Two field experiments were carried out at Agriculture Secondary School
Farm in Kafr EI Sheikh Governorate, in the two successive seasons, 1999-2000 and
2000-2001, to study the effect of two irrigation systems, i.e. furrow and bed systems
and three water stress levels (50, 65 and 80% depletion of available soil moisture
content) on sugar beet yield, water saving and water use efficiency .A split plot design
with four replicates' was used in this study. The obtained data showed that, Irrigation
system not affected the sugar beet root yield, while the water stress treatments have
highly significant effect. Also the same trend was obtained on sucrose percentage
.The highest values of water applied were recorded with the furrow irrigation system
and 50% depletion of available soil moisture content. While the lowest value was
recorded with bed irrigation system and 80% depletion of available soil moisture
content. The average values of water saving were 20.04 and 34.99% under bed
irrigation system treatment and 80% depletion of available soil moisture content
respectively: The averaqes seasonal water consumptive use of sugar beet plant were
2044.35 and 1.173.36 m3J fed. under furrow and bed irrigation systems, respectively.
On the other hand, these values were 2216.55,1952 and 1558.05 m3/fed. under water
stress of 50,65 and 80% depletion of available soil moisture content. Treatments of
bed irrigation system and water stress of 80% depletion of available soil moisture
content achieved the ,highest value of water use efficiency. Data of soil moisture
extraction revealed that sugar beet.plant roots under moisted soil condition extracted
a large amount of water from the surface s6illayer (30 cm depth) and a little amount
of water from' deep soil layer (45-60cni), while the plant roots penetrated soil profile
and tend to extend for more depth under dried soil conditions to obtain its need of
water from deeper layer. Modified Penman equation can be used with the value of
0.78 for crop coefficient to calculate the evapotranspiration of sugar beet plant grown
in the North Nile Delta.