Field experiment was conducted to evaluate the use efficiency of
nitrogen and zinc on growth and yield parameters of wheat plant. This
work was carried out in clayey textured soil at Show village, Abnob
district, Assiut Governorate, during the year, 2011-2012 season. A
randomized complete block design experiment with three replicates
was carried out using wheat (Var.Sids 8) as plant indicator. The
experiment included 25 treatments i.e., five nitrogen application rates
(0, 50, 75, 100 and 125 kg N fed-1) as urea which was in two equal
doses(after 25 and 40 days of sowing) at the time of irrigation. Also,
five zinc application rates (0, 5, 10, 15 and 20 kg Zn fed-1) as ZnSO4 by
broadcasting in powder form mixed with the soil at seedbed
preparation.
Application of N at rates of 50, 75, 100 and 125 mg kg-1 resulted
in percentage increases in yield of grains equivalent to 258, 223, 212
and 263 %, respectively as compared with the corresponding values of
the control plants (0.0 level N). In case of straw, the corresponding
increases were 227, 252, 250 and 199 %, respectively. The results show
that application of Zn up to 10 mg kg-1 soil has a positive effect on
grain yield of wheat. Addition of 5 and 10 mg Zn kg-1 soil caused
significant (0.05) increases in yield; the increases were 51 and 26 %,
respectively over the control treatments.
Concerning the interaction between nitrogen and zinc application,
data showed that the 1000 grain weight values increased by using
different levels of N and Zn compared with the control, where the 50 kg
N fed-1 with 10 kg Zn fed-1 caused significant increases in the yield and
the best treatment of the 1000 grain weight grams. On the other side,
increasing Zn application over 10 kg fed-1 caused pronounced and
significant decreases in weight yield. The interaction effect of N and
Zn treatment on grains and straw attained its highest values conceded,
with of 125 kg N and 5 kg Zn fed-1 and 75 kg N fed-1 + 5 kg Zn fed-1,
respectively. The results showed that the rate of 50 kg N/fed, gave the
best Physiological efficiency (PE) compared with other treatments (i.e.,
75, 100 and 125 kg N/fed). While, the values were increased as the
application rates of Zn increased (i.e. 5 and 10 kg zinc/fed), and then
decreased with increasing Zn application (i.e. 15 and 20 kg Zn /fed).
The best physiological efficiency (PE) accompanied with the rate of 10
kg zinc/fed.