Evaluation of the Effect of Rice Straw-Based Compost on Rice Brown Spot Caused by <i>Bipolaris oryzae</i> in Strict Rainfed Rice Cultivation

In order to contribute to the improvement of rice production in Côte d’Ivoire, through sustainable management of the diseases that reduce its production, the effect of rice straw-based compost was evaluated on rice brown spot. Five doses of this compost, namely 0, 2.5, 5, 7.5, and 10 t. ha−1, were studied in a completely randomized Fisher block design with three replications. A total of 15 plots of 12 m2 were delimited. The traditional Gbéklélé variety of rainfed rice was sown in aligned stacks 0.2 m apart. Rice brown spot severity was scored using the IRRI standard rating scale at a frequency of 15 days from tillering to maturity. The number of tillers (total and fertile), height on 25 plants, yield and paddy yield gain per treatment were determined. The results showed that the addition of rice straw compost had an impact on disease expression. The compost dose of 7.5 t. ha−1 reduced rice brown spot pressure, with a severity index of 3.89 and a yield of 2.18 t. ha−1. This study shows that the application of 7.5 t. ha−1 of rice straw-based compost effectively reduced rice brown spot pressure in rice, with a 74% gain in paddy yield.