| A field experiment on the sorghum variety ‘Liaoza 52’ was conducted in 2021-2022 to investigate the effects of row spacing, reflective film mulching, and nitrogen fertilizer on its photosynthetic characteristics, yield, and quality. The experiment used a three\|factor split\|plot design with varying row spacings (50 cm for A1 and 60 cm for A2), reflective film treatments (no mulching for B1 and mulching for B2), and nitrogen fertilizer levels (150 kg·hm-2 for C1, 300 kg·hm-2 for C2, and 450 kg·hm-2 for C3). The results showed that experimental factors and their interaction effect had the significant effect on sorghum yield (P<0.05). The row spacing of 60 cm yield increased by 5.12% than that of row spacing of 50 cm, yield of reflective film mulching increased by 7.73% than that of no reflective film mulching, and C3 yield was the highest with 6 807.0 kg·hm-2 and increased by 3.90%~9.48% than that of others. Experimental factors and their interaction had the significant effect on the SPAD value and Pn of sorghum leaf. Enlarge row spacing increased the SPAD value and Pn of the sorghum leaf in the heading stage, postulation stage, and dough stage, and reflective film mulching, and nitrogen fertilizer increased the SPAD value and Pn of the sorghum leaf in the tested stage. Enlarge row spacing and reflective film mulching increased sorghum seed protein content by 6.94% and 2.84%, respectively. Sorghum seed protein content of C3 was increased by 2.50% than that of others. Enlarge row spacing and reflective film mulching increased sorghum seed starch content by 1.75% and 0.70%, respectively. Sorghum seed starch content of C3 was increased by 3.85% than that of others. However, increased row spacing, the use of reflective film mulching, and nitrogen fertilizer resulted in a reduction in the fat content of sorghum seeds. A row spacing of 60 cm, reflective film mulching, and the application of nitrogen fertilizer at 450 kg·hm-2 during the elongation stage proved to be an effective cultivation combination for enhancing both yield and seed quality. This was achieved through more efficient use of light and temperature, as well as improved photosynthetic performance of sorghum leaves. |