The regulatory effects of sweet potato rotation patterns on soil organic carbon components and carbon-transforming enzyme activities

This study systematically evaluated the effects of different sweet potato rotation patterns on soil organic carbon components and carbon-transforming enzyme activities to reveal the regulatory mechanisms of crop rotation on soil carbon cycling. The experiment included continuous sweet potato–wheat cropping (SWS) and three rotation patterns: sweet potato–wheat/sweet potato–rapeseed (SWR), sweet potato–wheat/maize–wheat (SWC), and sweet potato–wheat/peanut–wheat (SWP). Soil samples were collected from 0–20 cm and 20–40 cm layers to determine soil organic carbon (SOC), dissolved organic carbon (DOC), particulate organic carbon (POC), readily oxidizable organic carbon (ROC), microbial biomass carbon (MBC), and the activities of related carbon-transforming enzymes (sucrase, cellulase, polyphenol oxidase, peroxidase). The results showed that crop rotation significantly increased the contents of soil organic carbon components and enzyme activities, with notable differences among rotation patterns; SWC and SWP exhibited stronger promoting effects than SWR. Further analysis revealed significant correlations between soil organic carbon components and carbon-transforming enzyme activities, suggesting their synergistic roles in carbon cycling. This study innovatively compared multiple sweet potato rotation patterns and, for the first time, systematically revealed the differential responses of soil layers to rotation, thereby expanding the research perspective on the biochemical mechanisms of soil carbon cycling. The findings provide theoretical support for optimizing sweet potato rotation systems and managing soil health, offering important implications for promoting sustainable agricultural development.