Effect of Level and Timing of Potassium Application on Growth and Yield of Rabi Onion and Residual Soil Fertility in Light Textured Soil

Abstract

To study the Effect of level and timing of potassium application on growth and yield of rabi onion and residual soil fertility in light textured soil. The study area was field experiments were conducted at CRC of Sardar Vallabhbhai Patel University of Agriculture and technology, Meerut during rabi season of 2021 and 2022. Soil of experimental site was low in organic carbon, available nitrogen, medium in available phosphorus and potassium with slightly alkaline pH. Eleven treatments were applied with three replications in randomized block design and onion cultivar Agrifound Light Red was grown. The half dose of nitrogen and full dose of P and S was applied at the time of transplanting while remaining dose of nitrogen was applied after 30 DAT. Potassium was applied as basal and in two and three splits as per the treatments. Observations were recorded on the different growth parameters and yield attributing characters while soil and plant nutrient status were analyzed after crop harvesting in every year. Data were subjected to statistical analysis on which basis the treatments effect were explained. The results reported that all growth parameters and yield attributing characters of onion were higher with the application of 100% K through polyhalite than MOP as basal application. The maximum yield was recorded under T11 (RDF NP+100% K by polyhalite) followed by T9 (NPS + K75-50% basal + 50% at bulb formation stage). The crop quality in terms of nutrient content and uptake also improved with the application 150% of recommended potassium through MOP or 100% recommended through polyhalite in combination with N and P. The potassium use efficiency and recovery per cent was also higher under T11 (RDF NP+100% K by polyhalite) due to additional supply of sulphur, calcium and magnesium. The availability of nutrients in soil either improved or maintained by the balanced fertilization. Higher and quality yield of onion bulb ultimately increased the net return and B:C ratio which achieved by the application of potassium through polyhalite, followed by 150% of recommended dose through MOP. On the basis of present study, it can be concluded that potassium application is very important aspect in onion production and a multinutrient carrier like polyhalite can be a better option as compared to MOP.