2.Materials and methods
2.1. Plant materials and experimental procedure
During 2013 and 2014 growing seasons, 20-uniform tissue culture-regenerated palms of 5 years old of ‘Barhee’ date palm cultivar were selected in a newly established orchard at the experimental station of the Faculty of Meteorology, Environment and Arid land Agriculture at Hada Al-Sham (110 km north east of Jeddah N, E), KSA. The soil of the experimental site is classified as sandy loam calcareous soil with an average field capacity of 22%. The average soil bulk density is 1.54gcm−3