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Soil Moisture Probes

Thursday 13, Dec 2018

Australia’s leading agronomic expert John Neylan delves into use of soil moisture senses and how to get the most out of them and also looks at some recent trial work looking at the potential of fraze mowing as a non-chemical means of controlling Poa annua.

Soil moisture monitoring using portable probes has become commonplace over the past few years for determining soil moisture and for scheduling irrigation. This has added an extra level of precision in understanding the relationship between soil moisture content, turf health and playing surface quality.

Soil moisture probes are but a tool, albeit a very useful tool. The power of the device is in understanding the numbers the device is generating and then relating it back to a wide range of variables including weather, irrigation programming, turf health and surface performance at your location. What the soil moisture probe provides is a reasonably repeatable measure that can be related to key maintenance practices.

At the 2018 Australasian Turfgrass Conference in Wellington, New Zealand, a Plenary session paper was presented by Carmen Magro entitled ‘Optimising turfgrass performance using precision monitoring technology’.

The presentation highlighted the importance of monitoring soil moisture content and how the data can be related to changes in turf health. It was unfortunate that the presentation only concentrated on one specific device and didn’t provide a broader overview of the available technology. 

There have been frequent comments made over time that different technologies have various attributes and/or weaknesses that may make one device preferred over another. This was implied in Magro’s presentation with no detail behind it. It therefore had me thinking that it may be useful to review the use of soil moisture sensors in these pages and what turf managers need to consider when using such devices.

Sensor types

In a review of Michigan State University’s Turfgrass Information File (which all AGCSA members have access to), the information regarding the comparison of soil moisture probes is very limited. Consequently, I had to look towards agriculture and horticulture to obtain a better insight into this technology.

Interestingly, this further emphasises the lack of research into some fundamental areas of turf management where we assume that a tool we are using actually means something.

 

Continue reading about Soil Moisture Probes, and Fraze Mowing research into Poa Annua control

 

     


The addition of soil moisture sensors into the turf manager’s arsenal has helped to add an extra level of precision in understanding the relationship between soil moisture content, turf health and playing surface quality

There are basically two groups of sensors:

  • Water potential sensors, such as tensiometers and granular matrix sensors which directly interact with the soil matrix.
  • Soil moisture sensors that give a percentage or relative content of soil moisture (water content sensors).

In turf applications, the first soil moisture sensor that was widely used in turf was the matric or soil water potential sensor developed by Ken Cuming. This device measures directly the change in soil water potential by responding to the capillary tension in the rootzone, which in turn is related to soil water availability. The Cuming sensor was a considerable advancement over the gypsum block device because it compensated for changes in soil salinity.