Abstract:

The study aims to evaluate the effects of three afforestation methods on soil organic carbon (SOC) and provide a scientific basis for ecological restoration and carbon sequestration management in sparse forest lands. In Qingtian County, Zhejiang Province, three afforestation approaches were implemented: single-species, two-species and multi-species (five species) plantations, followed by a comprehensive soil property analysis. The results showed that compared with single-species and two-species afforestation, multi-species afforestation significantly increased SOC content. Correlation analysis demonstrated that SOC levels were significantly associated with soil total nitrogen and available nitrogen. Multi-species afforestation enhanced SOC content in sparse forest lands through three synergistic mechanisms: increasing organic carbon input, improving soil nitrogen and potassium availability, and elevating soil enzyme activity. These findings advance scientific guidance for ecological restoration and carbon sequestration management in sparse forest lands, while underscoring the critical role of soil carbon-nitrogen-potassium coupling dynamics and microbial enzyme activity in soil carbon cycling.

Key words: afforestation, soil, sparse forest lands, organic carbon, soil properties