Influence of nitrogen and potassium application on growth, yield and nutrient uptake by onion (Allium cepa)

A field experiment was conducted during spring season of 1996 and 1997 to study the influence of nitrogen and potassium on the onion (Allium cepa L.) cultivar Pusa Madhavi , at Indian Agricultural Research Insitute, New Delhi. The enhancement in dry weight of tops and bulbs was recorded up to 120 kg Nlha. Similarly, yield attributes like bulb diamefer and 100 bulb weight also improved up to 120 kg Nlha. The average increase in bulb yield over the control was 18.3 and 29.6% with the application of 60 and 120 kg Nlha respectively. The onion bulb yield significantly responded to nitrogen application up to 120 kglha. There was significant increase in nitrogen uptake up to 120 kg Nlha and in potassium uptake upJto 60 kg Nlha. Potassium application significantly increased the dry weight of tops and bulbs, bulb diameter, 100 bulb weight and bulb yield up to 40 kg K,O/ha. The potassium uptake enhanced up to 80 kg K,O/ha application during both the years and nitrogen uptake was affected significantly only in the second year.