Evaluation of Invigorate for Improved Infiltration on Sand Greens

March 14, 2005

Summary: A study was conducted to evaluate the effect of aerification and application of the soil amendment, Invigorate, on infiltration, turf quality, root mass and length, soil chemistry, and soil gas levels. Key results include:

• Infiltration rate was consistently highest in plots that received a regime of monthly Invigorate treatments PLUS a hollow tine and verti-drain aerification in April, and a small tine aerification in June (treatment 2). In contrast, plots that received only Invigorate applications, but no verti-drain aerification (treatment 4), did not differ significantly from the non-treated check in infiltration rate on any of the dates tested. The positive effects of high infiltration rate were mirrored in the results on root length and soil nutrient levels, but were not correlated with turf quality, root mass or carbon dioxide ratings.
• The improved infiltration rate and increased root length observed in treatment 2 were not mirrored in results obtained for turf quality, root mass or carbon dioxide readings. The highest quality turf was observed for treatment 3, which received a combination of aerification treatments, but was not treated with Invigorate. Similarly, the highest root mass readings were taken from plots that were not treated with Invigorate; root length and root mass were in fact not significantly correlated with one another.
• Soil chemistry results indicate that higher infiltration rates resulted in lower levels of ions such as sodium, magnesium, sulfate, iron, manganese and aluminum. This resulted in lower soil electrical conductivity values, a potential benefit of increased infiltration rates.
• The overall lack of correlation between turf quality and any of the many measurements taken in this study indicates that there is no single tool or measurement that accurately reflects the complex interaction of variables that contribute to turf quality.
• When used in conjunction with aerification, monthly applications of Invigorate resulted in improved infiltration rates. However, aerification - particularly a springtime deep tine aerification - was critical to improved infiltration rates. When the deep tine aerification step was omitted, Invigorate applications did not result in any appreciable benefits. For this reason, Invigorate should be used only in conjunction with aerification, and not as a substitute for it.

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Principal Investigators: Wendy Gelernter, Ph.D. and Larry J. Stowell, Ph.D., CPPP, CPAg

Cooperator: Candice Combs, Balboa Park Golf Course

Sponsor: Milliken