Effect of seaweed (Kappaphycus alvarezii) extract on rainfed aerobic rice (Oryza sativa L.)

Rice is grown throughout the year in India, in a variety of agro-climatic conditions, and it is grown on 43.39 million hectares with a production of 159.20 MT with an average productivity of 3623 kg/ha. Aerobically produced rice may be an option for farmers on rainfed areas where rainfall is not sufficient or availability of water is rare and expensive too for flooded rice production but enough for cultivation of upland rice. The field experiment took place at Crop Research Farm, Department of Agronomy, Sam Higginbottom University of Agriculture Technology and Sciences, Prayagraj, Uttar Pradesh, India, during the kharif season of 2020. The experiment was done by using Randomized Block Design with three replications. The findings of the experiments revealed a considerable rise in the growth parameter viz., plant height (46.0 cm), total tillers/m2 (564.3), plant dry matter accumulation (1938.0 g/m2), leaf area index (19.07) and crop growth rate (49.47 g/m2/day) and yield attributing parameters viz., effective tillers/m2 (362.3), weight of panicle/m2 (856.9), number of filled grain/panicle (115.7), grain yield ( 4.7 t/ha), test weight (28.9 g), straw yield (11.3 t/ha) with foliar application of 7.5 percent Kappaphycus alvarezii seaweed sap four times, plus RDF and two foliar applications of 10% K-sap yielded the greatest harvest index (32.7%).