This dataset includes measurements of microbial community composition by phospholipid fatty acid (PLFA) analysis, soil respiration (Carbon dioxide (CO2)), soil physico-chemical properties and 13C enrichment in CO2 samples and microbial Phospholipid Fatty Acids (PLFAs). Data were produced for an investigation of the effects of carbon (C) substrate addition on soil carbon cycling processes in ten tropical soils from the Peruvian Andes. Soils were amended with 13C labelled substrates (xylose, glycine, vanillin and hemicellulose) and incubated under controlled conditions for 7 days.