The Conservation Reserve Program (CRP) may help to improve soil quality and mitigate the greenhouse effect through carbon (C) sequestration, but few studies have assessed the overall impacts using robust statistical analysis. We selected 14-paired (adjacent) CRP and cropland sites in Dane County, WI on silt loam soils to (1) examine how the CRP had affected several soil quality indicators and (2) assess whether a paired-site approach could be used to detect statistically significant differences (ANOVA) in soil organic C and nitrogen (N) storage between land-use types to determine rates of C and N sequestration. We compared surface (0-10 cm) bulk density and soil moisture, organic matter (OM), soil organic C (SOC), N, pH, C:N, and C:OM from depth intervals of 0-5 cm, 5-10 cm, and 10-25 cm. Data indicated that the CRP had lowered bulk density by 13% (p < 0.0001), significantly increased 0-10 cm soil water retention (p = 0.01), and increased soil organic C, N, and OM concentration (g kg-1) by 27-31% (p < 0.05) in the surface (0-5 cm) layer. At soil depths greater than 5 cm, no significant differences were noted between any of the soil quantities measured. The coefficient of variation (CV) for these soil quantities indicated that soil pH and bulk density were less variable (CVs < 10%) than SOC and N (CVs 20-30%) across soils sampled within the county. Rates of soil C and N sequestration in the surface 5 cm averaged 24.7 g C m-2 yr-1 and 1.7 g N m-2 yr-1, respectively, but possessed CVs of 146% and 239%. We tested the statistical power associated with ANOVA for soil C, N, OM and bulk density, and calculated a minimum detectable difference (MDD) for these quantities. We found that only surface bulk density differences possessed good statistical power (1-b > 0.98), whereas the confidence level was 67-79% for soil C, N, and OM concentration data. When soil C, N, and OM were compared on a mass basis (kg m-2), the power analysis indicated that we would need approximately 60-80 paired sites to achieve a 90% confidence level for C sequestration calculations. This analysis showed that we could only detect a 15% change in existing total SOC pools, suggesting SOC storage varies considerably across this small geographic region.