Submitted to: Meeting Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 8/3/2015
Publication Date: 8/11/2015
Citation: Allred, B.J., Martinez, L.R., Gamble, D.L., Mccoy, E. 2015. Mapping soil water content on golf course greens with GPR. Ohio Turfgrass Foundation Research Field Day Proceedings, August 11, 2015, Columbus, Ohio. p. 23-24.
Technical Abstract: Ground-penetrating radar (GPR) can be an effective and efficient method for high-resolution mapping of volumetric water content in the sand layer directly beneath the ground surface at a golf course green. This information could potentially be very useful to golf course superintendents for determining which parts of the green are draining properly and which parts are not. The GPR method involves directing an electromagnetic radio energy (radar) pulse into the subsurface, followed by measurement of the elapsed time taken by the signal as it is travels downwards from the transmitting antenna, partially reflects off a buried feature, and is returned to the surface, where it is detected by a receiving antenna. Once the radar pulse two-way travel time (down and back) to a buried feature (i.e., base of sand layer) is measured, the bulk radar velocity of the soil volume from the ground surface down to the buried feature's depth can then be calculated if the depth to the buried feature is known, along with the separation distance between the GPR transmitting and receiving antennas. Next, the soil dielectric constant can be calculated from the value determined for the soil radar velocity. Finally, various empirical equations can be employed to compute a bulk soil water content from the soil dielectric constant. This GPR approach for sand layer water content measurement was tested at two golf course greens located near Columbus, Ohio. At both golf course greens, the sand layer water content measured with GPR was quite similar in magnitude and spatial pattern to the magnitude and spatial pattern of sand layer water content measured with time-domain reflectometry (TDR). Consequently, these field results clearly indicate that this GPR based approach can accurately measure sand layer volumetric water content on golf course greens.