Soil Carbon and Nitrogen Fractions of a Grassland in Central Missouri, USA

Quantification of soil carbon (C) and nitrogen (N) fractions in grasslands is vital for estimating C sequestration and climate change studies. We quantified background soil total carbon (TOC) status, recalcitrant carbon (RC), acid hydrolysable labile carbon (AHC), hot-and cold-water extractable carbon (HWC and CWC, respectively) fractions in the grassland in this study. Soil C fractions were as follows: TOC (11,633 to 15,525 mg C kg(-1)); RC (11,500 to 15,357 mg C kg(-1)); AHC (132 to 168 mg C kg(-1)); HWC (57 to 70 mg C kg(-1)); and CWC (27 to 33 mg C kg(-1)). Labile C fractions contributed at most 1.2% to total C. Concentrations of total N ranged from 1072 to 1230 g N kg(-1). Recalcitrant C contributed higher amounts (>90%) to total C, indicating the incorporation of C into the stable C fraction. Carbon dioxide (CO2) and nitrous oxide (N2O) fluxes were not significantly correlated with total C.