Effect of nutrient management on soil nutrient status, its uptake and yield of rabi onion

The fertilizer treatment 110: 40: 60: 40 kg NPKS + 7.5 t FYM + 2.5 t PM + 2.5 t VC+ biofertilizers (Azospirillum, phosphobacteria 5 kg each) ha⁻¹ recorded higher potential for total bulb yield (54.63 t ha⁻¹) as compared to RDF (33.00 t ha⁻¹). The soil available N, P and K contents in the soil after harvest significantly increased due to the combined application of organic manures, inorganic fertilizers and biofertilizers in integrated manner. The residual soil fertility in respect to organic carbon (0.60%), available sulphur (10.30 mg kg⁻¹), boron (0.58 mg kg⁻¹) and zinc (0.76 mg kg⁻¹) was also significantly improved by various treatments and was found highest in the treatment receiving 110: 40: 60: 40 kg NPKS + 7.5 t FYM + 2.5 t PM + 2.5 t VC + biofertilizers (Azospirillum, phosphobacteria 5 kg ha each). Total nutrient uptake of nitrogen (103.40 kg ha⁻¹), phosphorus (38.50 kg ha⁻¹), potassium (96.48 kg ha⁻¹), sulphur (29.22 kg ha⁻¹), boron (162.78 g ha⁻¹) and zinc (385.50 g ha⁻¹) by onion crop were recorded under this treatment which was significantly highest. The results indicated that judicious use of organic manures, inorganic fertilizers and biofertilizers as integrated nutrient management system was found to be useful for enhancing the yield, soil fertility and uptake of various nutrients in rabi onion.