I hypothesized that the relative proportion of grasses and legumes in native prairie communities are associated with physical and chemical soil properties. In a greenhouse study, I determined species responses to differences in soils ex situ by individually growing three grasses, two legumes, and two composites in soils from four sites on a never-plowed prairie at The Land Institute in Saline County, KS. The highest organic matter (OM) soil produced the highest plant dry matter for five of the species. In a field study, I measured 20 soil properties in 24 quadrats (0.5 m2) with high, low, or no legume cover on the same four sites. After incubation, NH4 in subsurface soils was lower for high legume cover suggesting higher nitrification. Discriminant multivariate analysis showed the ratio, active C as a percent of total C, and percent OM were the most closely associated surface soil variables with percent legume cover.