An experiment was carried out at the experimental of farm of Rice Research
and Training Center, Sakha (RRTC) in 1997, and 1998 rice growing seasons on the
susceptible rice cultivar Giza 176. A split plot design was carried out to study the
effect of nitrogen fertilizer rates either alone or in combination with P, K and Zn on rice
blast disease. Three nitrogen rates were used as main treatments i.e. 0,40 and 80 Kg
N/fed. While eight treatments as combination between P, K and Zn were used as sub
treatments. The obtained incombination results from both seasons 1997 and 1998
showed that severity of blast infection on leaves and Panicles increased by increasing
nitrogen rates. The blast infection decreased under high nitrogen level by adding
phosphorous alone or incombination with potassium and zinc, as compared with high
nitrogen level alone. The lowest blast infection either on leaves or panicles as well as
the highest grain yield were obtained under the balance of P, K and Zn (15-24-10 Kg I
fed.) with the recommended nitrogen rate (40KgN/fed). Total nitrogen content significantly increased in plant tissues from 1.16 to 1.55 %
as the increasing of nitrogen doses from zero up to 80 Kg N Ifed. with no application
of P, K and Zn. A little increasing was observed between P content in plant tissues
come from plants grown in treated plots by Phosphorus application than the other
untreated plots. Plant height, number of tillers I hill, number of leaves I hill and leaf
area increased by the increasing nitrogen rates from zero up to 80 kg I fed. The
largest numbers for each character were obtained under 15, 24 and 10 Kg Ifed. For
(P, K and Zn) respectively, compared with the same treatment of nitrogen rate.