This study was initiated to better understand the role of WSOC in the process of sequestering carbon in mixed species grassland as compared to cropland systems. Previously established mixed-species grassland plot sites near Kindred (Ekre Ranch), Carrington and Dickinson, ND were evaluated for differences in WSOC due to species, species richness, fertility management and/or harvest management. Soils were extracted with a 1:2 (w/v) soil:deionized water solution to determine WSOC. Analysis of variance and Tukey-Kramer HSD were used to determine if individual species, species richness, harvest frequency, and fertilizer application affected WSOC. Generally, WSOC decreased with increasing soil depth and made up 5.36, 5.75, and 6.27% of total OC for Ekre Ranch, Carrington, and Dickinson, respectively. Individual species showed greater WSOC compared to cropland checks, but there was no difference among species. Species richness and harvest frequency had no effect on WSOC, while WSOC near the soil surface at Ekre Ranch was influenced by phosphorus fertilizer applications and nitrogen fertilizer applications affected subsoil WSOC. Knowing how WSOC reacts to these treatments over the short-term can be used to maximize carbon sequestration as well as increasing both near-term and long-term productivity and profitability in agricultural settings.