Long-term pasture management impacts on eolian sand soils in the southern mixed-grass prairie

Abstract Mixed grass pastures which occupy the eolian sand dunes of the southern Great Plains provide stabilizing soil cover, soil carbon (C) storage, and are a critical resource for livestock production. Large areas of dunes cover the American Great Plains, were active 700–1000 years ago during periods of frequent drought and have the potential to reactivate under forecasted climate scenarios and poor management. This study determined the soil age and development of eolian sandy soils and evaluated long-term grazing of native and improved pasture on root carbon, soil organic C (SOC), stable isotopes of soil fractions, and other soil properties. Pasture treatments included grazed and ungrazed (50 + yrs), improved pastures (28–50 yrs), and winter wheat (Triticum aestivum) or go-back grass (for 28–30yrs). Improved pasture grass species included both native (switchgrass (Panicum virgatum L.), and sand bluestem (Andropogon hallii Hack.) and non-native (weeping lovegrass (Eragrostis curvula (Schrad.) Nees)), and caucasian bluestem (Bothriochloa bladhii (Retz.) S.T. Blake) species. The Eda soil age was very recent and ranged from present at the surface to