Phosphorus Fertilizer Response to Onion (Allium cepa L.) Yield in Punjab, Pakistan

Background: Onion (Allium cepa L.) is one of the most essential plants in food with high nutritional value. However, application of right dose of phosphorous (P) is one of the constraints to the profitable onion yields in soils deficient in P.Methods: A systematic study to confirm the best dose of P was conducted for six years in the P deficient soil in farmers’ fields. Based on the findings obtained from 2008-09 to 2010-11, the research was undertaken to determine the effect of different phosphorus levels on the yield of onion in the Randomized Complete Block Design (RCBD) with a total of 114 replicates  in 2011-12 to 2012-13. Four treatments (160, 210, 260 and 310 kg P2O5 ha-1) were tested with N and K at 100 kg ha-1.Results: From the results of this investigation, the variance analysis showed the substantial P impact. The maximum marketable bulb yield (19.03 t ha-1) was obtained from the fertilizer combination NPK @ 100-310-100 kg ha-1 and was shown to be statistically higher than all other treatments.Conclusion: Nonetheless, the nutshell of the overall economic study is that poor farmers (Land holders >12 acres) may have options to select the NPK fertilizer combination @ 100:210:100 kg ha-1 and the average farmer may have options to select the NPK fertilizer combination @ 100:260:100 kg ha-1. But rich farmers (Land holders >25 acres) who can spend more money on fertilizers and are interested in the higher gross margin should follow the combination of NPK fertilizers @ 100:310:100 kg ha-1 to profitably increase their gross margin and maintain soil fertility for onion cultivation in Punjab, Pakistan.   Keywords: Onion; NPK; Plant nutrition; Phosphorus; Pungency