Purpose <p>Nitrogen deficiency and competition improve intercropped sugarcane productivity only to a limited extent. Fenlong tillage enhances yield by breaking the plow pan, increasing soil nitrogen supply, and improving crop nitrogen status. Wide–narrow rows alleviate interspecific nitrogen competition. Therefore, intercropping centered on Fenlong tillage is conducive to improving agricultural productivity.</p> Methods <p>A two-cycle field experiment was conducted to evaluate how planting methods—sole ratoon sugarcane cropping (S) and ratoon sugarcane–soybean intercropping (I)—combined with tillage methods—conventional rotary tillage (RT) and Fenlong tillage “145” mode (FL145)—affect soil nitrogen status, ratoon sugarcane nitrogen metabolism, nitrogen accumulation, and yield.</p> Results <p>Under FL145-I, soil alkali-hydrolyzed nitrogen content and urease activity increased by 9.94–18.08% and 12.10–12.74%, respectively, compared to RT-I. Stalk nitrogen content, leaf nitrogen content, nitrate reductase activity, glutamine synthetase activity, plant nitrogen accumulation, and stalk dry matter accumulation increased by 21.25–34.27%, 6.36–11.50%, 19.14–28.59%, 15.18–21.25%, 37.85–45.19%, and 20.53–23.00%, respectively. FL145-I increased stalk and sugar yields by 17.13–22.55% and 19.20–21.30%, respectively. Wide–narrow row intercropping exerted no negative effects on ratoon sugarcane nitrogen accumulation or yield.</p> Conclusion <p>Intercropping with Fenlong tillage “145” mode (FL145-I) positively affected soil nitrogen availability and leaf nitrogen metabolism in ratoon sugarcane, increasing nitrogen accumulation (14.78&#xa0;g·plant^− 1–16.39&#xa0;g·plant^− 1), resulting in higher stalk yield (81.03 t·ha^− 1–90.21 t·ha^− 1) and sugar yield (13.78 t·ha^− 1–14.96 t·ha^− 1). Therefore, FL145-I emerges as a promising and novel management approach for enhancing ratoon sugarcane nitrogen accumulation and yield in China.</p>