This data set reports the results of lab-scale experiments conducted to investigate the dynamics of organic carbon (C) decomposition from several soils from temperate, tropical, arctic, and sub-arctic environments. Results were used to test the newly developed soil microbe decomposition C model--Microbial-ENzyme-medicated Decomposition (MEND). We conducted a series of laboratory-scale experiments to better understand the microbial processing of organic C in response to diverse substrates and soil types, and to provide data to create an improved mechanistic model of cycling of organic C in soils. The interaction of diverse substrate types on a global suite of soils was determined in batch sorption experiments and the microbial decomposition of these compounds was determined by long-term incubation experiments. We used radiocarbon labeling approach in order to study the turnover of added substrate C through different C pools and to separately quantify the respiration of substrate C and native soil organic carbon.