Soil health and root‐zone enrichment characteristics between paired grassland and cropland fields in the southeastern United States

Abstract

BackgroundSoil organic C and N data from privately managed pastures in the southeastern United States are relatively scant.MethodsA paired‐farm approach was deployed to determine how a variety of soil health parameters related to nutrient and water cycling might be altered under grazed, botanically diverse perennial pastures compared with annual monoculture croplands in three Major Land Resource Areas of the southeastern United States.ResultsSoil stability index averaged 0.64 and 0.91 mm mm−1 under cropland and grazed pasture, respectively, suggesting that pastures had a more stable soil surface that was resistant to erosion and allowed rapid water infiltration. Surface‐soil organic C and N fractions (i.e., total, particulate, and mineralizable fractions at 0–10 cm depth) were greater under pasture than under cropland. Across locations, root‐zone enrichments (0–30 cm depth) of organic C and N fractions were greater under pasture than under cropland. Within locations, root‐zone enrichment of total soil N was greater (p < 0.05) under pasture than under cropland in the Blue Ridge (2.87 vs. 1.10 Mg N ha−1, respectively) and the Piedmont (2.80 vs. 2.10 Mg N ha−1), but not in the Blackland Prairie (2.40 vs. 2.12 Mg N ha−1).ConclusionsThis study provides evidence that rotationally grazed, perennial grasslands can store more soil organic C and N and improve soil surface stability conditions compared with neighboring croplands producing commodity feed grains for feedlot finishing.

Introduction to the XXV International Grassland Congress virtual special issue

“…In a grassland ecology thematic session, grasslands exemplified the delivery of ecosystem services, including the capacity to store large reservoirs of soil organic carbon. One paper in this special section synthesized available literature on soil organic carbon changes with long-term grassland management in the southeastern United States (Silveira et al, 2024) and another paper presented new results of an unique calculation method to separate pedogenic from management-controlled soil organic carbon and nitrogen changes with long-term pasture management (Franzluebbers et al, 2023). In a grazing intensity experiment, the hypothesis that patches will lead to greater spatial variability in belowground biomass and soil organic carbon stocks was not validated (Komainda et al, 2023).…”