Calibration and Application of Mid-Infrared DRIFT Spectroscopy for the Analysis of Soil Organic Carbon for different Soil Types and Land Uses in NSW

Abstract

Soil organic carbon is a key indicator of soil condition and health and has attracted considerable research attention due to its potential role in carbon cycling and climate change. This study examined the calibration and application of mid-infrared DRIFT spectroscopy for the analysis of soil total organic carbon (TOC), with the intention of providing the foundation of a calibration model for the State of NSW. The calibration model is intended for use by the Office of Environment and Heritage (OEH) as a cost effective alternative to conventional dry combustion analysis of TOC for the purposes soil condition monitoring. In developing the basis for a State-wide calibration model, a series of individual Soil Monitoring Units (SMUs) and land use calibration models were constructed and compared with all-inclusive global calibration models to estimate and predict TOC. The calibration models were built using 8 SMUs representing distinct soil types and environmental conditions from the NSW State-wide Land and Soil Condition Monitoring, Evaluation and Reporting (MER) program initiated in 2008. The selected SMUs provided a range of different land uses and, where possible, 3 replicates of each land use; cultivation, native pasture and woodland. Soil Monitoring Unit datasets for the soil depths 0-50 and 50-100 mm were used to provide the spectral data and laboratory TOC results.