PHOTO A: This bare spot on the putting green is due to geothermal activity. In Rotorua, New Zealand, the earth’s crust is thin, and signs of geothermal activity (geysers, bubbling mud pools, fumaroles, steam and gas coming from the ground) can be seen throughout the area. The golf course has many of these features, which can appear at any time and location. It’s difficult to grow turfgrass on or near these areas of activity because of high soil temperature, steam and sulfuric gases. The area on the putting green could get worse and develop into a larger mud pool, as shown in the second photo (this mud pool was in the center of a fairway).

Photos courtesy of Douglas Linde, Ph.D., professor of agronomy, Delaware Valley College, Doylestown, Pa.