Optimal N management improves crop yields and soil carbon, nitrogen sequestration in Chinese cabbage-maize rotation

Appropriate nitrogen (N) fertilization in vegetable-maize rotations is effective in improving agricultural production and mitigating environmental impacts to ensure sustainable food security. The dynamic and sustainability of crop yields, crop root biomasses, and accumulations and sequestration rates of soil organic C (SOC) and total N (STN) were explored and analyzed under four N application rates (kg N ha−1 year−1): 0 (Control), 285 (Low-N), 480 (Medium-N), and 720 (High-N). The Low-N and Medium-N applications increased Chinese cabbage yield by 22% and 20.7% than the High-N application, respectively. The Medium-N application gained the highest grain yield and root biomass in the maize season when compared with the Low-N application. The sustainable yield index had no difference between Low-N and Medium-N treatments in Chinese cabbage-maize rotation. Compared to the Low-N application, the Medium-N application improved the storage and sequestration rates of SOC and STN. Simultaneously, the Medium-N application significantly enhanced the soil C:N ratio than the High-N application. In conclusion, the Medium-N application is a promising fertilization strategy in the Chinese cabbage-maize cropping system as it increases the yield and root biomass of crops, improves the accumulation and sequestration rates of SOC and STN, and maintains a high soil C:N ratio.