Effects of two-century land use changes on soil iron crystallinity and accumulation in Southeastern Piedmont region, USA

摘要: Abstract To evaluate effects of land use changes on iron (Fe) crystallinity in mineral soil, this study quantified labile, short-range ordered and relatively crystalline pools upper soils old hardwood forests, cultivated agricultural fields, old-field pine a common trajectory land-use history the upland Southern Piedmont, USA. Particularly comparable forest but with varying erosion histories, we indexed their surface mineral-soil compared cycling (accretion floor soil horizons) variety different ecosystems. Our results indicate that: (i) sites three uses showed significantly higher than supporting hardwoods or formerly that have supported 50 years regeneration; (ii) five selected increasing elevated erosion; (iii) accretion organic horizons are ubiquitous across forests non-needle materials needles. Given continued more technologically intensive plowing Piedmont region, attribute agriculture activities accelerate loss complexed Fe resulted oxide at depth exposed to surface. Also, large input during regrowth for decades reestablished reactivity significant oxides profiles suggesting major influence biological mediating transformation carbon compounds particularly horizon. This suggests (agriculture reforestation) play profound role transforming its interaction matter decomposition biologically active litter layers. It remains unclear how (via animal microbes) these layers driven biogeochemical redistribution terrestrial