Part III: Let’s Go Sight Turf!
Pop those new sight turfing sunglasses on and let’s go look at some turfgrass! As you train your turf eyes, you’ll want to look at the grass from as many different perspectives as possible. By that I mean observing at different times of day and from different sun angles. The same area on your field can look very different depending on these variables, and the added information can increase your treatment batting average.
Early morning is a great time to sight turf. Without as much sunlight reflecting off the grass, green-blue wash is diminished, and you can tease out the details. Have you ever noticed how many TV and movie productions are shot early morning or late day? They call it “movie light,” and it’s preferred for the same reasons.
Morning dew and guttation on the canopy is a good indicator of grass health and consistency of the stand. You really won’t see a healthy dew on unhealthy turfgrass. Dew can be a challenge on game day, but it can tell you a lot as a sight turfer. Later in the day, as the sun gets brighter, you’ll want to examine an area from two different aspects: sun at your back and sun in your face. This can make a big difference, and sometimes you’ll swear it’s not even the same grass. Grain from mowers can further amplify the difference in appearance from different angles. Pop your sunglasses up and down a few times to compare what you see with your naked eyes to what you see through the sunglasses.
Look macro and look micro. Observe the field as a whole, scanning across the ground close and far. I’m looking for consistency here, anything out of place. What’s my first impression? Now, get on hands and knees and take a close look at a representative area. Maybe dig or pull out a small sample with some roots and soil. Separate the sample down to a single plant or shoot. What story is it telling you? Compare older leaves to younger leaves and read the plant’s recent history. You may even want to use reading glasses for this part, especially as you get older and maybe lose some definition in your sight like me.
You’re a sports field manager, so I shouldn’t have to tell you that you can learn a lot from smelling the sample. I look for one of two things: Is the smell a healthy, earthy smell, like you get in a greenhouse; or does it smell unpleasant, more like rotten food? This may indicate that the rootzone is not providing enough oxygen for healthy turfgrass growth and development. Are the roots white and plump, or brown and withdrawn?
On a grass sports field, this is when I’ll do my “push-test.” Place one hand on the turf as if you were going to do fingertip pushups. Now, wiggle your fingers in little circles to work your way down through the canopy into the thatch/soil matrix. With strong down pressure, push your fingers down and out, trying to cut a groove into the soil about 0.5-inch deep like a cleat skate. Give it a subjective number value, 1 to 10, depending on the force required to make a skate. With practice you’ll be able to accurately predict footing on a field before the game or practice.
You should use almost all your senses when sight turfing, but I don’t recommend taste. Do you listen to the turf as you walk across it or brush your foot over the canopy? Is it loud and resilient or soft and quiet? Grab a little grass. How tough is it to pull out of the ground or pull apart? Take notice of footprints and maintenance vehicle tire marks on the turf.
How do all these things compare to the last time you were on this field? To what do you attribute any differences you’ve noticed? Look for problem spots in the sward of grass. Anything that’s not green is a potential problem.
When you notice something of concern, open a case file and do a little detective work. Compare symptomatic and asymptomatic areas on the field. Is the issue a natural occurrence or man-made? Signs and symptoms with straight lines are usually human related, and the turf team is often the culprit.
Collect samples from both the healthy and suspect areas. Compare the samples as well as the soil in the two representative spots. In my experience, the vast majority of turfgrass problems are soil related. Begin to develop a working hypothesis on the issue, and then have other turf team members try to shoot holes in the theory. Don’t get sold on anything too early. Remember, see what you are not looking for. Sometimes you have to wait a little for the story to progress before taking action and changing any treatment practices. Taking no action is often the best option. Do no harm, manage your fundamentals, and nature will often sort things out in turfgrass stands.
Sight turfing is a way of life for the sports field manager. It becomes not so much deliberate, but an ongoing process always running in the background of the sports field manager’s mind. It takes practice, patience and effort to develop good turf eyes. I tend to literally sight turf every patch of grass I encounter in my daily life. It may only be for 1 second as I drive by a park in the car. If you have ever been on a “seminar on wheels” type excursion with me, you know I tend to delay the bus to the next site. I’m not trying to be late, I just can’t not sight turf.
They may be small observations; for example, I always liked the fairway turf on a healthy course when playing golf. The turf just felt “tougher” than my sports field grass. My push tests would consistently be an 8 or above on well-drained fairway cut turf. My management program is not much different than what’s done on the golf course, and we have the same grass species, so it had to be height of cut. The intermediate cut and roughs didn’t seem to have this tough feel, just tees, fairways and greens to some extent.
As I experimented with lowering my height of cut, within reason closer to fairway height of cut, I started noticing a similar toughness on my turf. It’s simple Turf 101, really: Lowering height of cut will tend to result in a shallower root system, but more mass in the top of the rootzone where the cleats interact. A simple sight turfing observation like this can make a big difference in the quality of surface that the field manager delivers.
Don’t ever just walk past part of your field that looks “off.” Never. Stop and do a little sight turfing on it, and open or refresh the case file on the issue. Get other sight turfers to look over the issue; they often notice different things than you do. Don’t steer these colleagues to a conclusion, give them space to make an independent hypothesis. Ultimately it’s your call, and you’re the most qualified person to make it.
The future of sight turfing is bright. Researchers have long used radiometric instruments to more precisely measure and quantify the canopy reflectance of a multitude of crops, turfgrass included. Only lately have we seen some reasonably priced sensors, sometimes called chlorophyll meters. They’ll set you back a few thousand dollars for now, but prices will come down. In general, these meters measure the spectrum of light reflecting off a turfgrass canopy and compares that to the light reflected off a non-chlorophyll containing surface like bare soil. How much of the available plant-usable light is being absorbed by the turfgrass? The indices reported by these sensors have been correlated to trained visual evaluation of turfgrass quality, and more and more they’re being tied to pre-deterministic evaluations on everything from drought stress to fertilizer efficacy and release curves.
GPS technology and developing computer software can be used to generate a color-coded field map for the various parameters. Hook this unit up to the back of your mowers and you could get frequently updated maps on all sorts of turf health vital signs. A new precision turf management shift is emerging, and enhanced, computerized sight turfing and mapping will be a significant part of this future, quantifying and improving the subjective sight turfing method.
So that’s how I look at turf.
Ross Kurcab, CSFM is a certified sports field manager, consultant and owner of Championship Sports Turf Systems. He was the head turf manager for the NFL’s Denver Broncos for 30 years and holds a B.S. in landscape horticulture/turfgrass management from Colorado State University. You can reach him at firstname.lastname@example.org.