Irrigation and Root Growth
A key part of cultivating a resilient and healthy turfgrass culture is the encouragement and promotion of a healthy root system. I would define a healthy root system as one having both strong root mass (volume of roots) plus a system that has sufficient depth to reliably source water from the soil.
We can use irrigation as a tool to encourage the type of root growth that we see as most appropriate to our site and the surface and as a method of encouraging drought resilience. Deep, healthy roots are our aim, particularly after the challenging winter conditions that undid the valuable work that previous season’s aeration work developed.
Irrigating for longer spells, less often will encourage deep roots as the plant looks for water within the soil. Irrigation more often will provide the plant with a continual supply of water and therefore the turf will not push root growth seeking water and develop a shallow, surface-biased root system.
Irrigating less often and more deeply will contribute to a healthier root system across the course but there will be areas that dry out.
Height of Cut and Root Growth
As much influence on root growth can also be achieved by manipulating the mowing height. A longer height of cut, giving more leaf tissue, will allow the plant to produce a deeper root system. Additionally, when we aerate surfaces we are producing countless opportunities for ease of access for root growth.
Club Championship and PGA Greens
A short explanation about greens preparation for the Club Championships and PGA National Championships will be valuable for everyone to understand the standards of tournament golf and the limitations of setting up a golf course to produce putting surfaces of a very high standard.
Our preparation for the putting surfaces began in earnest a week before the Club Championships with brush cutting and double cutting beginning on the Monday before CC.
From the Wednesday before CC until the final day of PGA National (nine consecutive days), the greens were double mown in cross directions with one mower having a front-mount brush to stand up the turf. Additionally the greens were rolled on each of these days, again nine consecutive days. The table below gives an illustration of the processes and the manpower required for the fortnight that was dedicated to preparing the greens.
Irrigation and Root Growth
The height of cut was a modest 3.6mm, moisture levels were maintained to allow shots to hold and some pitchmarks were apparent but we needed to irrigate roughly every second night. The downpour we had on Monday after C’Championships certainly moistened the profile and allowed a lot of give. The green speed was taken early mornings shortly after mowing and rolling and was between 10.5 and 11, slightly faster than what would be produced at The Open.
Producing a surface like this is certainly achievable on a regular basis but it comes with the following requirements and consequences:
- Manpower requires three team members dedicated to mowing and rolling every day, plus an addition team member to change holes, check moisture and take green speed readings
- Continual rolling will contribute to surface compaction that will compromise root development and will require more regular aeration and decompaction actions
- Continual rolling will contribute to surface compaction and may reduce irrigation infiltration that again will require more regular aeration.
- Continual double mowing imposes additional mechanical stress on greens which may lead to a higher incidence of disease.
