Wetting agent program and irrigation effects on putting green performance

Golf course superintendents often use wetting agents and weather station data to conserve water. Irrigating based on evapotranspiration (ET) losses will help ensure an appropriate amount of water is available to maintain visual turf quality while keeping the putting surface firm for desired ball roll and shot holding characteristics. The objective of this research is to evaluate the effectiveness of commonly used wetting agents while irrigating at various levels of replacement ET on a sand-based creeping bentgrass (Agrostis stolonifera) putting green.

Irrigation treatments were applied at 50 percent, 75 percent, 100 percent and 125 percent ET replacement combined with six wetting agent treatments applied to each irrigation regime. Turf quality and color declined significantly when irrigation was applied at less than 75 percent ET. Among irrigation treatments, plots irrigated at 50 percent ET had more localized dry spots (LDS) than any other plots. Similarly, the untreated control plots had more LDS than all wetting agent treatments, regardless of the irrigation level.

Volumetric soil moisture evaluations at various depths indicated that the use of wetting agents did not affect the overall volumetric water content average, but improved uniformity of rootzone moisture across all irrigation levels. Wetting agent treatment did not have a significant effect on surface hardness when sufficient irrigation was applied, but decreased hardness at the 50 percent ET irrigation level. There were no effects of irrigation or wetting agent on golf ball roll distance. A favorable playing surface is attainable using less water when wetting agents are applied.

Ethan D. Charles, Douglas E. Karcher, Ph.D., and Michael D. Richardson, Ph.D.,  Department of Horticulture, University of Arkansas, Fayetteville, AR. Ethan Charles can be contacted at echarles@uark.edu for more information.