Two field experiments were performed at the experimental
Farm Station of Sids Agricultural Research Station, Agricultural
Research Center during the two successive seasons 2003/2004 and
2004/2005 to study the effect of inorganic nitrogen fertilizer
applications (0, 25, 50 and 100% of recommended dose (75 kg N/fed)
for wheat plants in alluvial clay soil in Beni Suef Governomrate, and
seed inoculation with biofertilizer, namely, Rhizobacterin on both
grains and straw yields as well as N P K concentrations and uptake by
grains and/or straw. The experiment was laid out in a split plot design
in randomized complete blocks with four replicates.
Data indicated that both grain and straw yields significantly
responded to nitrogen fertilizer additions till the full recommended
nitrogen rate, i.e. 75 kg N/fed. Results also, showed that both grain
and straw yields significantly increased by seed inoculation with
Rhizobacterin inoculant, where the grain yield increases were 9.6 and
8.3% as compared with uninoculated in the two growing seasons,
respectively. The best grain and straw yields were obtained when
ammonium nitrate (33.5% N) was applied at 75% of recommended
rate, i.e. 56.25 kg N/fed in combination with Rhizobacterin
inoculation.
It was also found that increasing inorganic nitrogen fertilizer
increased both N and K concentrations and uptake in both grains and
straw, while P concentrations and uptake did not respond to inorganic
nitrogen fertilization. Also, biofertilizer application significantly
increased nitrogen concentration in grains and potassium
concentrations in grains and straw. Moreover, nitrogen and potassium
uptake in grains and/or straw were significantly affected by
Rhizobacterin inoculation. On the other hand nitrogen concentration
in straw as well as phosphorus concentration in grains or straw and its
uptake in straw were not affected by biofertilizer treatments. The
combination between inorganic nitrogen and Rhizobacterin
inoculation exert the same trend of the effect of biofertilization on
NPK concentration and uptake, where, in general the highest values
of NPK concentration and uptake were produced by wheat plants
fertilized with full recommended nitrogen rate (75 kg N/fed) or the
plants inoculated with bacterial Rhizobacterin inoculant and received
three fourth of recommended nitrogen rate, i.e. 56.25 kg/fed.
It could be concluded that 75% from recommended nitrogen
level combined with seed inoculation by Rhizobacterin satisfied the
demands of plant nutrition and the optimum yield production, avoided
excessive fertilizer applications and accordingly, reduced the costs of
chemical fertilizer applications and environmental pollutions.