Abstract:

In Wisconsin, fewer than 800 ha of the estimated 850 000 ha of pre-settlement native prairie remain.  Prairie restoration provides erosion control and wildlife habitat and is gaining popularity in Wisconsin partly because natural prairies are aesthetically pleasing.  However, prairie restoration also has the potential to sequester atmospheric carbon (C) to the soil.  Soil C content in the top 1 m and bulk density in the top 10 cm were measured in a chronosequence of tallgrass prairies at a fine-textured site near Arlington, WI (ARL) and a coarse-textured site at the International Crane Foundation (ICF) near Baraboo, WI to evaluate the impact of prairie restoration on C sequestration.  Soil textural differences between the sites contributed to significant differences in soil C content and the potential to sequester C to the soil.  Soil C content in the top 25 cm was significantly positively correlated to time elapsed since last disturbance at the ARL site (r = 0.72, p-value = 0.03), but not at the ICF site.  Bulk density was inversely related to time elapsed since last disturbance at the ARL site (r = -0.53) suggesting that soil structure improved with time, but no relationship was found at the ICF site.  The rates of C sequestration were generally smaller for the sandy than the silt loam soils studied and on average the silt loam soil sequestered more C.  Total C sequestered was positively related, while C sequestration rate was inversely related, to time since last disturbance at the ICF site, but both were inversely related at the ARL site.  Prairie restoration increased the potential for C sequestration in coarse- and fine-textured soils compared to nearby agricultural soils.