IMPACT OF CULTIVARS, BIO-FERTILIZER AND N FERTILIZER LEVELS ON NITROGEN USE EFFICIENCY (NUE) AND YIELD OF WHEAT (Triticum aestivum L.)

Two field experiments were carried out at the Experimental Farm (Ghazala
Village), Faculty of Agriculture, Zagazig University, Sharkia Governorate, Egypt, during
2015/2016 and 2016/2017 seasons to study the influence of the bio-fertilizer Azotobacter
(without and with inoculation) and four N levels (0, 40, 80 and 120 kg N/fad.) on nitrogen
use efficiency (NUE), yield and its attributes of two bread wheat cultivars (Gemmeiza11
and Misr2). Results of combined analysis revealed that Misr2 cultivar produced the highest
number of spikes per square meter, grain and biological yields compared to Gemmeiza11 which
was superior in plant height, spike length, spike grain weight, thousand grain weight and harvest
index, as well it was higher in NUE. Inoculating wheat grains with Azotobacter chroococcun (in
commercial form Biogein) before sowing significantly increased studied traits i.e. Plant height,
spike length, spike number/m2, grain weight/spike, 1000-grain weight, grain and biological
yields/fad., and harvest index, but in contrary NUE decreased by Azotobacter inoculation
during the two seasons and their combined analysis. Results of combined analysis also
indicated that increasing N application level up to 120 kg N/fad., significantly increased each of
plant height, spike length, spike number/m2, grain weight/ spike, grain and biological yields/
fad., and decreased NUE that responded to N addition up to 80 kg N/fad. Significant
interactions between the studied factors indicated that the addition of Azotobacter increased
the response of wheat cultivars to the increase of N level particularly. According to the
results of the interactions between cultivars and Azotobacter, cultivars and N-fertilizer levels
and between Azotobacter and N levels, wheat cultivar Misr2 should be fertilized with
Azotobacter and 120 kg N/fad., to produce the highest yield. Moreover, the results showed
the significant interaction effect between bio and N fertilizer levels on NUE where the
efficiency of N use was higher with Azotobacter inoculation and 80 kg N/fad., in
comparison to control and 120 kg N/fad.