How land-use types and plantation chronosequences affect soil organic carbon (SOC) content, characteristics, and stability in arid Northwest China's forestry farming systems is poorly understood. The influence of land-use types (farmlands versus wolfberry orchards) and the chronosequences of wolfberry plantations aged 1, 4, 6, 10, and 13 years on the physical compartments, structure of chemicals, and stabilization pathways of SOC in aggregate-sized fractions were examined using a scanning electronic microscope (SEM) and energy-dispersive X-ray spectroscopy (EDS), solid-state C-13 NMR, and C-13-isotopic methods. SOC content decreased under farmland (FL) and short-term (<4 year) cultivation of wolfberry, but increased after >4 year. Long-term wolfberry (>10 year) physically protected SOC by enhancing macro-aggregates (>0.25 mm), significantly increasing light fraction carbon (LF-C, +92.1%) and coarse particulate organic carbon (cPOC, +67.7%) in macro-aggregates compared to FL. Wolfberry cultivation decreased mineral-associated organic carbon (mSOC), especially in macro-aggregates after >4 year. Resistant components (alkyl and aromatic C) increased with plantation age. Wolfberry cultivation elevated alkyl C/O-alkyl C ratios and lowered aliphatic/aromatic C ratios, enhancing chemical stability. Values of delta C-13 were enriched and depleted following the cultivation of wolfberry for short and long durations, respectively. C flowed from aggregates to silt + clay (<0.053 mm) in FL and short-term wolfberry, but reversed direction after >4 year. Long-term wolfberry cultivation enhances SOC assembly and stabilization via physical protection in aggregates and increased chemical recalcitrance. Both land-use and plantation age critically influence the direction of C flows among aggregate size classes.