Two field experiments were conducted at Sakha Agricultural Research Station, through the two growing seasons (1999 and 2000) In the Middle Delta region,
to study the effect of three irrigation depths and some rice cultivars on protein content
in rice grains, percentage and uptake of N, P and K in rice straw and grains. The protein content in rice grains, the percentage and uptake of N, P and K
in rice grains and straw were increased with increasing Irrigation depth up to 7.5 em.,
but this increase was not significant. The mean values of percentage and uptake of N,
P and K in rice grains can be arranged as follows: N > P > K. while in rice straw can
be arranged as follows: K> N > P. Data also indicated that the mean values of N, P and K in rice straw were
higher under rice cultivar Sakha 101 than those obtained under the other two rice
cultivars, Giza 171 and Giza 177. On basis of these mean values of the planted cultivars • they can be
arranged as follows: Sakha 101 > Giza 171 > Giza 177 rice cultivars. While the mean
value of N, P and K uptake in rice grains of studied cultivars can be arranged as
follows: Sakha 101 > Giza 177 > Giza 171. Increasing the amount of irrigation water
applied led to an increase in protein content in rice grains and N, P and K percentage
and uptake of both rice grains and straw.