Potassium (K) is a critical element for date palm production especially under stress conditions. During 2011 and 2012 seasons, two methods of K
fertilization (K2SO4, 52% K2O) at different rates were evaluated on ‘Seweda’ date palm cultivar. The first method was soil broadcast (SB) of 2, 3 and
4 kg/palm in 3 equal doses (February, April and May). While in the second method, half of these amounts were applied as SB and the other half as
foliar spray (FS) in 10 equal doses during growing season. The results showed no significant effect of K fertilization on either bunch weight or yield
as the mean of two seasons. However, in 2012, the highest bunch weight and yield was at the 2 kg SB + 2 kg FS treatment while, the lowest values
were at the 2 kg SB treatment. The highest rutab % obtained from the 2 kg SB treatment. Both fruit and flesh weight at the bisir stage were higher at
the high rates of K applied as SB + FS than SB. Also, K concentration of leaves was higher in SB + FS than SB. K had no clear effect on chlorophylls,
however, the highest Chl a/Chl b ratio was at the 2 kg SB + 2 kg FS treatment. Most of physical and biochemical characteristics of fruit showed unclear
response to K fertilization. In fruit, N concentration was lower at the high rates of K applied as SB + FS than SB. At the same K fertilization rate,
both N and K concentration in the soil were higher at SB than SB + FS treatments. Potassium fertilization especially at 4 kg K2SO4/palm/year (2 kg
SB + 2 kg FS) is recommended for ‘Seweda’ dates.