Off the Record: Remote sensing technology is humming along slowly

In November 1994, I had the opportunity to travel with Jim Watson, Ph.D., Toro Company, to the John C. Stennis Space Center. Stennis Space Center is a NASA rocket testing facility on the Mississippi-Louisiana border.

We were there to visit the Space Remote Sensing Center. They combined aerial photography with global positioning (GPS) and geographic information systems (GIS). Remember, this was before you could use your smartphone map for driving instructions.

A year later, I wrote a story for the October 1995 issue of Grounds Maintenance. The subhead for the story was, “The future holds great promise for golf-turf management. Using new remote-sensing technologies and software, golf courses have a greater potential for pinpointing problems.” 

The future promise has come about very slowly.

Scouting possibilities

One potential use was to identify a problem before seeing it with our own eyes. Infrared and multispectral sensors are camera tools that show plant health. However, the camera system back then was large and fit in the belly of a small airplane. Drone or unmanned aerial vehicles (UAV) were several years down the road.

For example, near-infrared reflectance (NIR) provides a normalized difference vegetation index (NDVI). Using a ratio of the spectral data depicts healthy areas in green, while yellow, red or brown are under stress.

By this time, a startup company, Links Diagnostics, Inc. (LDI), was mapping Congressional Country Club, Bethesda, Md. LDI wanted a course near Washington, D.C., and the venue would host the 1997 U.S. Open. The WHoleView image from an LDI flyover showed colorful differences in turfgrass health.

The technology was pretty exciting, but nobody knew the cause of turf stress depicted on the maps. The USGA started to support research to provide ground truth for the NDVI images. Researchers showed NDVI has a positive relationship with tissue nitrogen, shoot density, green coverage and above-ground biomass.

Mounted systems

Several university agricultural engineering teams were developing imaging systems mounted on tractors. The group at Oklahoma State University developed the Greenseeker to provide NDVI estimates. Toro Precision Sense uses the Greenseeker to determine turfgrass stress relative to soil moisture.

In 2006, UAVs for non-military ventures expanded quickly. The same year the Federal Aviation Administration issued its first commercial drone permit. Several affordable hobby drones entered the scene a few years later. Many had a GoPro or similar camera mounted to the bottom.

Turfgrass researchers mounted sensors to produce NDVI images of turf drought stress. Breeders used UAVs to evaluate thousands of individual plants in nurseries.

Work at Virginia Tech University mapped spring dead spot outbreaks on golf fairways. The goal is to know where to spray preventative fungicides in the fall before the disease does its damage. The researchers also are starting to map early dollar spot outbreaks.

Taking flight

At the GCSAA Conference and Trade Show, several companies had various UAV services. One large UAV could apply a pesticide to a specific area mapped on the course. Still, one of the more popular UAV services is traditional aerial photos or video.

Regardless of your thoughts about UAV technology, there is potential. A successful UAV service must provide daily information documenting turfgrass stress. It would be cool to see how the golf course changes daily over a week, like rainfall radar maps. Then it would be up to the superintendent to interpret what is causing the changes.

Mounting sensors on drones or mowers to provide a different course view is exciting. In the long term, this technology help scout the course for pest problems and plan IPM strategies. Targeting soil nutrient or moisture samples will help manage fertilizer and water better. It is just humming along slowly.