Tallgrass prairie is one of the most vulnerable ecosystems in North America due to the widespread conversion of land to agriculture. The many ecosystem services provided by tallgrass prairie, including erosion control, provision of habitat for numerous invertebrate and vertebrate species, or soil carbon sequestration, are jeopardized with the land use conversion of this once widespread ecosystem. Recently, prairie restoration has become a more common practice, thereby providing an opportunity to restore the ecosystem and its ecosystem services. Agricultural use of former prairie land has resulted in the loss of up to 60% of soil carbon stocks, and it is expected that prairie restoration can recover soil C stocks over multiple decades or centuries. However, the recovery rate as a function of land use history is not known. Here we investigate soil carbon stock dynamics in six land use types: (1) row crop agriculture, (2) pasture, (3) restored prairie (from row crop and from pasture), (4) remnant prairie, (5) old fields (unmanaged land) and (6) recently converted to cow pasture (“newly planted”). Soil cores were extracted in 2007 and again in 2018 in 40-m transects from these land use types at Midewin National Tallgrass Prairie.
Results/Conclusions
Soil cores collected in 2007 indicate both soil carbon (P = 0.004) and nitrogen (P = 0.01) differ with respect to land use history. Row crop lands had lower carbon stocks than all other land uses. Carbon stocks in newly planted pastures, restored prairies, and pastures did not differ from each other; furthermore, each contained about 1.5 times the carbon stocks as row crop lands. Old fields contained larger carbon stocks than row crops, newly planted pastures, restored prairie, and pastures, but less than remnant prairie. Results for nitrogen stocks were similar except that old fields did not differ from remnant prairie. In 2007, all sampled restored prairie sites were restored within 10 years prior to sampling. The 2018 soil samples represent an additional 11 years of soil development for these sites and also encompass recent prairie restoration conversions from pastures and row crops that occurred within the 2007-2018 period.