BULB YIELD OF SUMMER ONION (BARI PIAZ-5) AS INFLUENCED BY THE APPLICATION OF NITROGEN AND POTASSIUM

Abstract

Lower average yield of onion bulb is the main bottleneck for getting self-sufficiency on onion in Bangladesh. Application of nitrogen and potassium nutrients may improve the yield contributing traits of onion. From the perspective, the experiment was carried out in the research field of Sher-e-Bangla Agricultural University (SAU), Dhaka-1207 during the period from June to September, 2021. The variety, BARI Piaj 5 (Summer variety) was used as test crop under present study. The experiment consisted of two factors viz., factor-A (Nitrogen levels-4): N ii 0 = 0 kg ha = 50 kg ha -1 , N 2 = 75 kg ha -1 and N 3 = 100 kg ha -1 and factor-B (Potassium levels-3): K = 0 kg ha -1 , K 1 = 50 kg ha -1 and K 2 = 100 kg ha -1 . The experiment was conducted by following factorial RCBD (Randomized Complete Block Design) design with three (3) replications. Result revealed that, a gradual increasing trend was found with the increasing of nitrogen (N) levels for most of the parameters studied except nonmarketable

yield (t ha -1 ) and small size bulb (< 30 mm) of onion. Similar trend was also found in case of potassium (K) application. The application of N at the rate of 100 kg ha -1 exhibited the best one dose for yield and yield contributing traits of summer onion which was statistically similar to 75 kg ha -1 . When the onion crop is treated with 100 kg K ha -1 showed the best performance for most of the parameters studied. The highest yield and marketable yield of onion bulb (17.876 t ha and 16.616 t ha -1 , respectively) was found from N 3 K treatment combination which was statistically similar to N 2 K 2 (17.369 t ha -1 2 and 16.134 t ha -1 -1 , respectively) treatment combination while the lowest (9.352 t ha -1 and 5.885 t ha -1 , respectively) was found in N 0 K treatment combination. In case of post-harvest soil properties, the highest total nitrogen and exchangeable potassium were found from N 0 3 K (0.083 % and 0.491 meq/100 g soil, respectively) treatment combination over control. Different yield contributing traits of summer onion and also the soil properties were strongly correlated with each other. Application of nitrogen at the rate of 75 and 100 kg ha 2

along with potassium at the rate of 100 kg ha -1 gave the better bulb yield merit (182.55 % and 174.16 %, respectively) over control. Finally, on the basis of monetary advantages it may be concluded that application of nitrogen @ 75 kg ha along with potassium @ 100 kg ha -1 is best for summer onion production.