Netafim SPINNET Handbook page 11

MICRO-SPRINKLER/EMITTER SELECTION
EXAMPLE
a
Net application Average net
measurements application
[mm] [AVG]
5.14
5.06
5.02
4.99
4.87
4.87
4.83
4.77
4.75
4.73
4.70 91.35 / 20 = 4.57
4.62
4.41
4.40
4.38
4.26
4.25
4.12
3.82
3.36
Sum: 91.35
*Application deviations are always recorded as positive numbers, whether the result is lower or higher
than the average net application [AVG].
Distribution uniformity (%DU)
The %DU is a measurement of uniformity, based on comparison of the driest 25% of the surveyed area
with the overall average net application, as a percentage.
%DU = (average of the lowest 25% / overall average) x 100
A perfectly uniform application is represented by a DU of 100%.
A less uniform application is represented by a lower percentage:
For micro-sprinkler/emitter irrigation of protected crops:
90% or higher Excellent uniformity
85% to 90% Very good uniformity
Lower than 85% Acceptable for certain low-value crops only
b
Measurements [mm] -
average net application
= application deviations*
Sum: 7.29
c
Average
deviation from
average net
application
0.57
0.49
0.45
0.42
0.30
0.30
0.26
0.20
0.22
0.24
0.23 7.29 / 20 = 0.36 1 - (0.36 / 4.57) = 92.12
0.05
0.16
0.17
0.19
0.31
0.32
0.45
0.75
1.21
UPSIDE-DOWN MICRO-EMITTERS HANDBOOK 11
d e
%CU