Pogo Turf Pro System Manual page 79

Moisture – Water Fraction Volume
Moisture is one of three direct agronomy variables that the POGO measures. Unlike other sensors, the POGO's Hydra Probe II sensor requires no
calibration and will not skew moisture measurements when EC, bulk density, turf/soil type, or other changing dynamics in the turf system occur.
So you are assured that a given moisture measurement today (i.e. 22%) represents the same moisture condition at any other time you see that
percentage. This is vitally important for making decisions.
The POGO's moisture measurement is called 'Water Fraction Volume' or 'WFV'. It is also considered to be volumetric water content and is a
measurement of the available moisture in the turf and soil medium as the turf sees it. Every turf system has a given amount of pore space which
is precisely measured in a unique lab analysis (see 'The POGO Turf and Soil Analysis' section of this manual). POGO is measuring the amount of
water that fills this pore space. Since several factors affect the amount of pore space in a turf system, there is no optimal moisture that applies to
everyone.
For instance, for every 1% increase in organic matter, this results in a 10X increase in water holding capacity (and salinity holding capacity). If you
compact that organic matter into a dense layer even as minimal as 2 or 3 mm, this increase in water holding capacity increases even more. Ideally,
turf will perform best when half of the pore spaces are filled with water (moisture measurement) and half are filled with air with no limiting
layers preventing movement of moisture through the system and air in and out of it. If we have 45% total pore space in a turf system and POGO is
measuring 40% moisture, you have very little air movement in that system. This will lead to anaerobic conditions, lower disease resistance or
recovery capabilities, black layer development and poor surface conditions.
Moisture and air exchange ratios are of the highest importance in turfgrass management. This one focus can be the most influential factor that
determines how your turf performs...no matter where you are in the world, and it is often the blame for many turf failures. Further, since a sand
can act like a clay when the rootzone is not consistent or contains variations in structure or texture or has organic matter confined in one region
as is usually the case due to the unique nature of turf growth, optimum moisture values cannot be generalized.
You can find your optimum moisture value by knowing what your turf systems physical (and chemical) qualities are as we provide with the POGO
Turf and Soil analysis. Or you may choose to simply observe your values over time and find the 'sweet spot' by correlating routine measurements
with conditions.