Abstract

A field experiment was conducted to evaluate the effects of organic and inorganic sources of nitrogen on the post-harvest fertility status and yield of BRRI Dhan 29. Incorporation of recommended dose of nitrogen (RDN) @ 150 kg/ha from cowdung as organic nitrogen source and urea as inorganic nitrogen source along with a control was performed under RCBD design. All the treatments under study also received P20 K65 S18 Zn1.3 through inorganic sources of fertilizers. The grain and straw yields as well as the yield contributing characteristics like plant height, number of tillers/hill, number of effective tillers/hill, panicle length, number of grains/panicle and number of filled grains/panicle were significantly influenced by the different treatments. Significantly highest grain (5.89 t/ha) and straw (6.14 t/ha) yields were recorded from the treatment T1 where 100% RDN provided from urea that was closely followed by the treatment T6 (80% RDN from urea+ 20% RDN from cowdung). Analyses of post-harvest soil fertility status revealed that the treatments amended with cowdung as organic source of nitrogen positively influenced the bulk density, porosity, organic carbon, total N, available P, exchangeable K and available S contents of soil, while all the treatments slightly decreased the bulk density and soil pH. Considering the results, treatment T6 (80% RDN from urea+20% RDN from cowdung) may be suggested for adequate substitute in reducing the chemical nitrogen usage for sustained boro rice cultivation.