To address the growing pressure of rising labor and fertilizer costs in high-quality japonica rice production in Jiangsu Province, as well as to resolve the labor-intensive and time-consuming challenges of traditional split fertilization, it is imperative to develop mechanized cultivation technologies that are simplified, high-yielding, and efficient. This study used high-quality japonica rice Nangeng 5718 and Nangeng 9108 as the test materials, and conducted field experiments across different ecological zones. The aim was to investigate the effects of a one-time basal application of controlled-release blended fertilizer combined with wide-narrow row pot-seedling machine transplanting on rice yield and nitrogen use efficiency. Results showed that this technology significantly increased yields across all regions: In Xiangshui of Yanchen, the treatment combining wide-narrow row pot-seedling machine transplanting with “50% quick-acting N+10% 40-day controlled-release fertilizer+40% 80-day controlled-release fertilizer” yielded 58.67 kg/667 m² more than the conventional fertilization treatment (control), representing an increase of 8.14%. In Xinghua of Taizhou, the treatment with “50% quick-acting N+10% 40-day controlled-release fertilizer+40% 100-day controlled-release fertilizer” resulted in a yield increase of 49.33 kg/667 m² over the control (i.e, 7.35%). In Haian of Nantong, the treatment using “50% quick-acting N+10% 80-day controlled-release fertilizer+40% 100-day controlled-release fertilizer” achieved a yield gain of 32.00 kg/667 m² compared to the control, equivalent to a 4.85% increase. Mechanism analysis revealed that the yield-enhancing and efficiency-boosting effects resulted from synergistic interactions among multiple factors: Wide-narrow row configuration improved ventilation and light penetration within the rice canopy, leveraging edge advantages to foster the development of a high-light-efficiency population, thereby significantly increasing leaf area index and photosynthetic potential. Pot-seedling transplanting with soil clods reduced transplanting injury, shortened the recovery period, and facilitated the formation of robust stems and large panicles, leading to marked increases in effective panicle number and spikelet count. The integration of quick-acting and controlled-release fertilizers precisely matched rice nitrogen demand across different growth stages, enhanced nitrogen use efficiency, and ensured vigorous late-stage photosynthetic production and dry matter accumulation. In conclusion, the one-time basal application of controlled-release blended fertilizer combined with wide-narrow row pot-seedling machine transplanting integrates multiple simplifications and emerges as an efficient and practical technology for boosting both yield and resource use efficiency in high-quality japonica rice production in Jiangsu Province, with broad prospects for promotion and application.