Source:  NCDA&CS 2/18/11

Matt Carver, superintendent of Brushy Mountain Golf Club, says he isn’t used to seeing many “agriculture guys” — aka crop consultants — around golf courses. After all, are golf greens really a crop?

Yes, says Steve Dillon, regional agronomist with the N.C. Department of Agriculture and Consumer Services. Last year, the department’s Agronomic Services Division laboratory analyzed at least 8,200 samples from fine turf. These included soil samples for nutrient analysis, plant tissue samples to monitor nutrient uptake, irrigation water samples for assessment of chemical properties and soil samples tested for the presence of plant-parasitic nematodes, which are microscopic roundworms.

“A golf course may not be a farm,” Dillon said, “but keeping it healthy and picture perfect requires a fair amount of science. I’ll admit that I know more about corn and soybeans than turf, but the key element is knowing about soil fertility and plant nutrition.”

As an experienced superintendent, Carver is no stranger to intensive management. Last year, however, was especially challenging, and he talked fairly often with “agriculture guys.”

“We really did experience a perfect storm,” Carver said. “We had a cold winter where the ground was frozen for a month, followed by a hot spring, then a hot, dry summer. A combination of heat, stress and low pH kept roots from growing.”

Carver remembers first seeing the evidence of serious decline on April 25. His assistant interrupted his Sunday brunch to report that a green had developed dramatic yellow patches overnight. The same area had looked healthy the previous day, showing no signs of stress.

Brushy Mountain’s greens are planted with bentgrass, which is very delicate. It is kept at a height of 1/8 inch and very carefully manicured. Small doses of fertilizer are applied at frequent intervals to ensure good growth. Since hot weather tends to cause a decline in root function, Carver’s immediate response to the problem was to favor the roots by aerifying the soil and reducing compaction.

Then he began to think the problem could be more than a temperature response. He contacted Dr. Leon Lucas of the Carolina Golf Association to help troubleshoot.

Lucas, a retired professor of plant pathology from N.C. State University, sent soil and tissue samples to NCDA&CS for nutrient analysis and clippings to the Plant Disease and Insect Clinic. He ruled out disease and herbicide injury. After identifying low soil pH as a possible factor, Lucas advised Carver to have his irrigation water checked and to look further into the need for plant nutrients. He recommended contacting a regional agronomist.

Dillon responded to Carver’s call within 24 hours and performed an on-site evaluation. He collected irrigation water samples for solution analysis and demonstrated how to collect matching sets of soil samples from “good” and “bad” areas for problem diagnosis. After this tutorial, Carver sampled the entire course, collecting soil samples to pinpoint nutrient problems as well as samples for a nematode test. Dillon made a return visit to explain sample-submission procedures.

With regard to the range of available tests, Carver said, “I wanted everything I could get. I wanted answers.”
Within a week, results were available online. The irrigation water had an acceptable pH and minimal mineral content. Populations of plant-parasitic nematodes were below threshold levels.

The soil report, however, indicated a need for fertility adjustments. Soil pH, potassium and magnesium were low, and all three contribute significantly to turf health and vigor. They are particularly critical when turf is under stress, as it was last year.

Dillon recommended an application of dolomitic lime to raise the magnesium and pH levels. “That way the two issues could be addressed at once,” he said. “And potassium- that’s one you have to stay on top of. There’s a tendency to apply less when prices are high. It’s not a good idea though, especially on golf courses, because routine irrigation washes potassium out of the root zone. Greens need regular and frequent replenishment.”

Carver believes that agronomic services have helped the golf club improve its turf maintenance. “I think the ultimate cause of poor growth was poor roots [due to] all the nutrients we were missing,” Carver said. “Being able to compare results from 'good’ and 'bad’ soil samples was very helpful.”

The department has 13 regional agronomists who can make site visits. They can provide advice on collecting and submitting agronomic samples, interpreting test results, liming, fertilization, irrigation and nematode management. To contact the agronomist assigned to your area, visit www.ncagr.gov/agronomi/rahome.htm.