Two field trials were carried out at Shandaweel Agricultural Research Station (Sohag Governorate) during 2003/2004 and 2004/2005 seasons. Each trail included 24 treatments represent the combination between three irrigation intervals (12, 16 and 20 days, i.e. a total number of 27, 20 and 16 irrigations), four potassium fertilizer levels (0.0, 25.0, 50.0 and 75.0 kg K2O/fed) and two sugarcane varieties viz. G.T.54-9 and Ph.8013. Treatments were arranged in a Split-Split Plot Design with three replicates. The main plots were assigned for irrigation treatments; sugarcane varieties were distributed in the sub plots and potassium fertilizer levels were randomly distributed in the sub-sub plots. The results showed that decreasing irrigation intervals from 20 to 12 days significantly increased stalk length, stalk diameter and cane yield/fed in both seasons. Applying irrigation water every 12 and/or 16 days attained significant increase in the number of millable cane/fed and sugar yield/fed. However, both of sucrose and sugar recovery percentages were negatively and significantly affected by increasing the periods between irrigations.
All the studied traits of sugarcane were positively and significantly influenced by increasing K level from 0.0 up to 75 kg K2O/fed.
The two sugarcane varieties differed significantly in their response to all studied characters. The commercial variety G.T.54-9 recorded higher values of stalk length and number of millable cane/fed, while the promising cane variety Ph.8013 had thicker stalks, higher sucrose and sugar recovery percentages, and sugar yields.
The present investigation showed that the planting sugarcane variety Ph.8013 irrigated every 12 or 16 days and fertilized with 75 kg K2O/fed is recommended to obtain the highest cane and sugar yields/fed