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.

Direct and Residual Effect of Integrated Nitrogen Management on Physico-Chemical Properties of Soil

Aim: To find out the direct and residual effect of integrated nitrogen management on physico-chemical properties of soil under rice – maize cropping system. Study Design: The experiment was laid out in randomized block design during kharif season and in split plot design during rabi crop. Place and Duration of Study: At Agricultural college farm, Bapatla during 2018-19 and 2019-20 in Kharif and rabi seasons. 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 one divided into two sub plots during rabi. Results: Applications of different treatments did not show any significant difference in physico-chemical properties of soil (pH and EC) at all the growth stages of rice and maize during both the years of study. Application of 75% RDN through green leaf manure + 25% RDN through inorganics (T5) to rice during kharif significantly improved organic carbon in both kharif and rabi seasons whereas different levels of fertilizers applied have not shown an significant influence on soil organic carbon content. Conclusion: Application of inorganic fertilizers, organic manures and their combination didn’t show marked difference on physico-chemical properties of soil like pH and EC. However substitution of 75% N through GLM in kharif season significantly improved OC content in soil during both kharif and rabi and organic carbon content was not influenced by the level of fertilizers from 50% RDF (S1) to100% RDF (S2).

Effect of integrated nitrogen management through organic and inorganic sources on the yield of rice (Oryza sativa L.) and status of soil fertility at harvest

The present investigation was conducted with the objective of utilizing locally available organic resources for substituting chemical fertilizer nitrogen partly and augmenting soil health. The experiment was carried out for the crop kharif rice (Oryza sativa L.) in coastal Karnataka with eleven treatments laid out in randomized block design with three replications. Vermicompost (VC), Poultry manure (PM) and Fish manure (FM) were used as organic nitrogen sources integrated with mineral nitrogen source of fertilizer urea at substitution ratios of 25, 50 and 100 percent. These treatments were compared with control and recommended dose of nitrogen. The results revealed that the substitution of 50 per cent of nitrogen through VC recorded significantly (P<0.05) higher plant height (92.27 cm), higher number of productive tillers (16.85 hill-1), higher grain yield (5434 kg ha-1) and straw yield ( 6817 kg ha-1) compared to control. The results of the soil sample analysis for soil fertility parameters indicated that the major nutrients were significantly (P<0.05) influenced by integrated nitrogen management. The available nitrogen (382.36 kg ha-1) and available potassium (143.7 kg ha-1) were significantly (P<0.05) higher in the treatment T4 where a recommended dose of nitrogen was substituted by 50 percent VC compared to control (294.05 kg ha-1 and 92.31 kg ha-1 respectively). However, the available soil phosphorus was significantly higher with treatment 50 per cent RDN substituted by PM (78.83 kg ha-1) as compared to control (43.93 kg ha-1). Thus, integrated resource management improved crop yield and post-harvest soil fertility.