Captain Kirk of Star Trek movie fame would feel right at home operating the controls of Planet Earth’s largest agricultural robot, currently operating in an energy sorghum varietal trial in Maricopa, Ariz.

The crop analytic robot, similar in appearance to a gantry crane, features a Volkswagen-sized field scanner loaded with the latest precision agriculture tools to precisely measure crop growth with unprecedented resolution.

The field scanner which moves east-to-west, north-to-south, and up-and-down above the field is located at the University of Arizona’s (UA) Maricopa Agricultural Center (MAC).

Over time, plant data collected by the field scanner will be shared with commercial and university crop breeders to help speed up the natural breeding process in energy sorghum varieties to boost yields and biomass content. The same tools could one day by use to collect plant data for breeding other types of crops.

Over the long term, improved energy sorghum varieties can help growers increase biofuel production, thus helping reduce this nation’s dependence on foreign oil.

Robot ribbon cutting

At a June ribbon-cutting ceremony for the robot field scanner system, DOE Advanced Research Projects Agency-Energy (ARPA-E) Director Joe Cornelius described the project as “agriculture’s version of the Hubble” (telescope), saying the project’s faster breeding results could place improved varieties in growers’ hands sooner.

The DOE’s Ellen Williams said the project would “revolutionize plant breeding.” She believes the sorghum project could accelerate the plant breeding process by two to three fold.

Shane Burgess, UA Dean of the College of Agriculture and Natural Resources, noted, “This is history in the making.”

Led by the Donald Danforth Plant Science Center in St. Louis, Mo., the field scanner robot project includes specialists from several universities, the federal government, and the private sector.

In the first year of the four-year project, the sorghum trial is largely funded by the U.S. Department of Energy (DOE). The project budget is about $8 million, not including the field scanner.

The UA receives about $1.6 million to cover the costs to construct the site and for its day-to-day operation.

Studying grain crops - vegetables?

A panel of durum wheat was planted in February to test the system. The sorghum was planted in sorghum in mid-April and harvested in mid-July. A second sorghum crop will be sown in August for additional scanning. Durum wheat will be planted this next winter – all using the same field scanner system.

Other crops which could be studied in the future include iceberg lettuce which could benefit produce farmers in the longer term in California, Arizona, and other vegetable-growing regions.   

Water Updates

Providing day-to-day onsite guidance on scanning strategies and manual sampling is plant physiologist Jeff White of the USDA Agricultural Research Service, based at the agency’s Arid Lands Agricultural Research Center located on the MAC farm.

‘Boots on the ground’ UA staff include agricultural engineer Pedro Andrade (based at the MAC), agronomist Mike Ottman, plant scientist Maria Newcomb, and electrical engineer John Heun.

Andrade’s initial fingerprint on the project was building the site which includes concrete pilings buried nine feet underground, and choosing which precision agriculture tools to utilize.

Robotic tool bag

He says, “This project relies heavily on imaging to capture plant information. The scanner includes hyperspectral, thermal and fluorescence cameras, RGB cameras to create 3D plant models, and lasers.”

For example, the fluorescence cameras shoot a burst of extremely bright light on the plants and then monitor the fluorescence coming off of the plants. This reveals the photosynthetic capacity of individual leaves.

With the compilation of these technologies, White says, “We can view a plant down to about a one millimeter pixel size. It’s meant to be a Rosetta stone for designing future plant phenotyping systems.”

Growers familiar with ‘normalized difference vegetation index’ (NDVI for short) understand that NDVI uses two wavelengths to measure crop status, including heat stress. Images captured by the field scanner can combine 1,000 wavelengths, creating once imaginable photos which explain in unprecedented precision how crops grow.

Accelerated plant breeding 

“This project can advance plant breeding and genetics to a whole new level,” White says. “Breeding is a numbers game. It’s about breeders more efficiently managing crosses and selections to quickly select the best plants.”

Andrade says the field scanner can be operated 24 hours a day. Monitoring plant growth at night could reveal plant growth patterns never observed before by scientists.

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The size of the sorghum field is 656 feet in length and 82 feet wide. The sorghum plot, planted in mid-April, includes a large number of varieties, including cultivars and research lines developed by sorghum plant breeders Bill Rooney of Texas A&M University and Steve Kresovich at Clemson University.

The field was irrigated up with sprinklers, followed by above-ground drip irrigation provided at no charge by Netafim USA. Plant rows are 30 inches wide, wider than current commercial plantings elsewhere to better study individual plants for a longer period of time.

The water source is groundwater. The soil type is sandy Trix, a mixture of 70 percent sand, 12 percent silt, and 18 percent clay.

The sorghum planting includes sweet, forage, and energy sorghum varieties.

Why energy sorghum?

Energy sorghum grown for biomass for energy is not a major crop currently grown in the U.S. Yet this sorghum type could be planted on smaller acreage parcels in the Southeast due to the region’s higher rainfall, the crop’s economic potential, and with less likelihood of the fuel crop acreage displacing major food crops.

Why was the robot system built in Arizona? Arizona has sunny skies about 11 months of the year without heavy rainfall commonly found in other regions of the country.

Andrade says, “This is a very expensive research tool so you want it to work in a relatively cloud-free environment. Major rainstorms are rare in this arid, low desert environment so this location maximizes year round use.”