ASSESSING THE IMPACT OF POTASSIUM ON GROWTH, YIELD AND YIELD CONTRIBUTING TRAITS OF ONION (Allium cepa L.) IN COASTAL REGION OF BANGLADESH

Onion is a popular bulb crop in Bangladesh, valued not only as a spice but also a vegetable due to its nutritional value. The productivity of onion is hindered by several biotic and abiotic factors. Among the abiotic factors, one of the most crucial factors is salinity, which impacts negatively on the yield and quality of onion. A field study was carried out in the research field of the Department of Agriculture at Noakhali Science and Technology University, Bangladesh, during the period from November 2021 to January 2022, in order to identify the suitable dosage of potassium in coastal zones. The study was laid out in a Randomized Complete Block Design (RCBD) with three replications and three treatments, viz., T0 (no potassium), T1 (100 kg KCl ha-1), T2 (150 kg KCl ha-1), and T3 (200 kg KCl ha-1). Data collection included different growth and development stages such as plant height, number of leaves, length of leaves, bulb length, bulb diameter, bulb length, individual bulb weight, and fresh bulb production per hectare of onion. The maximum yield (12.81 t ha-1) and minimum yield (5.72 t ha-1) were recorded from T3 treatment (200 kg KCl ha⁻¹) and T0 treatment, respectively. The highest plant height (46.92 cm), number of leaves (10.03), leaf length (38.10 cm), bulb diameter (4.79 cm), bulb length (4.18 cm), and individual bulb weight (30.51 g) were observed from treatment T3 (200 kg KCl ha⁻¹), whereas the lowest data were obtained from treatment T0 (no potassium). Based on the results, T3 treatment, i.e., 200 kg KCl ha⁻¹, showed improved growth, yield, and yield-contributing characteristics of onion in coastal areas of Bangladesh.