Page 16 - Transitioning Turfgrass

TRANSITIONING TURFGRASS

the results from over 6800 audits of landscape ir- (Dwomoh et al., 2014).
rigation systems pointing out that the most sprin- In conclusion, though many factors may affect
kler systems fell into the “fair” or “poor” category turf quality and efficient use of water, a starting
(DU < 59%). Very often the lower the distribution point is the high distribution uniformity obtained
lq
uniformity, the lower the irrigation efficiency due with good design and careful maintenance of the
to overirrigation to ameliorate turfgrass appear- system during the time.
ance of the driest zones suffering the least water
application. In fact, any degradation in turfgrass
will likely result in the increasing irrigation volume References
to the area. During audits in residential irrigation
systems, Thomas et al. (2002) found that, to Baum M.C., Dukes, M.D., Miller, G.L., 2005. Analysis of res-
overcome the poor water distribution uniformity idential irrigation distribution uniformity. Journal of irrigation
and drainage engineering, 131(4), 336-341.
related to inappropriate selection of sprinkler noz-
zles, the irrigation time was usually set too high, Carrow R.N., 2006. Can we maintain turf to customers’ sat-
resulting in overapplication of water. And over- isfaction with less water? Agricultural water management,
80(1-3), 117-131.
watering, besides wasting water and energy and
leading to environmental degradation, produces Connellan G., 2002. Efficient irrigation: A reference manual
for turf and landscape. Brunley College, University of Mel-
poor agronomic conditions for healthy turfgrass. bourne, Melbourne (VIC), Australia.
Other factors may influence distribution unifor- Dwomoh F.A., Shouqi Y., Hong L., 2014. Computation Model
mity. Baum et al. (2005), analysing the distribu- of Sprinkler Spacing and Layout. International Journal of En-
tion uniformity of residential irrigation systems, gineering Sciences & Emerging Technologies, 7(1), 481-489.
noted that sprinkler brand and pressure also af- Gómez-Armayones C., Kvalbein A., Aamlid T. S., Knox J.W.,
fected the uniformity values. In a field investiga- 2018. Assessing evidence on the agronomic and environmen-
tion conducted at five golf courses, Miller et al. tal impacts of turfgrass irrigation management. Journal of
(2014) found that the DU was 55% on average, agronomy and crop science, 204(4), 333-346.
lq
and the highest values were measured in the golf Mecham B., 2004. Using distribution uniformity to evaluate
course that presented very little pressure variation the quality of a sprinkler system. NCWC District, Irrigation
among sprinklers and sufficient sprinkler overlap. Association’s. Berthoud (CO), USA.
Pitts et al. (1996) listed, in order of frequency, the Merriam J.L., Keller J., 1978. Farm irrigation system evalua-
reasons that can be a cause of low DU values: tion: A guide for management. Utah State University, Logan
(Utah), USA.
lq
maintenance and faulty sprinkler heads, mixed
equipment type in zones (spray and rotor), exces- Monteiro J.A., 2017. Ecosystem services from turfgrass land-
sive pressure variations, and poor head-to-head scapes. Urban Forestry & Urban Greening, 26, 151-157.
coverage. Although distribution and redistribu- Pitts D., Peterson K., Gilbert G., Fastenau R., 1996. Field
tion into the soil of irrigation water are affected assessment of irrigation system performance. Applied Engi-
neering in Agriculture, 12(3), 307-313.
by many other factors, such as soil texture, slope,
thatch accumulation, turfgrass canopy, Straw et Straw C.M., Carrow R.N., Bowling W.J., Tucker K.A., Henry
G.M., 2018. Uniformity and spatial variability of soil moisture
al. (2018) found that volumetric water content and irrigation distribution on natural turfgrass sports fields.
DU is similar to catch can DU on the sand Journal of Soil and Water Conservation, 73(5), 577-586.
lq
lq
capped turfgrass sports fields. It would there- Thomas D.L., Harrison K.A., Reed R., Bennett R., Perez V.,
fore be necessary to simulate options of sprinkler 2002. Landscape and turf irrigation auditing: A mobile lab-
placement for the desired uniformities before oratory approach for small communities. ASAE Paper N.
installation on the field. However, several ana- 02-2247. American Society of Agricultural Engineers, St.
lytical tools able to give irrigation designers the Joseph (Mich.), USA.
ability to evaluate and compare different sprin-
klers, nozzles, spacing, combinations have been
developed, most of them in the last few decades

12