Incorporating crop rotation into the winter wheat-summer maize system to enhance soil multifunctionality and sustainable grain production in the North China Plain

Context: The winter wheat-summer maize double cropping system has long been a dominant practice in the North China Plain. However, its continuous use has led to soil fertility decline, biodiversity losses, and nutrient imbalances, thus threatening grain production sustainability. Crop rotations are of great essential to enhance soil health and resilience, but its benefits for the winter wheat-summer maize system in this region remain poorly understood. Objective: This study evaluates the effects of incorporating crop rotations into the winter wheat-summer maize system to mitigate soil degradation, enhance soil multifunctionality (SMF), and maintain high grain yield production. Method: A field experiment (2018-2022) compared three crop rotation systems, spring sweet potato-* winter wheat-summer maize (Psw-WM), spring peanut-* winter wheat-summer maize (Pns-WM), and spring sorghum-* winter wheat-summer maize (Sor-WM), against continuous wheat-maize cropping (WM-WM). The winter wheat and summer maize yields were assessed annually, and soil physicochemical properties, enzyme activities, and rhizosphere microbial communities were analyzed during the second crop cycle to assess SMF. Results: Compared to WM-WM, the Pns-WM and Psw-WM significantly increased annual winter wheat and summer maize yields by 8.12 %-11.39 % and 8.78 %-15.82 %, respectively. Compared to WM-WM, these rotations (Pns-WM and Psw-WM) enhanced SMF by 1- to 2-fold due to increased soil organic carbon (SOC), improved enzyme activities, and better nutrient cycling. The lower pH and higher bacterial and fungal richness (e.g. ACE indices) were found in Pns-WM and Psw-WM, as compared to WM-WM. Furthermore, Pns-WM increased beneficial genus such as Penicillium and Fusarium while reducing pathogenic taxa like Alternaria. Partial least squares structural equation modeling illustrated that improved SOC, enzyme activities, and microbial diversity drove the increases in SMF and grain yield in the Pns-WM and Psw-WM. Conclusion: Integrating peanut or sweet potato into the winter wheat-summer maize system effectively enhances soil health, SMF, and grain yield. Thus, introducing annual crops as preceding crops to the current WM-WM rotation is beneficial for fostering microbial diversity and enzyme activities, improving soil properties, enhancing grain yield, and providing a sustainable pathway for resilient food production in the NCP and similar agroecosystems.