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

ABSTRACT

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.

KEYWORDS:

• Grassland
• greenhouse gases
• labile carbon
• recalcitrant carbon
• soil carbon

Funding

This study was funded by USDA-CSREES, Evans-Allen #0208180, in Lincoln University, Missouri, USA.

Additional information

Funding

This study was funded by USDA-CSREES, Evans-Allen #0208180, in Lincoln University, Missouri, USA.