Soil type and water level treatments influence peatland CO2 efflux in simulated restoration

Abstract

Peatlands are characterized by accumulation of organic matter primarily in response to soil anoxia and soil saturation. In the Cavalier Wildlife Management Area (CWMA) of southeastern Virginia, weirs were installed within ditches in an effort to restore peatlands. The purpose of this research was to determine the water levels that restore soil respiration functions and encourage carbon dioxide (CO2) sequestration. Core microcosms of two soil types (histosol and ultisol) were collected and established in the laboratory with differing water level treatments with simulated depth to water table. Incubations continued for 1 month and CO2 emission rates of the soil cores were measured twice per week using a portable photosynthesis instrument. Results from a mixed linear model and Tukey post-hoc tests demonstrated water level treatments were inversely correlated to CO2 emissions regardless of soil type and that the ultisol soil type exhibited lower percent volumetric water content and higher CO2 emissions overall. This suggests that higher water tables suppress CO2 emissions and can increase carbon sequestration, and that natural resource managers should evaluate soil types when establishing restoration and carbon sequestration goals, as soil types have differing responses to hydrologic restoration.