Turf is the talk of the town

Nutrients were the hot topic at GCSAA’s Turfgrass Talk Show hosted by Thomas A. Nikolai, Ph.D., of Michigan State University. Nikolai’s guests included Roch Gaussoin, Ph.D., of the University of Nebraska--Lincoln; Larry Stowell, Ph.D., of PACE Turf; and special guest Dave Kopec, Ph.D., University of Arizona, who gave a talk on nutrients in the desert Southwest and briefly joined the house band, Henry and the Latin Beats. 

Gaussoin addressed the knowns and unknowns of nutrient uptake. Once the nutrient is in the plant, said Gaussoin, it doesn’t matter how it got there --- whether the application was granular or foliar. Turf leaves readily take up nutrients in soluble and chelated form ---nutrients can get onto the leaves in as little as 15 minutes. Uptake is also higher when temperatures are warmer (but not too warm; this study had temps up to 95 F). Gaussoin’s takeaway from the morning discussion is: turf will take in nitrogen through the leaves, and superintendents should use a complement of products.

Stowell suggested that, much like Peabody and his boy Sherman, the members of the talk show audience, should take a trip in the Wayback Machine and go back in history to find out what’s going on with their turf. A case study at one golf course showed that the current turf problems originated when high levels of phosphorus were reduced to practically nothing over time. By looking at a current soil test and previous soil tests that covered nearly a decade, the superintendent was able to see the decline in nutrient levels over time that caused the problems with the turf.

Deficit fertilization over too long a period will cause the turf to “crash and burn,” and excessive fertility will “blow it up,” in Stowell’s words. The key to success is keeping the system level by maintaining Sufficiency Levels of Available Nutrients (SLAN) or Minimum Levels of Sustainable Nutrition (MLSN) (for more information on MLSN, go to www.paceturf.org). 

Kopec has done extensive research in Arizona on seashore paspalum, a turfgrass that was developed in Georgia. His experience in Arizona suggests that the iron recommendations from research in Georgia are inadequate in calcareous soil in Arizona. Kopec says that superintendents should lower the soil pH to make more iron available to the plants.