Below-ground litter decomposition in the Otindag Sandy Land

Litter decomposition drives carbon and nutrient cycling in complex sandy grassland ecosystems of arid and semiarid regions. A one-year field experiment was conducted in the Otindag Sandy Land using standardized litter materials—readily decomposable green tea and more recalcitrant red tea—to simulate belowground decomposition across four grassland types (desert, sandy, typical, and open forest grasslands/temperate savanna). High-throughput sequencing was employed to assess soil bacterial and fungal community composition and diversity, enabling evaluation of tea bag mass loss as influenced by biotic (e.g., plant and microbial diversity) and abiotic (e.g., climate, soil properties) factors and their interactions. Green tea decomposed fastest in temperate savanna, followed by typical, desert, and sandy grasslands; red tea decomposition did not differ significantly among sites. Green tea loss was primarily driven by biotic factors, whereas red tea decay was affected by both biotic and environmental variables. Further analysis indicated that climate (temperature, precipitation) and plant diversity indirectly influenced decomposition by modulating microbial diversity. Our study offers valuable insights into nutrient cycling and ecosystem functioning in dryland areas.