From growth to decline: The dynamic effects of maize-based cropping systems on soil organic carbon storage in Northeast China

Continuous maize cultivation in Northeast China has resulted in soil degradation and a decline in soil organic carbon (SOC) storage. Diversified maize-based cropping systems offer a promising strategy for restoring soil health and enhancing SOC sequestration. However, their long-term impacts, the key driving factors influencing SOC dynamics, and the spatial variability in SOC responses remain insufficiently understood. In this study, we employed a Genetic Algorithm-Random Forest (GA-RF) model to identify the key factors affecting SOC storage under maize-based diversified cropping systems. Focusing on the prevailing maize-based cropping patterns in Northeast China, we examined the spatiotemporal effects of maize-based rotation systems on SOC storage. The results indicated that the SOC storage under maize-based rotations was influenced by management practices (e.g., duration and intensity of crop rotation), meteorological factors (such as mean annual precipitation), and initial soil conditions including bulk density and total nitrogen content. The greatest potential for enhancing SOC storage was observed in regions with high initial soil fertility and abundant rainfall. Maize-based rotations implemented between 2010 and 2018 in Northeast China increased SOC storage in the 0–20 cm soil layer by 0.53 % (≈15.86 Tg). In comparison, optimized maize-soybean rotation scenarios have the potential to raise SOC storage by 1.48–3.21 % (≈33.44–72.53 Tg). As the intensity of maize-based diversified rotation increased, SOC storage underwent phases of rapid increase, gradual growth, stagnation, and decline. Consequently, implementing an annually alternating maize-soybean rotation over five consecutive years was found to be the most effective strategy for enhancing SOC storage and providing practical insights for improving soil quality and promoting the sustainable development of maize-based agriculture in Northeast China.