Before you spend a lot of money and time renovating or remodeling the greens at your golf course, wouldn’t it be great to peer down below the surface to see how the rootzone and drainage are working. A look below the surface can provide insight into green make-up and performance. Sub-surface investigations when performed properly can be minimally invasive, yet provide insight and guidance for golf course maintenance and renovation activities.    

This article provides information about soil profiling, a series of techniques to study the inner working of a turfgrass system. A soil profile examination consists of taking an undisturbed sample from the soil. By providing a cross section of the turf system, the profile acts as a window into the inner workings and make-up of the green.  Soil profile analyses can be a simple visual check performed by the golf course superintendent or an in-depth analysis performed by a testing lab or agronomist.    

The ability to visually observe the current condition of the green is what makes soil profiles so powerful. Problems such as layering (which disrupts water movement) are often evident once the profile is evaluated. Additionally, inconsistencies in green depths, migration of sand into the gravel layer, and root growth problems and successes can also be identified.

In its simplest form a profile analysis consists of pushing a probe into the soil, withdrawing the probe from the soil, then observing the soil for stratification or other issues. A variety of soil profilers are commercially available. These devices typically have sampling depths of 10 cm to 30 cm, and allow for simple sampling and easy replacement of the removed soil.

Figure 1 shows profile samples taken with two different types of samplers. These samplers are great for routine observations of the soil profile. The smaller tubular samplers typically provide a fast method for observing soil conditions. Wedge samplers provide a bigger viewing area.  With both of these types of samplers you can observe issues such as soil layering and organic build up at the green surface. The larger profilers may also provide additional visuals such as root structure and pest presence.  

Diagnostic cores are a more detailed version of soil profile analyses. In this technique soil profiles are taken at the golf course, and then sent off to a qualified physical-testing laboratory for the diagnostic analysis.  When a golf course is experiencing problems with drainage or turf growth, core testing can often pinpoint the cause of these problems. The test reports can provide detail on past maintenance practices, the current condition of the soil and turf, and provide recommendations for proper maintenance techniques to encourage deep root growth and excellent air and water movement. In addition, diagnostic core analysis is used to obtain information for greens that are performing well. This information can be used to guide routine maintenance practices (e.g. topdressing and core aerification) and as a baseline for comparison in the future.

Diagnostic cores are especially useful when considering remodeling. The test results can help to provide guidance as to whether regrassing, minor renovations (removal of surface layers), or complete rebuilding of greens and drainage are needed.

Diagnostic core sampling is similar to other soil profiling techniques, but it does not require any specialized tools or equipment.  The core sample is typically collected by the golf course maintenance staff, using a piece of beveled PVC pipe, a hammer, and a piece of lumber (figure 2).  Sample collection is achieved by driving the beveled end of the PVC pipe through the green profile until subgrade is penetrated.  The pipe is then removed from the soil, packed very tightly, and shipped to the laboratory.