Soil properties were assessed to determine the effects of tillage agriculture on soil-quality-related parameters of former tallgrass prairie. Soil physical, chemical and biological properties were evaluated in the top 10 cm at six native grassland sites within the Grand Prairie region of east-central Arkansas and compared with adjacent tilled agricultural land in a total of 11 prairie-agriculture land-use combinations. Soil organic matter and total C and N concentrations were significantly lower and soil pH, electrical conductivity and extractable soil P, K, Ca, Mg, Fe were significantly higher under tilled agriculture than under native prairie land use. The introduction and continuance of intense mechanized agriculture and its associated practices have significantly, and for the most part negatively, impacted native soil quality in this region. These results will aid prairie restoration efforts by identifying soil properties most impacted by cultivated agriculture and those that may be desirable to restore and providing potential restoration targets based on native soil properties.