Integrating legume rotation and optimal nitrogen management enhances cotton yield and mitigates greenhouse gas emissions in a jujube-cotton intercropping system

Enhancing crop productivity while minimizing environmental impacts remains a central goal of sustainable agriculture. While legume rotation and nitrogen management have shown efficacy in curbing synthetic fertilizer dependency, most previous studies have focused on monoculture systems or individual management practices, with little attention to their combined effects in jujube-cotton intercropping. We hypothesized that integrating legume rotation with optimal nitrogen fertilization can synergistically increase cotton yields and reduce greenhouse gas emissions. A field experiment was conducted using a split-plot design to compare continuous cotton cultivation (M) with a cotton-alfalfa rotation (R) under four nitrogen application rates (0, 140, 280, 420 kg N ha −1 ). Cotton yield, greenhouse gas emissions, soil health, and net ecosystem economic benefits were evaluated. Compared to continuous cropping, rotation reduced the average annual CO 2 and N 2 O emissions by 13.80 % and 21.09 %, respectively, over the two-year period, while decreasing the average annual greenhouse gas emission intensity by 29.74 %. Rotation also improved the soil quality index by 41.35 % and increased cotton yield by 23.80 %. At 280 kg N ha −1 , greenhouse gas emission intensity declined by 16.82 % on average compared with other nitrogen rates. Optimized nitrogen application yielded a 15.60 % increase in yield relative to other rates. The rotation and the 280 kg N ha −1 treatment significantly improved yield stability and sustainability, leading to the highest net ecosystem economic benefits. Our findings highlight the pivotal role of integrating legume rotation with optimal nitrogen management in improving productivity and environmental sustainability in jujube-cotton intercropping systems, offering a promising pathway to sustainable production. • We conducted the first legume rotation trial in a jujube-cotton intercropping system, integrated with nitrogen design. • Legume rotation raised the soil quality index by 41.25%; optimizing to 280 kg N ha -1 increased cotton yield by 15.60%. • Versus continuous cropping, legume rotation cut cumulative CO 2 and N 2 O by 13.80%/21.09% and increased yield by 23.80%. • This establishes a yield-enhancing, emission-reducing model for jujube-cotton system: legume rotation + 280 kg N ha -1 .