Sour orange (Citrus aurantium L.) seedlings were sprayed three times a
season with four levels of urea (45 % N) (2.5, 5.0, 7.5 and 10.0 g/L) and two
levels of ascorbic acid (150 and 300 g/L), each alone or in combinations.
Meanwhile the seedlings
of control treatment sprayed with distilled water
during 2010 growing season, twenty days intervals between each spray and
another. Results obtained at the middle of October of the same season,
indicated that the foliar spray with urea at the concentrations of 5.0, 7.5 and
10.0 g/L significantly increased leaves N and chlorophyll concentrations, leaves
number, seedling leaves area, seedlings height, main stem diameter and leaves
fresh and dry weight, especially at the foliar spray with 10.0 g/L. The means of
these parameters were 3.19%, 66.80 SPAD, 146.66 leaves/seedling, 3700.00
Cm², 83.66 Cm, 4.50 mm, 4.70 g, 1.53 g, respectively. Meanwhile ascorbic acid
spray at two concentrations unsignificantly affected all parameters, except
leaves chlorophyll content, leaves number and seedling leaves area. Most
treatments of combinations spray with urea and ascorbic acid significantly
affected all studied parameters, especially the treatment of foliar spray of urea
and ascorbic acid at a concentration of 10.0 g/L and 300 mg/ L, which gave the
highest means of leaves N concentration, leaves number, seedling leaves area
and leaves fresh and dry weights, and it unsignificantly differs from the
treatments which gave the highest means of seedlings height, main stem
diameter and percentage of leaves dry matter weight .
Peach (Prunus persica Batsch) transplants cv. Dixired were sprayed three
times a season with three levels of urea (45% N) (2.5, 5.0 and 7.5 gm/ L), and
two levels of iron (10 and 20 mg Fe/ L) using chelated iron Fe-EDDHA
(6%iron), each alone or in
combination. Meanwhile the control transplants
sprayed with distilled water during 2006 and 2007 growing seasons, twenty
days intervals between each spray and another, the first spray is done at the
first week of May in both seasons. Results indicated that all spray treatments
with urea and iron each alone or with each other significantly increased leaves
N, K, Fe, chlorophyll and carbohydrate concentration, transplant leaves area,
shoots number, transplants height, main stem diameter and vegetative and root
dry weight. While leaves P concentration, significantly decreased with the foliar
spray with two concentrations of iron alone, or in combination with all
concentrations of urea. The best treatment was 7.5 gm urea/ L + 20 mg Fe/ L.,
which gave the highest means of all studied parameters, except leaves P
concentration, which were the highest mean of it was in the control treatment
at both seasons.
