Studies on split application of major nutrients through fertigation on growth, nutrient uptake and yield of onion (Allium cepa L.) in deep black soils of Karnataka

A field experiment was carried out at Irrigation Water Management Research Centre, Belavatagi, Navalgund, Dharwad during Rabi 2022-23 to study the “effect of split application of major nutrients through fertigation on growth, nutrient uptake and yield of onion (Allium cepa L.) deep black soils”. The design of experiment was Randomized Complete Block Design (RCBD) with 12 treatment combinations with different level viz. 100 per cent and 75 per cent of RDF applied through fertigation by use of completely water soluble fertilizers in different splits as compared to basal application of conventional fertilizer. Results of the experiment revealed that application of 25 per cent of RDF as basal and 75 per cent of recommended dose of N, P and K through fertigation recorded significantly higher yield (54.40 t ha^-1), net return (490870 ha^-1) and B: C ratio (3.20). Significantly higher uptake of N, P and K (162.78 kg ha^-1, 26.70 kg ha^-1 and 114.18 kg ha^-1 respectively.) and higher value for quality parameter like TSS, ascorbic acid, pyruvic acid and phenols (13.67 ° Brix, 12.58 mg 100 g^-1, 3.54 μmol g^-1 and 52.54 mg 100 g^-1, respectively) were recorded. Significantly higher available N, P and K status after harvest of crop was observed with 100 per cent of RDF applied by conventional fertilizer and method. Application of 25 per cent of RDF of NPK as basal and 75 per cent of RDF of NPK through fertigation results in decrease in physiological weight loss per cent, sprouting per cent and rotting per cent which helps in increase the keeping quality of onion bulb.