Isotope analysis reveals differential impacts of artificial and natural afforestation on soil organic carbon dynamics in abandoned farmland

A multitude of studies analyzed the dynamics soil organic carbon (SOC), but their methodology does not provide sufficient understanding differential impact artificial and natural afforestation on SOC dynamic. We investigated following (AR) (NQ) abandoned farmland (AF) in China’s Loess Plateau an attempt to evaluate effects these methods. characterized structure stoichiometry using stable isotope radiocarbon models. aim compare dynamics, clarify sources under different afforestation, examine comparability study areas ascertain how aggregate size classes control dynamics. The 0-10 cm 10-20 stocks were significant higher NQ than AR AF. At other depths, there is no difference among three land-use systems. Total topsoil stocks, C:N C:P differently sized aggregates significantly increased afforestation. Carbon analysis results indicated that decomposition rate new input lower AR. Afforestation can lead accumulation depths up 1m mainly because (0-20 cm) changes significantly. resources are from macroaggregate formation provided by fresh plant residues. sites validated, so the“space-for-time substitution” method applicable this study.