The sixth green at Omaha (Neb.) Country Club with an inserted cup cutter sleeve filled with water for a simple field water-infiltration test. Photo by Brian Mavis
We all know water is essential to a plant’s survival. In golf, too much water can lead to soft playing conditions and invite the potential for increased disease pressure. While withholding water can positively impact playing conditions, doing so for extended periods can cause wilt, drought stress and decline in turf quality. The ability to manage moisture is arguably the most important factor in turf performance. Finding the correct balance is a large part of the art of greenkeeping.
One of the keys to managing moisture levels requires a putting surface with good infiltration rates. It is important to have a soil profile with adequate-sized pore spaces that create pockets of air and the ability for water to flow easily through the soil profile. Desirable porosity levels promote a healthy root system, aid in efficient nutrient uptake, reduce the chance of salt accumulation and promote consistent playing conditions. Modifying pore space can be achieved through cultural practices such as topdressing and aeration, which reduce organic matter and facilitate water movement throughout the soil layers. Penetrant wetting agents can also aid in the movement of water.
How do we know what we are doing is working? How can we communicate to members, green committees and players that aeration is a necessary process, providing a positive impact on their most valuable asset?
Necessary tools to complete the water-infiltration field test, from left: stopwatch, cup cutter sleeve, rubber mallet and ruler. Just add water. Photo by Pete McAfee
At Omaha (Neb.) Country Club, our goal is to provide championship playing conditions with firm and consistent putting surfaces, daily. In late 2022 and early 2023, we started to notice a change in our putting surfaces when water, whether from rain or irrigation, began pooling or ponding at the surface. We consulted with Brian Mavis of Mavis Consulting to aid in our effort to test and analyze all aspects of our program. After in-depth testing, including an analysis of the complete physical properties of our soils and inputs, irrigation water and our porosity levels, we were able to see that our soil profile had changed, and our infiltration rates decreased. This caused a decrease in oxygen levels and increased water retention at the surface. One of the tools in our maintenance program moving forward included measuring infiltration rates and collecting and comparing the data throughout the season. We were able to effectively communicate to our green committee using spreadsheets and charts to show improvements to our water infiltration rates as the season progressed.
We began to spot-check infiltration rates during the season with tools we already had on hand: a cup cutter sleeve, rubber mallet, stopwatch and ruler. Commercially made infiltrometers are also an option if desired. The following is a step-by-step guide on how to conduct your own infiltration test in the field.
Omaha CC’s No. 6 green during a visit from Brian Mavis of Mavis Consulting. The purpose of the visit was to help check the water infiltration rates of two spots, one with healthy-looking turf and one with unhealthy-looking turf, in an area of high traffic. Photos by Brian Mavis
Step 1: Insert the sleeve into the putting surface so that 41⁄2 inches remain above the turf. We marked the outside of the sleeve to aid in this step. Try to minimize any lateral movement to ensure adequate seal with the edges. If the final rate is extremely high in comparison, re-test.
Step 2: Fill with water to the top of the sleeve and wait five minutes. This step charges the testing spot to ensure saturation of soil.
Step 3: Fill with water to the top of the sleeve and set a timer for 15 minutes.
Note: If water completely ran out during the 15 minutes, refill immediately back to the top and include 41⁄2 inches in your total measurement in Step 4.
The author installing the cup cutter sleeve into the green. The black line on the sleeve indicates how far into the putting surface the sleeve needs to be so it can hold 4 1⁄2 inches of water.
Step 4: At the end of the 15 minutes, measure with a ruler the amount of water that has left the sleeve. (We will use 7 inches as an example.)
Step 5: Multiply the measurement of water that left the sleeve (7 inches) by 4 to obtain the infiltration rate for one hour (example: 7 x 4 = 28 inches per hour).
Step 6: Carefully push the core out of the sleeve with the handle of the rubber mallet and repair plug as needed.
Data from the tests were put into a spreadsheet, which was consulted when making decisions on when/if cultural practices were needed.
Initially, we tested all 21 putting greens bi-weekly and recorded the data. As the golf season progressed, we tested only six greens for efficiency. We tested two random spots per green, one at the front and one in the back, and took the average of the two. This data was then entered into a spreadsheet, which allowed us to make educated decisions on when or if cultural practices were needed. We ended up eliminating a planned needle tine aeration in September as we felt our infiltration rates were adequate enough to get us to our scheduled fall deep tine aeration.
This field test is not a replacement for laboratory testing but will give golf course superintendents a fairly good idea if water is moving through the profile. A decision can then be made on whether cultural practices such as needle tine or deep tine aeration should be introduced to improve rates. We continue to use accredited laboratories annually to confirm our programs have a positive impact on our soil profiles throughout the golf course.
Pete McAfee, a four-year GCSAA member, is an assistant superintendent at Omaha (Neb.) Country Club, working with Eric McPherson, CGCS, the GM and director of green and grounds and 31-year association member.