Certifying Florida Sod: An Inspector’s Day

Clippings | Fall 2017  – View the full issue HERE:

Certifying Florida Sod:  A Day in the Life of an Inspector

Dr. Phil Busey, Phil Busey Agronomy Consulting

Since May, 2017, I have worked under contract for the Southern SeedCertification Association (SSCA) to inspect turfgrass fields in Florida sod farms. In the 1990s the SSCA, a non-profit association hosted by Auburn University, started certifying Florida turfgrass fields including sod and sprig fields. Producers apply voluntarily if they wish to be a part of the program, they pay a fee, and they follow written standards of which inspection is a part. Most certified acreage is planted to bermudagrass cultivars (varieties). Other “fine turf” species certified by the SSCA in Florida are zoysiagrass and seashore paspalum. In 2017 there were about 2100 acres of turfgrass under certification in Florida.

Inspection is one part of established standards by the SSCA to maintain and make available to the public high-quality varieties with genetic purity and identity. The genetic identity, which is part of inspection, is based on published characteristics written by the originating plant breeders and their organizations for a particular turfgrass. Standards of the SSCA cover important steps to maintain high quality varieties such as a documented chain of custody from Breeder’s Turf, to Foundation Turf, to Registered Turf, and to Certified Turf which is sold to the public. There are required pre-planting inspections. More information about the application and standards is published on the SSCA web site: http://www.ag.uburn.edu/auxiliary/ssca/

The method of production and the growth characteristics of warm-season turfgrasses provide special challenges in achieving Certified Turf. Warm-season turfgrasses are mostly propagated vegetatively as homogeneous clones and SSCA has specific standards for vegetatively propagated turfgrass. After harvest, turfgrass production fields regrow in place from ribbons or rhizomes. Due to rapid growth rate in Florida, there may be multiple harvests per year. Users of fine turfgrasses typically install sod in high visibility and high performance facilities such as golf courses and sports turf fields. The genetic consistency of vegetative cultivars is important because it provides relatively consistent, predictable response to environmental and playing conditions. Many users of fine turf demand sod to be certified, to more closely match their performance expectations. The nature of growth of warm-season turfgrass, particularly bermudagrass, causes enormous potential for off-types.

My job for the SSCA is to visit each of over 150 fields in 31 farm locations, three times per year, and visually inspect for genetic identity and if there are any other varieties, off-types, or noxious weeds. The maximum permitted off-types in Certified Turf fields is 1 per acre, defined as no more than 2 feet in diameter. If off-types or noxious weeds are observed, they are flagged for spot treatment, noted by GPS coordinates, and off-types must be removed. The tolerance for off-types in Registered Turf, fields that are expanded to plant certified fields, is zero. The tolerance in sod is zero.

Off-types of bermudagrass often exhibit a slightly different hue and shade of green. This is sometimes due to slightly different leaf colors and is sometimes due to contrasting habits of growth. For example, a bermudagrass off-type with a taller and more erect leaf habit emits more transmitted sunlight (in contrast to reflected sunlight) so the color appears more yellowish-green. In contrast, a common bermudagrass off-type looks more bluish and gray, in part because the leaf angle is more horizontal and most of the emitted sunlight is reflected, not transmitted. Consequently, off-types may be difficult or impossible discern when looking vertically down at them, but are readily apparent when viewed at a slight distance and angle. Bermudagrass off-types can best be observed under moderate growing conditions and canopy, that is, neither recently mowed nor tall or unmown.

To attempt to view every square foot of turfgrass, I observe from a distance about 30-40 feet away. This requires me to travel back and forth across fields in multiple passes about 60-80 feet apart. The ideal lighting condition for observing is cloudless and with low sun angle, early to mid-morning or late afternoon. Even at moderate travel speed, 15 miles per hour in my four-wheeler, when I see an off-type it is usually very apparent and I stop immediately. Occasionally I have to circle back and revisit spots that are questionable. I try to be thorough and precise so that almost every questionable spot is assigned, either to contextual environmental factors, such as elevation, equipment effect, or soil variation, which can be ignored, or to genetic variation (off-types) which must be removed. Off-types have defined margins not associated with environmental factors, but may exist infiltrated into the intended cultivar.

Over 40 years, I have observed fine turf plantings in golf course greens, fairways and sports fields with off-types, generally bermudagrass off-types. There are multiple possible sources for off-type bermudagrass, and it is difficult to know the source of infection, so it should be managed at different levels. In a research paper that I published in Agronomy Journal, I showed that the high compound growth rate of bermudagrass could allow one square meter of bermudagrass to take over 50% of the land area of planet Earth in 1 year. Although this was a theoretical prediction, the potential for