RMGCSA Techinical Article - 10.07.04
A Cure for Localized Dry Spots
When I was first approached by Western Pozzolan in 2001 and was asked to place their volcanic mineral Pozzolan on my golf course, I was extremely skeptical. Golf Superintendents have pretty much “seen it all” and this Pozzolan product appeared to be another in a long line of “miracle cures”. The representative from Western Pozzolan was very persistent, so I agreed to place a small amount of product on the worst localized dry spot I could think of, without much expectation of success. .
After applying the product, I went about my normal day-to-day business and all but forgot about the test. Then, one day several months later, I drove by one of the spots and noticed that the area, which previously had been completely devoid of grass due to persistent dryness, had a fresh crop of green and healthy grass. I remembered the Pozzolan test and realized that, much to my surprise, the claims made by the company were, in fact, true. Since the first trial, I have placed the product on areas that suffer from compaction, localized dry spots, and hard to maintain slopes with continued success.
At the time of the first test, Western had little in the way of analytical evidence or studies to suggest that this material might make an excellent soil amendment. In January, 2002, analytical testing of the material was initiated. Thomas Turf Services, in addition to others, was selected as the laboratory to perform the required physical testing on the material as a soil amendment. Thomas Turf Services was the second lab in the nation to be accredited by the American Association for Geotechnical evaluation of putting green materials. Mr. Thomas has provided soil testing, turf management, and greens mix design to client’s world wide for over 30 years.
“The physical measurements of the pozzolan showed it to have acceptable saturated hydraulic conductivity of 10.9 inches per hour which is in the normal range of 6-12 inches per hour recommended by the USGA. The pozzolan retained 62.1% moisture at 30 cm tension. The pozzolan had a low bulk density of 0.81 g/cc and a low particle density of 2.49 g/cc. The pozzolan had a high 67.7% total porosity, a very high 50% capillary porosity and an acceptable 17.7% air-filled porosity.”
“The physical measurements show that the pozzolan will have a high amount of total porosity and retain a very high amount of water. Therefore, the pozzolan will be effective in increasing the capillary porosity of a rootzone sand. The net result of incorporating Pozzolan into the soil profile should be three fold:
1) water loss due to runoff will be less due to increased infiltration into the soil
2) a reduced need for hand watering of intensively managed turf
3) the routinely scheduled irrigation frequency may be reduced due to the greater storage capacity of the amended soil.”
Compared to many other soil amendments on the market today, Pozzolan not only absorbs more moisture under tension (as in a putting green root zone), but more importantly, makes this adsorbed moisture available to the root zone in advance of the theoretical “wilt point” or at the point when a Superintendent will irrigate the turf.
In addition, the USGA recommends testing the stability of golf course green building materials. This is accomplished by using the ASTM C-88 Sulfate Soundness Test. Greater than 12% degradation over a 20-year period is unacceptable. Lassenite Soil Amendments far exceed this recommendation by degrading less than 3%.
It appears that pozzolan can be considered a permanent addition to the soil. Although additional testing is required, such as further University studies, etc. the application Lassenite Pozzolan has proved itself as an extremely beneficial tool in turf management.
Glenn Quirk
Director of Golf Maintenance
Braemar CC, Tarzana CA