Two field experiments were performed in a saline clay soil at EL-Hamoul
Center, Kafr EL-Sheikh Governorate during two successive seasons of 1998199 and
199912000 to study the effect of potassium fertilization levels and its application times
on growth, yield and yield components as well as quality of sugar beet (Beta vulgaris,
L.) cv Pelleno.The experiments were laid-out in a split plot design with four replicates.
Each experiment included sixty treatments comprising four K- fertilization levels (12,
24. 36 and 48 kg K20/fad) and four K-application times i.e.1I2, 213, 1/3 of every K-
level before the first irrigation and the remaining splits were applied before the second
irrigation. while. in the fourth treatment, potassium was splitted into three equal
portions applied before the first, second and third irrigations, respectively. Potassium
Obtained results can be summarized as follows:
Combined analysis of data collected after 120 and 150 days from planting in
the two seasons revealed that K-Ievels affected both fresh and dry weights of sugar
beet roots, foliage fresh weight, both root length and root diameter (em), foliage
length(em), leaf area index (LAI), crop growth rate (CGR) in g/day. Relevant results
showed, also, that K levels affected other growth variables under study such as
relevant growth rate (RGR) and net assimiltion rate (NAR),however, the differences
failed to reach the level of significance at 5%.
As far as limes of K- application was concerned, combined analysis of data
for the two seasons revealed that most of growth characters were not significantly
affected by this factor . However, potassium fertilizer levels splitted into two equal
portions or into two thirds and one third applied before the first and second irrigations,
respectively, seemed to be ,in general, more favourable under conditions of the
current study.
Likwise, the interactions between potassium fertilization levels and potassium
application times did not induce clear effects on the averages of most characters
except leaf area index (LAI) since the highest means were recorded due 10 K-Ievel of
36 or 48 kg K20lfad applied as 2/3+ 1/3 or 112+112 before the first and second
irrigations, respectively.
With regard 10 both root and top yields(Vfad) as well as sugar yield (Ufad), it
was noted that incremental doses of K-application favoured these variables upto 36
kg K20/fad .Increasing K20 level upto 48 kg K20 /fad did not exhibit signficant
increases as far as that these characters were concemed since higher concentrations
of Na" could replace K+, in part, for uptake by sugar beet plants under such soil
circumstances of the present study.
It is worthy to note, also, that neither levels of K-fertilization nor times of it,
application affected significantly total soluble solids (TSS), sucrose % and apparent
. purity % in any of the two seasons and combined analysis ,as well.