EFFECT OF NITROGEN AND ITS APPLICATION METHOD ON THE GROWTH AND YIELD OF SUMMER ONION

Abstract

A field experiment was conducted at Bangladesh Agrteultttral Research Institute (BARE), Gazipur from March 2005 to July 2005 to determine the optimum dose and time of application nitrogen (br summer onion in Chhiata series of Grey Terrace Soil. Six levels of nitrogen At,. A, A2 A3A.1 and A i,e.0,50, 100.150.200 and 250 kg ha', respectively and three application methods viz, basal. ¼ basal V2 at 20 DAT and 1/3 basal + 1/3 at 20 DAT - 113 at 40 DAT were used. A significant improvement in different growth parameters, yield attributes, bulb yield as well as nutrient uptake was observed in response to different application methods and sources of nitrogen. Among the methods, three-splits recorded relatively higher plant height, leaf length, bulb diameter, bulb number, weight of single bulb and uptake of nitrogen, phosphorus, potassium and sulphur. The growth and yield of summer onion increased with increasing levels of nitrogen and application method. Application of nitrogen at 200 kg ha' produced the highest bulb yield (14.68 t lia), but the highest level of nitrogen (250 kg ha'') should statistically significant decrease in the yield of summer onion. The lowest bulb yield (8.29 t ha 4 ) was obtained in control (0 kg N ha''). The highest bulb yield (12.83 t ha") was obtained from three split application of nitrogen and the lowest bulb yield (11.65 t ha'') was obtained horn application of basal closes of nitrogen. The combined ei'ket of different levels of nitrogen and its application sequence statistically significant. The combination of three split application of 200 kg N ha" (A4 B2) gave the highest bulb yield (15.46 1 Iia) and the lowest bulb yield (8.25 t ha'5 was obtained from control (A080 ). 'lh,'ee split application of 200 kg N ha" (A 4 B2) may be considered to be optimum for getting higher yield as well as higher net profit (Tk 1,48,460.00. ha") of summer onion at Chhiata series ol'Grey Terrace Soil of Bangladesh.