepower solar pumps with ultra-low pressure drip irrigation in the state of Gujarat in India. They used the pumps to raise water from open wells to small tanks located about 5 feet above the field, at which point, gravity took over to irrigate an acre of vegetables.

“After we set up one system, the Indians set up nine more,” Rowell said. “They worked extremely well.”

Though the solar pumps are often too expensive for the average farmer in the developing world, Rowell is optimistic this will change, as prices drop and less expensive pumps are being developed and tested. Farmers in Kentucky with no easily accessible electricity or water to their fields or those who just want to reduce their water bill could find this system useful.

Air and Earth


The drone bucked in the stiff March crosswind, but on the ground, Joshua Jackson fought it back to the right heading over an alfalfa field on Spindletop Farm. It was a test flight for one of two different drone projects Jackson, assistant extension professor in BAE, and Dvorak are working on, studies that could ultimately make farming more efficient for alfalfa growers and livestock producers.

Alfalfa’s stem height is a fairly good indicator of nutrient value. As the plant gets taller, it puts more lignin into the stem, decreasing its digestibility. Height also indicates yield. Flying a drone loaded with a camera for hyperspectral imaging, which collects information from the entire electromagnetic spectrum, and lidar, which uses a laser to measure distance, the researchers are hoping to successfully map yield and nutritive value of a growing crop.

“We can tell both of those from the air with a UAV (unmanned aerial vehicle), so we're looking at whether we can take this information and use a UAV to map it,” Dvorak explained.

During the first season of the project, the team marked off small plots in cubic meters and flew the drone, with a standard camera that time, over the plots. Students harvested the plots by hand and then went back to the lab where they measured the quantity and quality of the alfalfa. Comparing that information to the data from the UAV, they could see what matched and could figure out the best way to process the data.

Brent Rowell advised the installation of rainwater catchment and solar + gravity-fed drip irrigation systems for high tunnels at GreenHouse 17 in Lexington.

“We have some pretty good descriptors now, so this year we’re going to start scanning whole fields with some small plots in them as a check to see if we’ve measured it right when we create a field-wise estimate,” Dvorak said.

Mapping a field by air like this should give farmers a tool to monitor the crop in almost real time in order to make better harvest timing decisions.

“We have this information, we can see what areas of the field may need more attention, more fertilizer or pest control. So really, it’s all about making management decisions,” said Jackson, who farms in Mercer County when he isn’t busy with his UK work.

The second drone project concerns livestock management, which Jackson said “is very near and dear to my heart, because I have Angus cattle. At some point I really wanted an easier and quicker way to cover a lot of ground.”

Jackson is hoping that by developing a facial recognition imaging system for cattle, he can help producers stay better abreast on how their herds are doing.

The base goal is to be able to fly the field and count the animals to see if any of them are off by themselves. The next goal is to find out why they might be separate from the others. This will involve being able to identify the animal through facial recognition. By using multiple drones, Jackson gathers an array of different images to see if they can distinguish between facial and body characteristics. They have been honing the process by sending drones around a bovine replica at different heights and different radii.

Keeping the animals stress-free is important. "We want this to be a tool to monitor them, not to stress them," Jackson said.

The work the team has done so far with actual dairy cows—measuring their physiological and behavioral changes with heartrate monitors and GPS— shows that the animals don’t seem to be bothered by the UAVs.

“Right now there are still a lot of FAA restrictions for completely autonomous flight, but we want it to be something where you can sit at your computer and instruct it to fly and tell you what the problems are,” Jackson said. “It will take a number of years to get there, and I’m hoping we’ll get as close as we can with this cattle project, but it’s something I want for beef producers. I want this technology.”

Autonomous Tractors

The small, electric-powered tractor Dvorak built and tested at the organic unit showed that something like this could conceivably work for the small- to mid-size grower. Being driverless, however, does not mean being farmerless, Dvorak emphasized.

“If you’re making decisions on what you’re planting, when you’re planting it, how you are going to manage it, the cab of a tractor is a really nice spot to be to make those decisions,” he said.
Rather than ousting the farmer from the cab, Dvorak sees a “mother-ship” arrangement with the farmer driving the main tractor and autonomous tractors spanning the field copying the main vehicle's every move. To Dvorak, the autonomy question becomes, how does it interface with the producer?

“You’re not going to get rid of the producer, because he knows what works best on that farm. But if we can make autonomous vehicles support his decision-making, that’s a whole other ballgame.”

The Long View

Ag in the 21st century has to have a long view. Agricultural methods must change in order to feed 9 billion people in the near future, while making sure to sustain the soil and find alternative fuels to ensure food production in the distant future.

What does 21st century agriculture look like to these researchers?

“We’re not trying to get rid of the farmer. Why would we want to?” Dvorak said. “But if we can support them and give them the tools to do it even better, that’s our goal.”

Jackson hopes they can make producers’ lives a lot easier.

“I see our work as complementary,” he said. “It may be idealistic, but I think that’s the way we should design it to work.”