Direct and Residual Effect of Integrated Nitrogen Management on Productivity of Rice-maize Cropping System

Aim: To find out the direct and residual effect of application of organics, inorganics and their combination on yield and yield parameters of rice-maize cropping system. Study Design: The experiment was laid out in randomized block design during kharif season and split plot design during rabi. Place and duration of Study: At Agricultural college farm, Bapatla during 2018-19 and 2019-20. Methodology: After the preliminary layout, paddy was sown in kharif and maize was sown in rabi season. Vermicompost and green leaf manure were applied two weeks before sowing of paddy. Treatments applied for paddy were considered as main plots and each main plot was divided into two sub plots during rabi. Results: Higher grain yield, straw yield, drymatter production at tillering stage were recorded with the application of 50% RDN through vermicompost +50% RDN through inorganics (T9) during both the years of study. However, in succeeding maize, the kernel yield, straw yield and yield attributing characters (drymatter, cob length and test weight) were significantly highest in the treatment which received 75% RDN through green leaf manure+ 25% RDN through inorganic (T5). Among the fertilizer levels applied to maize, S2 (100% RDF) recorded significantly higher dry matter production over S1 (50% RDF) at all the stages of crop growth and during two years of experimentation. Conclusion: Substitution of 50 % N through vermicompost improved rice yield and yield attributes whereas substitution of 75% N through GLM have shown better residual effect in terms of improvement of yield and yield attributing characters of maize. Among the subplots application of 100% RDF significantly increased the yield when compared to 50% RDF.