Response of Different Organic and Inorganic Sources of Nutrients on Growth and Yield of Kharif Onion (Allium cepa L.)

An experiment was conducted in Bihar Agricultural University, at Nalanda College of Horticulture, Noorsarai, during kharif season 2016, to assess the suitable source and optimum dose of organic fertilizer for kharif onion. The soil of the experimental plot was clay loam with 7.47 pH, 0.21 EC (dSm-1) and 0.62 % organic carbon, 262 kg, 14.60 kg and 142 kg ha-1 available N, P and K, respectively. The experiment comprised of seven treatments viz., T1-Chemical fertilizer (CF)120:60:40; T2-50 % NPK through CF+50 % N through FYM; T3-50 % N through FYM + 50 % N through VC; T4- 1/3rd of N each through FYM + VC + Neemcake; T5-50 % N through FYM + PSB + Azotobactor; T6-T3 + PSB + Azotobactor and T7-T4+PSB + Azotobactor. The experiment was conducted in randomized block design (RBD) with three replications. Results showed that plant height didn't show significant difference at 30 DAT, but as plant growth progressed, height of the onion plants differed significantly. At 60 DAT, T1 recorded highest plant (23.6 cm) which was significantly tall over T4 and T5. Although, at 90 DAT, T7 recorded maximum plant height (60.1 cm) plant followed by T6 (56.3 cm). No. of leaves differed significantly during early stage of crop growth but during later stage (90 DAT) it became non-significant. The number of leaves recorded more in T1 followed by T2, T6, T7 and T3 at 30 DAT. The similar trend of leaves number were also observed at 60 DAT. Equatorial diameter of bulb found highest in T1 (5.3 cm) followed by T2 (5.2 cm) which was significantly higher over T5 (4.4 cm), T7 (4.7 cm) and T4 (4.8 cm). Bulb yield differed significantly and found highest in T1 (364.79 q ha-1) which was at par with T2 (343.31 q ha-1), T6 (321.80 q ha-1) and T3 (307.25 q ha-1). There were found significant difference in gross return, net return and B : C ratio. Among all, T1 recorded highest gross return, net return and B : C ratio, followed by T2, T6, T3 and T7. Although, T2, and T6 recorded net return (Rs. 2.28, and 2.00 lacks ha-1) which was at par with T1 (Rs. 2.50 lack ha-1). On the basis result obtained T2 as 50 % NPK through chemical fertilizer + 50 % N through FYM can be adapted as sustainable onion production, as it performed bulb yield statistically at par with chemical fertilizer and also built-up appreciable amount of N (4.36 %), P (17.32 %) and K (3.86 %).