Two field experiments were conducted at Sakha Agric. Res. Station, Kafr EI-
Sheikh Governorate during the summer seasons of 1999 and 2000. The situation lies
and represents the conditions of North Nile Delta. The aim of this study was to find out
the effect of different irrigatien intervals and zinc foliar spraying on maize and cotton
yields as well as some water parameters. In additien to define a simple equation te . predict contribution of water table to crop water needs fer such crops under study in
North Nile Delta. A split plot design with four replicates was practiced. The irrigatien
intervals; 12, 18 and 24 days occupied the main plots. While zinc foliar spraying;
control, 0.05% and 0.1% Zn as EDTA were arranged in the sub plots. The obtained results could be summarized as follows: The highest mean values of beth maize grain and seed cotton yields were
obtained under irrigatien every 18 days and zinc foliar spraying of 0.1 % as
EDTA. The interaction between the stated treatments resulted in highest yields
per each unit of seasonal water duities as so called maximum irrigatien
efficiency. Average values of seasonal soil moisture depletion (S.M.D.) fer maize were
51.33, 48.85 and 41.51 cm. under irrigatien intervals 12, 18 and 24 days,
respectively. The correspondinq values of S.M.D. fer cotton were 68.77,57.25
and 51.17 cm. fer the previously treatments. The water table contribution to water use of maize was 14.13, 16.54 and
18.13% under irrigatien intervals of 12, 18 and 24 days respectively. Under shallow water table conditions, the irrigatien intervals could be extended
to promote the use of such shallow greundwater by gr.owing plants and
reducing the water needs of the crops. While the corresponding values of cotton
were 15.58., 19.52 and 12.35% for the stated treatments. High pronounced value of 0.997 as a coefficient of determination fer each crop
was detected from the relation between water table depth in (m) as independent
variable (X) and the ET portion as % which supplied from water table as
dependent variable (Y). Regressien equations were: Maize: Y = 0.509-0.381 (X).
Cotton: Y = 0.605-0.504 (X).