Two field experiments were carried out at Gemmeiza Agricultural Research
Station Farm during 1999 and 2000 seasons to study the influence of two potassium
fertilizer forms. i.e, potassium sulphate and potassium chloride at three different rates
o , 30 and 60 kg K₂0/fad on yield. yield components, NPK, and total carbohydrates
contents of onion and soybean. 1. Onion The obtained data indicated that fresh and dry weights of bulb and onion bulbs
yield / fad (as fresh and dry weights) was higher with K₂SO. than those treated with
KCI. Application of 30 and 60 kg K20/ fad significantly increased fresh and dry weight
(g) of bulb and, bulbs yield / fad. (as fresh and dry weights), compared to untreated
plants. On the other hand. increasing K fertilizer levels from 30 to 60 K20/ fad did not
affect bulbs yield / fad (as fresh and dry weights) as well as fresh and dry weights of
bulb. The NPK content and total carbohydrates in bulbs tended to increase with
application of KzS0₄• compared to KC!. Increasing applied K levels to 30 and 60 kg
K20 / fad led to increase P and K contents of bulbs whereas bulb N content did not
affect by incremental dose of K. 2. Soybean Yield components of soybean l.e, number of branches / plant number of
bods/plant. number of seeds/body. bod weight. seed yield/plant and 100- seed weight
ware not significantly affected by potassium source. Seed and straw yields of
soybean, fertilized with KzSO., was higher than those treated with KC!. Application of
30 and 60 kg KzO/ fad increased number of bods/plant. number of seeds/bod. seed
yield/plant. seed yield/ fad compared to control. The N. P and K contents were not significantly affected by potassium source or
levels. From the aforementioned results it can be concluded that for high yield
production of onion and soybean potassium fertilizer, must be applied at 60 for onion
and 30 for soybean Kg K20/ fad as potassium sulphate.