We developed a general, synthetic model to examine the interactions between buried litter, decomposer microorganisms, and C and N pools in this ecosystem. Our goal is to explore the mechanisms underlying observed patterns of decomposition in arid systems using a modeling approach that balances simplicity with enough detail to suggest the reasons for system behavior.... This study indicates that the pattern of microbial activities, accounting for the decomposition of buried materials in the absence of termites, is primarily determined by climatic conditions.