TDR 300 Moisture probe

The middle of summer 2013 we purchased a TDR 300 Moisture probe, this is a state of the art tool that assists in the management of the water content within the subsoil of our greens. Why is water content important? The most important reason is that it is crucial to the health of the turf. The grass species at Ponteland is poa annua and to manage this grass type to its highest standard it is important to maintain a steady and constant water content. Using the TDR we insert the 2 pins into the turf to take a reading of Variable Water Content (VWC). We take measurements in 9 different places evenly spread around the green as well as any areas that have a history of being dry. We maintain our VWC between 30-35%. It is impossible to look at a green and tell what the VWC is, on our greens heat stress will start showing at around 25%VWC and this is where greens performance starts to drop. A reading below 25%VWC is bad for our grass type because ‘wet/dry cycles’ cause stress and everything we do to maintain the greens stresses the plant i.e. Cutting, rolling, brushing. When the plant becomes stressed we then have to relieve that stress by taking an operation out of our maintenance plan.

Now we know the VWC we can set up the irrigation for the day. Whilst taking readings we note down if a green would benefit from the automated system which covers the whole green or hand watering is required to spot treat hot spots on the greens. If we have 3 readings across the back of a green 33%VWC, 27%VWC and 35%VWC using the automated system to raise the lowest reading 3% also raises the higher reading 3% in this case hand watering is best to bring the 1 area back into the zone. Over the weekend when our staff levels are minimal hand watering isn’t possible so by Sunday a whole greens VWC can drop and this is where the automated system is used the most.

Water content also has a big effect on greens speed, there are many ways to create speed on a putting surface but one thing that always remains consistent is the VWC. If the VWC is too high then excess moisture will slow the ball down, if it’s too low the leaf can curl up into survival mode creating an uneven surface. The speed will be fine but the quality of ball roll will be reduced. This is where the TDR is so important leading up to a competition, it is such a fine line we tread between getting the greens fast and smooth or over stressing them and producing unrewarding greens.

The TDR 300 has been a fantastic aid since it’s purchase and I would consider it an essential tool for modern day maintenance.


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