Photosynthetic Attributes and Carbohydrates in Relation to Yield of Aerobic Rice As Influenced by Nitrogen and Sea Weed Extract Application

The aerobic rice system is water saving strategy in agriculture but its production was increasingly limited under these conditions. The field experiment was conducted to assess the effect of different doses of nitrogen (90, 110 and 125 kg/acre) and sea weed extract (SWE) application (8, 12 and 16 kg/acre) on photosynthetic and yield attributes of two rice cultivars PR 116 and PR 120 under aerobic condition. The experiment was laid out in factorial randomized block design with three replications. The chlorophyll and carotenoid content were recorded low under aerobic conditions as compared to control. The application of nitrogen @ 125 kg/acre enhanced photosynthetic pigments and hill reaction activity in both cultivars but effect was found to be more pronounced in PR 120 as compared to PR 116. The carbohydrate content was recorded low in PR 116 when low level of nitrogen @ 90 kg/acre was applied, but the application of SWE at different doses showed promotory effect on carbon content. The application of SWE also enhanced grain and straw yield in both cultivars but effect was found to be more pronounced in PR 120. Thus, it was concluded that SWE could be used as an alternate to chemical fertilizer to enhance rice production under aerobic condition.