We took a core from #7 green in March and sent it to the International Sports Turf Research Center(ISTRC) for evaluation of the soil's physical properties. We chose to do the test to evaluate where the greens are now and also to establish a benchmark that will enable us, through annual testing, to evaluate the effectiveness of each year's cultural practices.
The report that we received contained two sets of data. The first set of data consists of the physical evaluation, the evaluation of the root systems, and the measurement of the organic matter by layer. According to the report, #7 green is in good physical condition for its age and turf type. The infiltration rate was excellent and the air capacity to water porosity ratio was approximately 1:1, which is ideal. The organic matter in the top inch was 2.35%, which is in the acceptable range of 1.5%-2.5% for well-drained greens, but is a little higher than we would like and something that we will have to continually monitor in the upcoming years. The organic material in the next 3" was fine. In regards to the root system, the root mass was acceptable, but the feeder roots were shorter than desirable.
The second set of data contains the textural and particle size analysis. The texture of our sample had a favorable matrix of soil types as well as a good distribution of particle sizes throughout the profile. This is a result of the greens being constructed on a good mix as well as a quality topdressing sand being used during light topdressings and to fill holes following core aerifications.
The agronomist reported that the physical properties of the greens resembled 4-5 year old greens as opposed to the almost 12 year old greens that they are. He attributed that to the cultural program that the greens are on and emphasized the importance of staying on that program or one similar. Furthermore, he provided the general recommendation of an aerification program that targets at least 15% annual surface area displacement in conjunction with regular ventings to keep the root zone opened up and breathing. This is consistent with the program we have in place and will continue to use in the future.
In summation, this test is basically about the nature and composition of pore spaces in the soil and the contributing factors. Those pore spaces are the lifeline of the grass as they allow the infiltration of air and water into and through the soil profile, as well as permit the release of carbon-dioxide rich soil gases, which can be very harmful to the grass. Without proper pore spacing, the plant will be very limited in its ability to obtain water, oxygen, and nutrients. As aforementioned, the pore space on the sampled core was ideal. The biggest concern from the report was the percentage of organic material in the top inch of the profile, which is common in older greens. It was still in an acceptable range, but we must focus on keeping that number in check through our current aerification program as well as increased light topdressings.
In closing, although we treat all the greens the same, it is important to remember that this test was performed on one plug taken from one green. We assume that this is a good assessment of the soil profile of all greens, but will not have a great understanding of just how accurate that it is until we test another green, which we intend to do next year. Starting next year, we plan on testing one location on two greens every year. We will use the same location on those two greens each year as well. This should greatly improve the accuracy of the results and be a wonderful tool to help us continually evaluate the effectiveness of our agronomic program on greens.
