Golf Course Products and Services

Looking for answers to specific questions about agronomy? Pat Gross is here to help.

Pat retired from the United States Golf Association (USGA) after a 28-year career as an agronomist and director of the Western Region of the Green Section. During his tenure with the USGA, he completed more than 2,000 on-site consulting visits with a focus on providing practical information to help golf courses conserve water and improve course conditions.

Take advantage of Pat’s in-depth knowledge and experience in the golf industry by submitting your questions below.

Recent Question

ET-Based Irrigation

Q: Is irrigating according to ET the best way to determine how much water to apply to the turf?

A: ET (evapotranspiration) is a measure of how much water evaporates from the soil and transpires through the turf over a 24-hour period. It is a calculated value based on several factors including solar radiation, temperature, humidity, and wind. ET is measured in inches of water. How does that translate into gallons? A 1-inch depth of water covering 1 acre of land (roughly the size of a football field) equals 27,154 gallons. ET is measured by local or on-site weather stations that collect and send the information to the central irrigation controller at the golf course maintenance facility that can then be used for programming the irrigation system.

ET is a good baseline measurement for tracking how much water needs to be added back to the turf as irrigation. Depending on the site conditions and the superintendent’s preference, irrigation can be scheduled each night to replace ET loss or accumulated over several days and applied as one heavy irrigation cycle. Both are valid strategies.

All superintendents know from experience that water demand varies throughout the golf course due to topography, sun/shade patterns, the types of turf and plants being irrigated, and other variables. It is unreasonable to expect that one ET measurement can apply equally throughout the golf course. The most practical approach is to use ET data as a basic guideline for average areas of the golf course, and then refine the irrigation schedule on sections of the golf course based on field observations, soil probe samples, in-ground soil moisture sensor data, and experience.