Page 15 - Transitioning Turfgrass

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6 ETS Field Days
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High Distribution Uniformity of

Irrigation Systems to Ensure Turf

Quality and Efficient Use of Water

Lucia Bortolini, Dept. Land Environment Agriculture and Forestry (TESAF) - University of Padova (Italy)

A controversial issue about lawns is related to their to evaluate it. DU emphasizes the areas which
lq
high water consumption, although their capacity receive the least irrigation by focusing on the low
to provide many ecosystem services is widely rec- quarter area, typically by placing catch can de-
ognized and it is well known that turf is an irre- vices across an irrigated area and is calculated
placeable surface for recreational sports/activi- using the following equation:
ties (Monteiro, 2017). Without water their benefits
may be reduced or annihilated but high-quality DU = Average low - quarter depth of water received
standards in turfgrass can be maintained also re- lq Average dept of water received
ducing water irrigation volumes (Carrow, 2006).
Different studies show that in most cases, under DU is often used as a basis to judge the quality
lq
moderate levels of deficit irrigation (50%-60% of a turf irrigation system and it well describes the
of actual evapotranspiration), turf quality can be performance of an irrigation system. Even if site
maintained at an acceptable level but with lower condition may alter the performance during op-
water consumption compared to irrigating back eration, distribution uniformity is in large part es-
to field capacity (Gómez-Armayones, 2018). tablished during system design. The American Ir-
To ensure efficient irrigation, or to reduce water ir- rigation Association indicates the catch can DU
lq
rigation volumes, it is necessary to apply uniform- values to describe the quality of irrigation system,
ly the appropriate water amount to plant and soil ranging from excellent to poor, and sets the min-
in correct timing, without wastage through runoff, imum values for fixed spray heads (55%) and ro-
deep percolation, wind drift and direct evapo- tary sprinklers (70%). Mecham (2004) reviewed
ration (Fig. 1). In summary good irrigation is the
efficient application of the right amount of wa- Good Irrigation
ter at the right time in the right place (Connellan,
2002). For the most effective results, uniformity Correct Correct Uniform No
and efficiency must work together. Only with a depht timing application losses
high distribution uniformity it’s possible to have a
high irrigation efficiency without losses and able to
ensure the right amount of water to all the plants,
basic condition to have a high-quality turfgrass.
Distribution uniformity indicates the uniformity
of application throughout the field and the Low
Quarter Distribution uniformity DUlq (Merri- Figure 1 The four key principles of good irrigation practice
am and Keller, 1978) is the more suitable index (Connellan, 2002).

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