The study tested different fertilization levels and plant spacings for growing middle rice using mechanized transplanting in the south mountain region. Results showed that using a medium level of fertilizer and a plant spacing of 11.7 cm led to the highest grain yield. Increasing fertilizer application rate boosted tiller growth and dry matter in leaves and stems. The highest dry matter in panicles, harvest index, and grain yield were observed with medium fertilization. Planting at 11.7 cm spacing resulted in the highest grain yield compared to wider spacings. Overall, using medium fertilization and closer plant spacing can increase rice yield in mechanized transplanting conditions.