Two field experiments were carried out at Gelbana district, Sahl El-Tina
(longitudes 32º 20' and 32º 33' E and latitudes 30º 57' and 31º 04' N), North Sinai
Governorate during the two seasons of 2011/2012 and 2012/2013 to study the
effect of the combined application of potassium fertilizer on some chemical
compositions, growth, yield and quality of sugar beet under saline soil. This
work included eighteen treatments represent the combinations among three
multi-germ sugar beet varieties viz. Gloria, Toro and Desperez poly N and six Kcombinations, which were:
1) The check treatment (without K application).
2) 3 cm3 l-1 as potassium silicate as foliar application,
3) 24 kg K2O fed-1 as potassium sulphate as soil application.
4) 48 kg K2O fed-1 as potassium sulphate as soil application.
5) 24 kg K2O fed-1 as potassium sulphate + 3 cm3 l-1 potassium silicate.
6) 48 kg K2O fed-1 as potassium sulphate + 3 cm3 l-1 potassium silicate.
A split plot design was used with three replications in both seasons, the main
plots were assigned to K-fertilization treatments, while sugar beet varieties were sown
randomly in the sub plots. The obtained results pointed out the following.
The applied potassium treatments either soil or foliar application alleviated
the adverse effect of soil salinity and significantly increased chlorophyll a, b and
carotenoides, root length, diameter and fresh weight/plant, sucrose%, sugar
extracted%, quality index as well as root and recoverable sugar yields/fed and
reduced Na root content, while increased K/Na ratio in root in comparison to the
control, in both seasons.
The application of K-fertilizer at 24 and/or 48 kg K2O fed-1 as soil side
dressing of K-sulphate, along with the foliar application of K-silicate at 3 cm3 l-1 were
more effective and significantly increased root yield (ton fed-1) by (8.19 and 10.24
%), and sugar yield by (8.83 and 13.85%) compared to the soil single application in
the 1st season and the 2nd one was the same trend. Supplying sugar beets by 48 kg
K2O fed-1 as form of K-sulphate, given as soil application, combined with foliar
application of 3 cm3 l-1, as K-silicate, significantly increased quality index and
sucrose% and reduced impurity index in both seasons compared to the soil single
application.
Gloria variety showed the superiority over the other tested ones and recorded
the highest values of chlorophyll a, b, proline, the thickest and heaviest roots/plant,
root and recoverable sugar yields/fed., sucrose%, sugar extraction% in both seasons
and K/Na ratio in the 2nd one. Fertilizing Gloria sugar beet variety with 48 kg K2O
fed-1 as K-sulphate added to the soil integrated with 3 cm3 l-1 of K-silicate sprayed on
beet foliage can be recommended to get the highest root yield/fed and sucrose% and
the lowest content of sodium in juice in Sahl El-Tina, North Sinai.