FOLIAR UREA AS A SUPPLEMENT OF SOIL NITROGEN APPLICATION FOR WHEAT GROWN UNDER DIFFERENT PLANTING METHODS

Foliar urea application is one of the nitrogen (N) application methods in cereal crops.
Yield and yield components may be affected by foliar urea application. A field experiment was
conducted at Agriculture Research Center Experimental Station, Giza Governorate, Egypt, to evaluate
the effect of soil and foliar application of urea applied in different concentrations and at different
stages on yield, yield components, nutrient uptake and grain protein content of wheat (Triticum
aestivum L). The experiment was laid out in split plot design with three replications. Recommended
dose of N fertilizer (90 kg N fad.-1) as urea was added at 3 stages (two leaves, tillering and booting
stage) as soil application, with flat and/or terrace method of sowing. Soil application of 60 kg N fad.-1
as urea was added at 3 stages (two leaves, tillering and booting stage), and 10 kg N as 2.5% urea foliar
application at (tillering and booting stage) with flat and/or terrace sowing method. 30 kg N fad.-1 soil
application as urea added at 3 stages (at two leaves, tillering and booting stage), and 10 kg N as 2.5%
urea foliar application at (tillering and booting stage) with flat and/or terrace sowing method. The
results revealed that application of N at rate of 60 kg N fad.-1 as urea combined with foliar urea
produced relative increase since it recorded 4.29%, 2.62%, 13.35%, 1.69%, 12.92%, 15.85%, 14.17%
and 1.83% for plant height, spike length, tillers, 1000 grains as well as, straw, grain, biological yields
and harvest index, respectively compared with the recommended dose of N as soil application (90 kg
N Soil applied). Application of nitrogen at different levels as soil application or combined with foliar
urea spray in terrace planting increased nutrients concentrations and its uptake in straw and grains of
wheat plants compared with the flat planting. While, the highest values of N, P, K, Fe, Mn and Zn in
straw and grains of wheat plants were obtained in plots received 60 kg N fad.-1 + foliar urea spray
compared with all other treatments. The results indicated that nitrogen use efficiency (NUE) decreased
with increasing N rate as soil application. Maximum nitrogen use efficiency (50.61%) was recorded at
application of 60 kg N fad.-1, as soil application along with 2.5% urea as foliar application and
minimum of it (39.4%) was recorded at 90 kg N fad.-1, as soil application along with 2.5% urea as
foliar application. The plants which fertilized with the rate of 60 kg fad.-1 + foliar urea spray with
terrace planting gave the best protein content in wheat grains (11.43%). The residual nitrogen in the
soil was significantly increased with increasing application of nitrogen fertilizer. It was noted that
plots that received 90, 60 and 30 kg N fad.-1 significantly retained more nitrogen and was higher by
42.3, 35.9 and 31.1%, respectively than the control treatment.