ABSTRACT Bio‐fertilizer, as an environmentally friendly fertilizer, combined with the application of controlled‐release nitrogen (CRN), contributes to increasing rice yield. However, research on the synergistic effects of blended CRN with conventional urea (CU) combined with bio‐fertilizer on the yield, quality, and nitrogen (N) utilization of japonica rice remains limited. Therefore, this study selected the high‐quality japonica rice variety Nanjing 9108 and conducted a 2‐year field experiment with five fertilization treatments: no N fertilizer, 0N (used only for calculating fertilizer use efficiency); application of CU, CU; CU combined with bio‐fertilizer, CU‐Bio; application of 70% CRN blended with 30% CU, CRBBF; and application of 70% CRN blended with 30% CU combined with bio‐fertilizer, CRBBF‐Bio. The results showed that compared with CU, the treatments of CU‐Bio, CRBBF, and CRBBF‐Bio all increased rice yield by 7.48%, 8.34%, and 13.23% in the 2023 and by 8.07%, 8.74%, and 14.99% in the 2024, respectively. This improvement was primarily attributed to the synergistic increase in total spikelet number, seed‐setting rate, and 1000‐grain weight. Meanwhile, dry matter accumulation at different growth stages, leaf area index (LAI), as well as net photosynthetic rate and soil and plant analyzer development (SPAD) value at the heading stage were significantly enhanced, with the CRBBF‐Bio treatment showing the most pronounced effects. Furthermore, CU‐Bio, CRBBF, and CRBBF‐Bio improved rice quality, significantly increasing head rice rate while significantly reducing chalkiness degree and chalky grain percentage. Additionally, taste value increased due to a reduction in amylose content. In terms of physiological mechanisms, CU‐Bio, CRBBF, and CRBBF‐Bio significantly enhanced the activities of NR, GS, and GOGAT, promoted N uptake and accumulation across growth stages, and ultimately increased N recovery efficiency (NRE) by 12.08%, 15.49%, and 22.42% in the 2023 and by 12.91%, 16.31%, and 25.38% in the 2024, respectively. These findings effectively advance the practice of high‐yield and high‐quality rice cultivation and are of great importance for ensuring food security.
Xu et al. (Thu,) studied this question.