Effects of vermicompost on growth and yield of Japonica rice (Koshihikari Var.) in Thailand.

Significant differences were observed in plant height, number of tillers, and chlorophyll content. The 10% vermicompost treatment resulted in the tallest plants at 88 days. The combined vermicompost and chemical fertilizer treatment (T8) produced the highest number of tillers, though it did not differ significantly from the 20% vermicompost treatment (T4). Over time, vermicompost-amended treatments outperformed chemical fertilizer alone in most growth and yield parameters. Treatment 5 yielded the highest total seed count, while T4 resulted in the healthiest seeds and the greatest total fresh and dry seed weights. T4 also had the widest, longest, and thickest seeds, with a fivefold increase in total dry seed weight compared to the control. These findings strongly supported the application of vermicompost particularly at 10–30% for improved Japonica rice growth and yield, highlighting its potential for organic production systems.