A field experiment was conducted during winter and rainy seasons of 2004-05 and 2005-06 at CCS HAU Rice Research Station, Kaul (Kaithal). The experiment consisted of combinations of six sources of organic manures viz.; no organic manure, FYM @ 15 t/ha, vermicompost N100, vermicompost N150, vermicompost N200 and vermicompost N250 and five fertilizer levels viz.; no chemical fertilizer, 25, 50, 75% recommended dose of nitrogen and 100% recommended dose of fertilizer (N-150, P2O5 60, ZnSO4-25 kg/ha). The studies revealed that grain yield of wheat increased significantly with each increasing dose of vermicompost up to N200 and N250, over control. Vermicompost N250, N200 and N150 were significantly superior to FYM and vermicompost N100. Nitrogen, phosphorus, potassium uptake increased with the increasing rates of vermicompost. Grain yield was also increased significantly with successive increase in nitrogen and fertilizer levels during both years. NPK uptake was found to be increased significantly with each increase in nitrogen and fertilizers level.
Increasing rates of vermicompost and fertilizers resulted into more availability of NPK in soil except K availability, which decreased significantly with increase in nitrogen and fertilizer levels. Higher doses of vermicompost resulted into more availability of nutrients in soil after the harvest of wheat crop than FYM.
Application of organic manure and fertilizers left residual effect on succeeding rice crop and it was observed that grain, straw and biological yields of rice were higher at higher levels of vermicompost as compared to its lower levels and FYM. Yield of rice increased significantly with each successive increase in nitrogen and fertilizer levels applied to wheat crop.