Effect of Potassium Fertilizer Sources and Rates on Bulb Yield and Shelf Life of Onion Varieties in Jimma

Abstract

Onions are crucial vegetable and cash crops in Ethiopia, but farmers struggle to optimize bulb yield and shelf life due to unbalanced fertilizer use. Nitrogen and phosphorus are commonly used, but potassium (K) is also important. This study evaluated the effect of potassium fertilizer sources and rates on bulb yield and shelf life of onion varieties in Jimma during 2023/2024. Two varieties (Bombay Red and Nafis), two potassium sources (potassium nitrate and potassium chloride), and four application rates (0, 60, 120, 180 kg/ha) were studied using 2*2*4 factorial arranged in Randomized Complete Block Design (RCBD) with three replications. Data on growth, yield, and shelf life were analyzed using SAS. Results showed significant the main effects of variety, potassium source, and rate on most parameters. Nafis had a taller plant height (53.99cm) and better shelf life (a rotting number for Nafis is approximately 23.21% less than that of Bombay Red), whereas, Bombay Red had a higher yield (24.98 tons/ha. Potassium nitrate was more effective than potassium chloride on plant height (54.06cm), sheath diameter (12.73mm), total bulb yield (24.47 ton/ha),