Loss-On-Ignition Estimates for Soil Organic Carbon in Great Lakes Freshwater Coastal Wetlands

Abstract

Soil organic carbon (SOC) is an important component of freshwater wetlands that may be used to quantify ecosystem services and prioritize conservation efforts. Measuring SOC directly via elemental analysis is often time and cost-prohibitive. Loss-on-ignition (LOI) is a rapid and low-cost method for determining soil organic matter; however, LOI data must be converted to SOC data using a soil type-specific regression model and no models currently exist for freshwater coastal wetlands. To address this gap, we performed regression analyses that convert percent organic matter measured from LOI to SOC for freshwater coastal wetlands in the southern basin of Lake Michigan. Analyses across 6 Lake Michigan wetlands provide a regression model capable of estimating SOC within ±3.5% uncertainty (r2 = 0.757), a threshold useful for wetland management and large-scale soil surveys. Future research should explore the LOI-SOC relationship at other freshwater coastal wetlands – to investigate whether the correlation values found here are typical of these systems and to refine our regression model using data from disparate freshwater locales.