Abstract:
Field experiment was conducted to assess the actual water consumptive use
ET a, references water consumptive use ET 0 and crop factor Kc for cabbage under
micro-sprinkler irrigation (MSI), drip irrigation (DI), sub surface drip irrigation (SDI),
and furrow irrigation (FI). The experiment was conducted at a farm northern of
Baghdad (latitude 33 north and longitude 45 east) at autumn season 2009. The
experiment was designed according to RCBD in four replications. Time of irrigation
and amount of water applied were in accordance with soil moisture content and water
applied up to field capacity limit. Water balance equation was used to determine ET a
for plant growth stages (vegetative growth, leaves wrap, maturity and harvest).
Penman-Monteith equation was used for ET0 estimation. Cabbage crop factor was
calculated From ETa and ET 0 for each growth stage and for each method of irrigation.
The results indicated that ETa varied with irrigation systems. ETa were 406, 381, 365
and 393 mm.season-1 for MSI, DI, SDI and FI, respectively. Maximum ET a values
were at vegetative growth and maturity stages the relative values about 19% to 38% of
total ET a for all treatments. ETa decreased about 3% to 10% for DI and SDI compared
to MSI and FI. ET a increased by 3% in MSI comparing with FI. ET 0 value was 434
mm.season -1 during cabbage growth season. Kc values varied with irrigation systems
with 0.94, 0.88, 0.84 and 0.91 for MSI, DI, SDI and FI respectively. The maximum
value of Kc occurred at maturity stage with 0.965, 0.910, 1.141, and 1.140 for
irrigation treatment respectively. It is clear that micro-irrigation systems reduced
cabbage ET a at stages growth so it reflected on Kc values.
