ABSTRACT
Afield trial including plant cane crop and 1st ratoon were conducted in
Mallawi Research Station-Minya Governorate (latitude of 28°10' N,
longitude of 30°75' E and altitude of 55 m above sea level) during
2017/2018 and 2018/2019 seasons to study the effect of dry-off periods (30
and 45 days before harvesting date) and potassium fertilizer “K" levels
(zero, 36 and 72 kg K2O/fed) on yield and quality of the some sugarcane
varieties (G.2003-47, G.2003-49, G.84-47 and G.2004-27), as compared
with the commercial variety GT54-9. A split split-plot design with three
replications was used. Drying-off periods were allocated in the main plots,
whereas K levels were distributed in the sub-plot, and sugarcane varieties
were randomly distributed in the sub–sub plot. The results showed that
raising dry-off period from 30 to 45 days led to a significant decrease in
cane yield reached 12% for the plant cane, corresponding to 10.92% in the
1st ratoon. Increasing K level from zero up to 72 kg K2O/fed produced an
increase in sugar yield by 24.29% and 20.11% in the plant cane and the 1st
ratoon, respectively. Sugar yield was negatively affected by the increase of
dry off days, which decreased by 13.6% in plant cane and 5.5% for the 1st
ratoon. However, sugar yield increased by raising K level up to 72 kg
K2O/fed by 34% and 30.34% in the plant cane and the 1st ratoon ,
respectively. Under the conditions of the current work, it could be
recommended that irrigating dry-off 30 days before harvesting date with 72
kg K2O/fed would attain the highest cane and sugar yields/fed.