Abstract

                                A field experiment was conducted at Agriculture College and Research Institute, Killikulam, Tamil Nadu during rabi season of 2017-18 to determine the effect of zinc and boron along with soil test crop response (STCR) application of N, P and K for achieving better yield and quality of onion crop. The experiment was laid out in a randomized block design with three replications. The experiment consisted of eight treatments viz., T1 - Soil Test Crop Response (STCR) as 106:97:54 kg of NPK ha-1, T2 - STCR (106:97:54 kg of NPK ha-1) + ZnSO4 @ 25 kg ha-1, T3 - STCR (106:97:54 kg of NPK ha-1) + ZnSO4 @ 0.5% foliar spray, T4 - STCR (106:97:54 kg of NPK ha-1) + ZnSO4 @ 25 kg ha-1 + 0.5% foliar spray, T5 - STCR (106:97:54 kg of NPK ha-1) + borax @ 10 kg ha-1, T6 - STCR (106:97:54 kg of NPK ha-1) + borax @ 0.5% foliar spray, T7 - STCR (106:97:54 kg of NPK ha-1) + borax @ 10 kg ha-1 + 0.5% foliar spray, T8 – control. The results showed that yield parameters like bulb lets clump-1 (6.4), polar diameter (3.35 cm), equatorial diameter (2.98 cm), weight of bulb (85.2g) and bulb yield (16.85 t ha-1) and bulb qualities such as total soluble solids (15.7 oBrix), ascorbic acid content (13.95 mg 100g-1), protein (8.46%) and pyruvic acid content (4.82 μmol g-1) was better in application of STCR (106:97:54 kg of NPK ha-1) + ZnSO4 @ 25 kg ha-1 with 0.5% foliar spray. This treatment recorded the highest net income (Rs.254243 ha-1) and B:C ratio (4.07).

Key words : Onion, STCR, Zinc and Boron, Yield and bulb quality.