New optical sensing device recently introduced measures the reflectance from turf canopies to determine turfgrass growth, wear tolerance, herbicide tolerance, and fertility.

New technology measures turfgrass quality

It seems every day brings with it an announcement regarding innovative technology that will improve productivity and save time. That appears to be the case with a new optical sensing device recently introduced to measure the reflectance from turf canopies to determine turfgrass growth, wear tolerance, herbicide tolerance, and fertility.

A new study published in Hort-Technology assessed a handheld optical sensor (GreenSeeker) for evaluating overall turfgrass quality in three turf species over two growing seasons. The research team of Gregory E. Bell, Dennis L. Martin, Kyungjoon Koh, and Holly R. Han from Oklahoma State University compared the combined time required for visual evaluation and data entry with the time required for the same functions using the handheld optical sensor.

The study was conducted at the Oklahoma State University Turfgrass Research Center in


Visual quality ratings and sensor ratings were collected on schedules prescribed by the

National Turfgrass Evaluation Program and included:

• 2002 bermudagrass (Cynodon spp.)

• 2002 buffalograss (Buchloe dactyloides),

• 2002 zoysiagrass (Zoysia spp.) studies in 2003 and 2004.

The device incorporated a sensor head mounted to a telescoping pole, a compact PDA

(Personal Digital Assistance), a control box, an adjustable shoulder strap, a rechargeable battery and the unit weighed approximately 11 pounds.

The researchers concluded that use of the sensor reduced the time required to complete data collection and data entry by 58% compared with human visual evaluation.

The device was relatively inexpensive and the handheld sensor was very stable and did not require routine maintenance, update, and recalibration. It provided a consistent, objective evaluation of overall turfgrass quality”, stated Bell.

Training personnel to use the sensor, including data entry, took less than one hour; training a visual evaluator to conduct the same subjective evaluation can require several days, and evaluators can take months to become proficient.

The researchers added that although the sensor has distinct advantages, there are still reasons to include the human element in turfgrass assessment. Bell noted that “the handheld optical sensor alone cannot provide necessary information about turfgrass texture or density that can be effectively determined by human evaluators. However, it does provide a consistent measure of reflectance that is primarily affected by a combination of turfgrass color and percent live cover.”

The complete study and abstract are available on the ASHS Hort-Technology electronic journal