Response of rice husk biochar coating on seed quality and productivity of rice in Fogera Plain, Ethiopia

Abstract The primary factors contributing to poor seed quality and lower rice yields are largely attributed to inadequate seed quality management strategies. The quality of rice seeds and productivity in the Fogera Plain of Ethiopia suffer from prolonged seedling emergence, and insufficient seedling growth. Coating rice seeds with rice husk biochar (RHB) can significantly enhance seed quality and productivity. However, researchers have not yet investigated the optimal ratio of RHB to rice seeds for effective coating in the region. Therefore, this experiment was conducted both in a greenhouse and laboratory conditions to evaluate seed quality characteristics and the impact of varying concentrations of RHB on rice seed quality and productivity. A completely randomized design was employed with three replications, testing RHB at ratios of 0%, 10%, 20%, 30%, and 40% grams of RHB per kilogram of rice seeds. Accordingly, our findings indicated that a coating of 20% of RHB with rice seeds significantly (P ≤ 0.05) improved the standard germination percentage, germination speed, and vigor index I compared to the other treatments. Furthermore, this treatment notably increased grain yield, above-ground biomass, and panicle length compared to the control group. In this respect, the results demonstrate that 20% of RHB treated rice seeds yielded higher grain output but also exhibited a more substantial response to biochar seed coating, resulting in a net benefit of 302,800 ETB per hectare, compared to 182,500 ETB per hectare for the control. It is advisable to use a coating concentration of 20% of RHB in proportion with rice seeds as an effective management strategy to promote early germination, enhance vigor, increase grain yield and reduced grain discoloration in Fogera Plain and similar rain-fed rice growing regions.