PERFORMANCE OF GRAPEVINES UNDER IRRIGATION SYSTEMS - Management, Performance, and Applications of Micro Irrigation Systems - page 265

TABLE 5 Irrigation efficiency for different irrigation systems.

Distribution
effi ciency,
%

Irrigation ef-
fi ciency
%

Irrigation
systems

Application effi ciency,
%

2002-2003

Drip 94.0 90.0 84.6

L-H Bubbler 90.0 89.0 80.1

Gated pipes

81.0 80.0 64.8

2003-2004

Drip 95.0 92.0 87.4

L-H bubbler 92.0 88.0 80.9

Gated pipes 80.0 79.0 63.2

L-H = Low head.
Irrigation effi ciency = Application effi ciency × Distribution effi ciency.

20.2.3 IRRIGATION SCHEDULING
Irrigation interval was 4 days for drip and low head bubbler irrigation systems, while
it was 7 days for gated pipes irrigation system. Irrigation interval was calculated using
Eq. (6). The Eq. (7) was used to estimate net water depth applied per each irrigation
(mm).

I = d/(ET c ) (6)

d = MAD × WHC × Rd × P (7)

ET c = ET o × K c (8)

where: d = net water depth applied per each irrigation (mm); WHC = (AW)(B.D) =
water holding capacity, (mm water/m soil); MAD = management allowable deficit of
30 and 50% for drip and gated pipe irrigation, respectively; Rd = effective root zone
depth (m); P = percentage of soil area wetted (%); ET c = crop evapotranspiration (mm/
day) given by Eq. (8); ET o = reference evapotranspiration (mm/day); and K c = crop
coefficient

20.2.4 FERTILIZATION AND FERTIGATION
Fertilization scheduling was followed according to the recommended doses through-
out the two growing seasons (2002/2003 and 2003/2004) for grapevines in each ir-
rigation system by fertigation technique. The amounts of fertilizers were 350 kg/fed
of ammonium sulfate (20.6%N) and 225 kg/fed of potassium sulfate (48.7% K 2 O).