Integrated effect of vermicompost and nitrogen fertilizers on soil nutrient status and yield of onion-radish cropping system

A field experiment was conducted on a sandy loam soil during kharif (onion) and rabi (radish) seasons of 2007–08 with a view to study the effect of integrated use of vermicompost (0, 5 and 10 t/ha) and nitrogen fertilizers (0, 60, 90 and 120 kg N/ha) on soil nutrient status and yield of onion-radish cropping system. Among the different combinations, application of 10 t vermicompost/ha+120 kg N/ha (V₂N₃) recorded significantly highest fresh bulb yields (24.45 t/ha) at harvest. However, the bulb yield at V₂N₃ was on par with the yield obtained at V₂N₂ (23.43 t/ha). The radish crop grown during rabi responded favourably to the residual and cumulative treatments and the highest root yield of 23.43 t/ha was recorded in cumulative treatments at V₂N₃ level. The addition of vermicompost (a. 10 t/ha alongwith nitrogen @ 120 kg/ha has recorded the highest available N (228.9 kg/ha), P₂O₅ (48.39 kg/ha) and K₂O (322.9 kg/ha) in soil after harvest of onion. The available N (243.7 kg/ha), P₂O_s (52.80 kg/ha) and K₂O (288.7 kg/ha) contents in soil at the end of onion-radish cropping system showed significantly highest values at V₂N₃ level under cumulative treatments. Application of 10 t vermicompost/ha alongwith 120 kg N/ha (V₂N₃) to preceeding onion crop and 75% recommended dose of NPK fertilizers to succeeding radish crop showed highest total nitrogen content in soil at the end of onion-radish cropping sequence. However, application of different levels of nitrogen and vermicompost did not show any significant effect on total P and K contents in soil.