Kucharik, C.J. Impact of Prairie age and soil order on carbon and nitrogen sequestration. The Soil Science Society of America Journal. 12 March 2007; doi,10.2136/sssaj2006.0074, 2007 71: 430-441

Abstract:

Conservation Reserve Program (CRP) prairie restorations can sequester carbon (C) and nitrogen (N) into soils, but the effects of soil order and ecosystem age are still not well understood. Soil bulk density (BD) in the top 20 cm and soil organic C (SOC) and N (SON) densities in 0-5, 5-10, and 10-25 cm depth intervals were measured at 39 paired CRP-crop sites in Wisconsin to quantify SOC and SON sequestration as a function of three planted prairie age groupings (4-5, 6-10, and 11-16 yrs) and two soil orders (Alfisols and Mollisols). Alfisol soil BD in the 0-10 cm layer decreased significantly (-0.11 g cm-3, P < 0.0001), but changes were not significant on Mollisols (-0.07, P = 0.27). SOC and SON sequestration (47.9 g C m-2 yr-1 and 3.1 g N m-2 yr-1, respectively) was limited (P < 0.05) to the top 5 cm across all paired sites. While SOC sequestration was three times greater on Alfisols (62 120 g C m-2 yr-1) than Mollisols (22 111 g C m-2 yr-1), and the youngest prairies (4-5 yrs) had sequestered SOC at an average rate (74 165 g C m-2 yr-1) that was higher than the oldest (11-16 yrs) (16 28 g C m-2 yr-1), the effects of soil order and age grouping were not significant (P > 0.05). However, SOC sequestration rates on Alfisols associated with the youngest prairies (103 163 g C m-2 yr-1) were greater (P < 0.1) than the oldest prairies (10 30 g C m-2 yr-1), suggesting a diminishing rate of SOC accumulation over time.