Objective The interaction between main-season fertilization regimes and seeding rates was studied for its effects on yield formation, dry matter accumulation, and grain quality of aromatic ratoon rice aiming to provide an optimized cultivation strategy for high yield and good quality of aromatic ratoon rice.

Method A two-year (2023—2024) field experiment was conducted using the aromatic rice cultivar ‘Meixiangzhan 2’. A split-plot design was adopted, with fertilization regime as the main plot. There were five main-season fertilization treatments: CK (unfertilized control), F1 (compound fertilizer alone), F2 (compound fertilizer plus organic fertilizer), F3 (special fertilizer for aromatic rice alone), and F4 (special fertilizer plus organic fertilizer). The seeding rate was the subplot, with two levels including conventional seeding rate (D) and high seeding rate (G). Indices including yield, grain quality, dry matter accumulation, and photosynthetic characteristics of the aromatic ratoon rice were measured and analyzed.

Result The interaction between main-season fertilization regime and seeding rate significantly affected the annual yield and quality of aromatic ratoon rice. The F3G (special fertilizer for aromatic rice with high seeding rate) treatment performed the best, with annual yields of 9.60 and 9.89 t hm⁻² in the two years, respectively; the F4G (special fertilizer plus organic fertilizer with high seeding rate) treatment ranked second. The yield increase was primarily attributed to the increased effective panicle numbers in both the main and ratoon seasons. The appropriate main-season fertilization regimes under high seeding rate (F3G and F4G) also significantly (P<0.05) enhanced dry matter accumulation capacity during the middle and late stages of the main season. Moreover, the dry matter weight at the main season heading stage was significantly (P<0.01) positively correlated with the ratoon season yield, laying a solid material foundation for high yield in the ratoon season. In addition, processing quality exhibited significant inter-annual variation. In 2024, the F4G treatment significantly (P<0.05) increased the milled rice rate in the main season, while under the high seeding rates in the ratooning season, the milled rice rate decreased in some treatments.

Conclusion Adopting a cultivation model with a high seeding rate combined with main-season application of special fertilizer for aromatic rice or special fertilizer plus organic fertilizer can effectively optimize biomass accumulation, promote dry matter production and allocation, and is a feasible strategy for achieving synergistic improvement in annual yield and quality of aromatic ratoon rice.