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A ride in ARS' own "Air Force One".

A Ride in ARS' Own "Air Force 1"

On a bright clear morning, pilot Rene Davis is cruising at 7,800 feet about 12 miles northwest of Weslaco, Texas. Seated behind Davis in the twin-engine Aero Commander 680S is David E. Escobar, remote sensing specialist.

The Agricultural Research Service obtained the plane in 1978, after the Drug Enforcement Administration broke up a ring of drug smugglers. Today, ARS' Davis and Escobar are using the plane to snoop on sick sorghum. It's all part of research aimed at finding whether airborne video can tell farmers, ranchers, and ag consultants what they need to know - faster and cheaper.

Escobar's eyes are riveted to a video monitor on the cabin floor beside his seat. As an agricultural landscape glides across the monitor, he suddenly spots the field he's looking for.

"Hold it right there," he calls over the engine noise.

Davis reduces the power, and the aircraft, aimed into a stiff headwind, seems to hover over the field like a gull over a beach. The TV scene on the monitor enlarges; the headwind is no match for gravity, and the plane is slowly losing altitude.

On the monitor, an elongated pink blob lies diagonally across the otherwise magenta-colored crop field.

Escobar doesn't touch any dials; there's nothing wrong with his set. The magenta color represents healthy sorghum; the pink blob is caused by chlorosis, an iron deficiency that blanches the sorghum's leaves and cuts yield.

Escobar can already see that the blob takes up at least one-third of the field. But Davis' piloting aims the cameras so Escobar can get the best possible image of the blob; he and other scientists at the lab can have a computer calculate its dimensions.

The video scene is a color-infrared composite made by combining images taped simultaneously by three cameras, each with a different light filter. The cameras, bolted to a steel frame, peer down through a porthole in the cabin floor. One camera has a near-infrared filter; the second, red; the third, yellow-green. The resulting black and white images - which appear similar to the untutored eye - feed separately into three Super-VHS recorders. A fourth recorder snares the color-infrared composite. The cover photo is an example of this.

Years of studies by range scientist James E. Everitt, Escobar, and others at Weslaco's ARS Remote Sensing Research unit and elsewhere have established specific "signatures" for plant, soil, and water conditions that show up best on one or another of the three cameras and can then be interpreted in the color-infrared composite imagery.

In color-infrared, healthy vegetation typically appears as magenta. Diseased areas have dull red or brown tones - or a bright pink like the chlorotic sorghum. Bare areas, such as ant mounds or soil that is too salty or dry for crops, appear whitish-gray to white.

As the second tick, Escobar flips switches, alternating the monitor among the similar black-and-white images from the three cameras and the composite.

After 24 seconds, Escobar's seen enough. "Okay," he cues Davis, who adds power to the engines at 6,800 feet and heads the plane back to Weslaco Mid-Valley Airport.

At the Weslaco lab a few hours later, Everitt, Escobar, computer specialist Rick Villarreal, and computer aide Noel Garcia will plot the imagery on a computer. Using software called "image processing," they'll determine that chlorosis covers 41 percent of the 130-acre sorghum field. Yield from the field will be cut by 25 percent or more.

Enabling farmers to act quickly to counteract diseases and insects and to estimate probable yields are only two potential uses for this promising video technology. Already, visitors from several agricultural companies, government agencies, and growers' groups have made trips to Weslaco to see how the system works.

An Australian firm is now using the ARS scientists' basic three-camera system design to provide information for irrigation management in cotton. And it is getting high ratings from U.S. agricultural and environmental audiences interested in a faster, cheaper way to get the latest news on range, pasture, and croplands.

Everitt says farmers and ranchers may someday pop a tape into a VCR every week or so to check whether - and how fast - rice borers are spreading through sugarcane, toxic weeds are marching across the range, or sooty mold is growing on citrus leaves that have been "slimed" by leaf-sucking insects like blackflies.

Toxic waste leakeage from dumps, hail damage to crops - even mighty volcanos and tiny oysters - may someday be tracked by the kind of video system developed at Weslaco.

Everitt developed the system along with Escobar and electronics technician Juan R. Noriega. "Airborne video is ready to take off," says Everitt, "partly because the industry's recent invention of Super-VHS recorders makes for a sharper image on a screen." Super-VHS yields more than 400 lines of horizontal resolution compared with 240 lines for typical home recorders.

"But making that extra resolution useful to agriculture," he says, "has meant learning from three decades of research on interpreting aircraft and satellite data" by scientists at ARS, the National Aeronautics and Space Administration, universities, and private companies. "Aerial video won't replace aerial photography and satellite data, but it can provide a lot of information faster and cheaper."

Film for aerial photography and processing can cost $200 to $1,000 a roll; a 2-hour, reusable Super-VHS tape costs about $15. "Plus," Everitt adds, "video cameras have higher light sensitivity than film and that allows them to get better results on hazy or cloudy days.

"Since there's a video monitor right in the plane's cockpit, we can monitor the action live - we can see what we're getting while we're getting it."

Then, as with the pink blob video, Weslaco scientists can quickly convert the video images into numbers to estimate how many acres there are of - right now - about two dozen different weed, disease, crop, and soil conditions.

Recently, Everitt demonstrated the high-tech multispectral system for specialists from the Environmental Protection Agency.

"It has potential to supplement our conventional aerial photo studies," says Gordon Howard. He's based in Warrenton, Virginia, at the EPA's Environmental Photography Interpretation Center (EPIC).

Howard thinks the video system could help reveal leakage of chemicals from hazardous waste dumps. "If it spotted dead or dying trees or other plants near a dump, we'd check on the ground to see whether chemicals are responsible," he says.

According to Clay Lake, a project officer for EPIC in Las Vegas, Nevada, "Nothing else we've looked at is as good as what they've got at Weslaco. We're impressed with its high resolution. A system like that would give us a quicker, easier way of discovering illegal dumping and monitoring its effects on an area."

Lake believes color-infrared airborne videos could also help EPA see if illegal stream dredging or filling is destroying wetlands, direct emergency cleanup crews to oil and other pollutant spills, document cleanup at Superfund sites, and monitor how well vegetation recovers after a spill. "We've already bought one system like Weslaco's experimental one. We'd like to see one at each EPA regional office across the country," Lake reports.

From videos, investigators could get a faster, cheaper way to collect evidence and prepare reports for use in court, according to Steven Sisk, a groundwater hydrologist at EPA's National Enforcement Investigation Center in Denver.

"On board the plane," he says, "an investigator would narrate as a site is recorded on video. Back on the ground, we would digitize the images and quickly convert them into a map. The map would highlight important features, including overlays showing the site's geology and groundwater."

Your Check's in the Mail - Sooner

Mark Fuchs, a crop insurance specialist, says airborne video could enable companies to settle crop insurance claims faster after hailstorms or other disasters strike.

Fuchs works for National Crop Insurance Services, an industry trade group. Based in Overland Park, Kansas, NCIS works out policies and procedures used by claim adjusters of member firms.

Settling a claim for hail damage is often more complicated and time consuming than what happens after you dent your car fender, he explains.

"When you wreck your car, the damage is done. The car won't fix itself or suffer further damage," he says. "But with a crop field, you're looking at living organisms and it's often hard to know how well the plants will recover."

An adjuster might still be walking a field after dark - and after a big hailstorm there may be hundreds of farmers in line.

About 5 years ago, NCIS ran a pilot program using infrared aerial photography. Results were good, but the time lag from flight to photo was usually more than a week. And the photos all required visual interpretation. With digitized imagery, a computer could interpret conditions.

"Since a photo is a chemical emulsion, you need an extra step - computer scanning - to put the data on computer. Video is already electronic," he notes. "Not only does it give us visual and computer data much faster - perhaps the same day - but also the adjuster can quickly and accurately determine location and size of damaged areas.

"We still have a way to go before we can use the new technology. But a company with dependable video imagery and interpretation would have a great selling point. The farmer would get a faster response and a loss estimate based on information that he or she can literally see."

Orbiting Video?

Weslaco's airborne video may someday soar into space, according to Victor Whitehead of NASA.

"We would like to work with ARS to develop a multispectral video system mounted in the payload bay of the shuttle," he says. "Something like it could also go aboard the space station when that's built."

Among the possible uses is monitoring marine environments such as Texas' South Padre Island. There, unique oyster beds are threatened by water pollution from rapid urban development.

"With a multispectral video, we could also capture events like major floods and volcanic eruptions in real time," says Whitehead, a meteorologist in the Flight Science Support Office of NASA's Lyndon B. Johnson Space Center in Houston. "Our main job is helping astronauts to document their missions and to get useful imagery for a range of scientists studying natural resources and the environment."

Shuttle astronauts already use conventional video to monitor activity in the playload bay, he says. They also take photos of Earth with cameras mounted in the bay.

According to Whitehead, "multispectral video would give unlimited coverage time, and the imagery could be instantly telemetered to Earth. With film, we have to wait until the spacecraft returns."

Everitt, other ARS scientists, and NASA recently began a different study to interpret photographs taken last October by the crew of the Columbia shuttle. The pictures include the South Padre oyster beds.

The Weslaco site is ideal for cooperative studies with ARS, Whitehead notes. "The shuttle frequently flies over that area, where ARS can get ground information used to check interpretations of video or photo imagery." The U.S. space station is slated to orbit over the same latitude, he adds.

Meanwhile, Back on Earth...

Everitt says tests of the video system are being planned with the Rio Grande Valley Sugar Producers Association, which is concerned about outbreaks of rice borers. "It's pretty hard to see anything from the ground in a big sugarcane field once the crop gets high, but we can spot borer damage from the air," he says.

By accident, the scientists recently discovered that the system can also spot a disease in another tall plant, kenaf, which grows to about 15 feet high.

Charles Cook, research geneticist at Weslaco, has some test plots of this experimental crop, which may someday become a significant source of pulp for paper and high-protein forage for cattle.

During a flight over the research plots last summer, Escobar noticed on the video monitor a dark stain that proved to be root rot. Cook hadn't known about it because the plants were too tall for the evidence to be seen from the ground.

Everitt's team often supplies video for ARS projects. For example, the team recorded video transects, slices of coverage several miles long and about 100 years wide, of the agency's 197,000-acre Jornada Experimental Range in New Mexico. Scientists use the transects to study how the number and kind of range plants are influenced by escarpments - long, low natural ridges that trap rainwater in the dry climate.

Airborne video could also help map the spread of saltcedar, a shrubby tree that can, according to Jack DeLoach, "block a stream or channel and make it disappear. And it damages wildlife habitat by displacing native plants most game and songbirds prefer." Jack DeLoach is at the ARS Grassland, Soil, and Water Research Laboratory in Temple, Texas.

Imported as an ornamental in 1837, saltcedar clogs thousands of miles of western streams. "It has almost taken over the Pecos and Brazos Rivers in west Texas, Rio Grande in central New Mexico, Gila and Salt in Arizona, and Lower Colorado between California and Arizona. It's gone north as far as Montana," DeLoach says. Besides robbing the dry land of precious water - 3 to 5 feet per year - thickets of this Middle Eastern native make a stream channel less able to carry storm flows. The channel collects sediment, making floods more frequent and widespread.

"But with video," he notes, "we have a tool that makes it feasible to find out how much saltcedar we have and how important and effective a solution might be. In late fall, saltcedar leaves turn a unique golden-orange color that makes the plant - even individual trees - easy to spot from the air. The images can be turned into computer data showing the area covered by saltcedar."

Chemical or mechanical control is difficult and time consuming. DeLoach, an entomologist, wants to find, import, test, and release the tree's natural enemies - insects or microorganisms. Airborne video could help monitor the effectiveness of biological controls for saltcedar and other pests, he says.

Everitt says research has laid at least some of the groundwork for other potential applications of airborne video, including:

* Range and pasture forage growth, so stocking rates for grazing animals can be adjusted.

* Changes in the makeup of range plant species in response to weather and grazing practices.

* Damage from herbicide drift.

* Nutrient deficiencies in alfalfa, corn, cotton, and other crop and range plants.

* Overall crop vigor and production both in this country and less developed ones having few or no facilities for processing aerial photo film.

"The hardest part," he says, "is knowing how a plant or a pest or whatever gives itself away to the camera." Once research establishes these facts of light, modern video and computer technologies take over. - By Jim De Quattro, ARS.

James H. Everitt, Charles Cook, David E. Escobar, Noel Garcia, Rick Villarreal, Juan R. Noriega, and Rene Davis are in the USDA-ARS Subtropical Agricultural Research Laboratory, 2413 E. Highway 83, Weslaco, TX 78596 (512) 968-5533. Jack DeLoach is at the USDA-ARS Grassland, Soil, and Water Research Laboratory, 808 East Blackland Rd., Temple, TX 76502 (817) 770-6520. To reach others mentioned in this article, contact Jim De Quattro, Room 336, Bldg. 005, BARC-West, Beltsville, MD 20705 (301) 344-3648.

On Camera, Researchers Capture The Beast - All 924 Acres of It

Some of the peskiest creatures on Punta del Monte Ranch are wild pigs that compete with cattle for the range forage. But because they're popular game among hunters and favored at barbecues, the wild pigs are considered a net plus.

That can't be said about a different ranch-devouring critter: false broomweed, nicknamed The Beast.

Last summer, The Beast became the quarry in the toughest trials yet of ARS airborne video. The research mission: Map the territory taken over by the weed at the ranch, an 11,000-acre spread north of Raymondville in south Texas.

"I guess the best thing about this weed is, it only grows a couple of feet tall. But where it grows, nothing else will," says Dan Butler, who operates Punta del Monte with his brother Richard.

Cattle won't eat false broomweed; it quickly pushes out native forage plants, and it resprouts readily despite chemicals, burning, and a variety of mechanical measures.

"Actually," says Dan Butler, "a lot of things work on it - until the next year, when it just comes back."

"For the Butlers, the news from last summer's study has not been good, but we're confident it's accurate," says James Everitt, who heads ARS Remote Sensing Research. "We found that the weed covers 8.4 percent - 924 acres - of the ranch. Ground mapping of the entire ranch gave a close correlation - 7 percent."

Nine hundred acres of grazable forage can support 40 to 90 cattle.

The brothers' ranch is the only one in the United States that's the subject of a complete, computerized multispectral video map, Everitt says.

First, researchers had to decipher the weed's video signature - its unique light-reflecting properties. They determined that the near-infrared filter would get the best video fix on the weed.

After mapping the ranch at about 10,000 feet, they used image-processing software to create a digital mosaic. Any scene on the mosaic can be accessed by punching its coordinates into the computer - the process is somewhat like using grid points to find a city on a road map.

Everitt says the findings could help the Butlers direct aerial applicators who put down weed-killing chemicals. Future video coverage, he adds, could tell the rate of control - or further spread - of the weed.

The Butlers - cooperators with ARS and Texas A&M researchers for many years - would like to try using the weed's natural enemies. But no such suitable insect or pathogen has yet been identified.

"I feel bad that the new information, while it's vital to testing the technique, probably isn't going to help the Butlers and other ranchers much, right away," says Everitt.

"But by letting us fly over, walk over, and drive through their land, they're helping us carry out research that may lead to a workable solution." - By Jim De Quattro, ARS.

PHOTO : Remote sensing specialist David Escobar checks infrared video scan of cropland thousands of feet below. (K-3931-16)

PHOTO : James Everitt and David Escobar study images of grain sorghum suffering from leaf chlorosis. (K-3931-5)

PHOTO : From 4,000 feet above, healthy sugarcane appears solid red in field at upper left. Lighter areas within the red indicate rice borer damage and soil salinity problems. (K-3957-1)

PHOTO : Harvester ant beds dot this infrared video photo of a cottonfield. Harvester ants destroy vegetation within an 8 to 10 foot circle, making the low mounds readily visible from 7,300 feet altitude. (K-3957-11)

PHOTO : Dark areas are brushy plants; light areas represent grass. Dry lake beds appear circular. (K-3959-11)

PHOTO : David Escobar, Punta del Monte Ranch foreman Espidio Salinas, and James Everitt examine a false broomweed plant. (K-3932-17)
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Title Annotation:Agricultural Research Service remote sensing plane uses infrared video to observe vegetation
Author:De Quattro, Jim
Publication:Agricultural Research
Date:Feb 1, 1991
Words:3140
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