Effect of Inorganic Fertilizers (NPK) with Organic Sources (Biomix and Humic Acid) on the Bulb Quality and Storage Quality of Onions (Allium cepa L.)

An investigation entitled "Effect of different levels of fertilizers with organic sources on growth, yield and quality of onion (Allium cepa L.)" was undertaken at the experimental farm, Department of Horticulture, VNMKV, Parbhani, Maharashtra, in the late Kharif season of 2020–21 and 2021–22. The present investigation was laid out in a factorial randomized block design (FRBD) with three different levels of recommended dose of fertilizers (RDF): F1: RDF 80% (80:40:40 NPK kg/ha), F2: RDF 100% (100:50:50 NPK kg/ha) and F3: RDF 120% (120:60:60 NPK kg/ha) with six levels of organic sources, namely, S0 : Control, S1 : Biomix 10 kg/ha, S2 : Biomix 12.5 kg/ha, S3 : Biomix 15 kg/ha, S4 : Humic acid 05 kg/ha and S5 : Humic acid 10 kg/ha comprising eighteen treatments and replicated thrice. The aim of this work is to study the effect of different levels of RDF and organic sources on the bulb quality and storage quality of onions (Allium cepa L.). The onion bulb produced under 120% RDF has recorded the higher mean values of the quality parameters, viz., chlorophyll content (63.44 SPAD value), ascorbic acid content (11.71 mg/100 g), total soluble solids (12.23%), reducing sugar (2.33%), non-reducing sugar (5.27%) and total sugar (7.60%). Among the organic sources, humic acid at 10 kg/ha had the highest mean chlorophyll content (59.66 SPAD value), total soluble solids (11.91%), reducing sugar (2.29%), non-reducing sugar (5.03%), and total sugar (7.32%), with the exception of ascorbic acid (10.89 mg/100 g), which was highest at biomix 15 kg/ha. In five months of storage studies, the mean minimum physiological loss in weight (18.47%) at ambient storage was observed under 80:40:40 NPK kg/ha, and the maximum total soluble solids (%) were recorded at 120:60:60 NPK kg/ha. During a five-month storage study, the mean minimum PLW (18.55%) at ambient storage was recorded under biomix at 15 kg/ha. The mean maximum total soluble solids were found after humic acid treatment (10 kg/ha) in the fifth month of storage.