A FIELD experiment was conducted in sandy soil at El-Sadat city Menoufiea Governorate, Egypt for two consuctive seasons (2012 and 2013) to investigate the effect of different sources and rates of potassium fertilizers on total yield and tuber quality of potato (Solanum tuberosum L.). Cv. Diamante grown on sandy soil. The experiment was conducted under drip irrigation system in split-split design with three replicates. Four sources of potassium were used, i.e. potassium sulphate (K2SO4), potassium chloride (KCl), potassium carbonate (K2CO3) and potassium hydroxide (KOH) with three rates, 80, 100 and 120 kgK2O/fed applied through irrigation water.
As regards to sources and rates of potassium fertilizers, results showed significant differences among the sources and rates of potassium fertilizers on total yield, tuber weight, tuber diameter, specific gravity and starch content of tuber. The data revealed that K2SO4 was the best among other sources. Data also showed that yield and quality of tuber increased with increasing potassium rates up to 120 kg K2O/fed. except KCl treatment. In both seasons, the highest tuber yield was 14.85 ton/fed. with potassium sulphate at 120 kg K2O/fed.