Pomegranate (Punica granatum L.), a high-value fruit crop widely cultivated in semi-arid and semi-humid regions, has driven large-scale conversion of conventional croplands into orchards in response to rising global market demand. However, the ecological impacts of this land-use change, particularly how stand age influences the composition and structure of soil nematode communities, remain poorly understood. Using a chronosequence approach, we investigated the effects of orchard establishment on soil nematode communities across different stand ages (1, 3, 5, and 10 years after establishment), with adjacent croplands serving as reference. Compared to conventional farmland, one-year-old plantations exhibited a 53.08% reduction in bacterivorous nematodes and a striking 316.73% increase in fungivorous nematodes (P < 0.05). Stand age significantly affected the Pielou evenness index, nematode channel ratio, maturity index, and basal index of the soil nematode community. Total nematode metabolic footprints, as well as enrichment footprint and structure footprint, peaked in 5-year-old orchards. Pearson correlation analysis revealed that the relative abundance of bacterial feeders and the nematode channel ratio were significantly negatively correlated with soil total phosphorus content. The maturity index was positively correlated with soil fungal biomass. NMDS ordination indicated that stand age is a primary driver of nematode community composition, while RDA analysis identified soil total phosphorus, carbon, nitrogen, fungal microbial biomass as key explanatory variables. Our results demonstrate that the age of pomegranate orchards drives significant successional shifts in soil nematode community structure and function, reflecting age-dependent ecosystem development in orchard soils. This study identifies the five-year stage as an ecological tipping point characterized by peak biological activity and optimal nutrient cycling efficiency. These insights support the design of precisely timed management interventions to prolong this productive phase, offering practical strategies for maintaining long-term soil health in orchard ecosystems.