A pot experiment was conducted in a green house at Tishreen University in which bread
wheat (cv. Sham 6) was grown at different levels of potassium nutrition (K0=0, K1=25,
K2=50, K3=75, K4=100, K5=150) mg k/kg soil. The increase in potassium fertil
ization
rates led to a significant increase in the number of total tillers and fertile tillers on the
expense of non-fertile tillers. This was accompanied with no significant increase in
number of main stems spikes grains, while the tillers spikes of the first level of potassium
application (K1) was higher significantly compared to control treatment (K0). The same
treatment (K1) gave the best weight of grain on the main stems spikes and tillers. The
productivity of grain yield increased (but non-significantly) with increasing the level of
potassium fertilization. The highest yield value was obtained in K5 treatment which was
13933 kg /ha. This productivity constitutes a rate of increase 18% compared to the control
treatment (K0). The calculation of Agronomic Efficiency (AE) showed a high value of
(about 13 kg seeds/kg of K fertilizer added) in the K1 treatment, and thereafter, AE
gradually decreased with potassium fertilization to reach about 6 kg grain/kg K fertilizer
for K4 and K5 treatments (100 and 150 mg K/kg).
