Optimal Sampling and Assay for Estimating Soil Organic Carbon
Open Access
- 1 January 2021
- journal article
- research article
- Published by Scientific Research Publishing, Inc. in Open Journal of Soil Science
- Vol. 11 (02), 93-121
- https://doi.org/10.4236/ojss.2021.112006
Abstract
The world needs around 150 Pg of negative carbon emissions to mitigate climate change. Global soils may provide a stable, sizeable reservoir to help achieve this goal by sequestering atmospheric carbon dioxide as soil organic carbon (SOC). In turn, SOC can support healthy soils and provide a multitude of ecosystem benefits. To support SOC sequestration, researchers and policy makers must be able to precisely measure the amount of SOC in a given plot of land. SOC measurement is typically accomplished by taking soil cores selected at random from the plot under study, mixing (compositing) some of them together, and analyzing (assaying) the composited samples in a laboratory. Compositing reduces assay costs, which can be substantial. Taking samples is also costly. Given uncertainties and costs in both sampling and assay along with a desired estimation precision, there is an optimal composite size that will minimize the budget required to achieve that precision. Conversely, given a fixed budget, there is a composite size that minimizes uncertainty. In this paper, we describe and formalize sampling and assay for SOC and derive the optima for three commonly used assay methods: dry combustion in an elemental analyzer, loss-on-ignition, and mid-infrared spectroscopy. We demonstrate the utility of this approach using data from a soil survey conducted in California. We give recommendations for practice and provide software to implement our framework.Keywords
This publication has 26 references indexed in Scilit:
- An equivalent soil mass procedure for monitoring soil organic carbon in multiple soil layersEuropean Journal of Soil Science, 2013
- Some considerations on aggregate sample supports for soil inventory and monitoringEuropean Journal of Soil Science, 2012
- Optical sensing and chemometric analysis of soil organic carbon – a cost effective alternative to conventional laboratory methods?Soil Use and Management, 2011
- Whole‐Profile Soil Carbon Stocks: The Danger of Assuming Too Much from Analyses of Too LittleSoil Science Society of America Journal, 2011
- Near- versus mid-infrared diffuse reflectance spectroscopy for soil analysis emphasizing carbon and laboratory versus on-site analysis: Where are we and what needs to be done?Geoderma, 2010
- Evaluation of Different Soil Carbon Determination MethodsCritical Reviews in Plant Sciences, 2009
- Capability of Loss‐on‐Ignition as a Predictor of Total Organic Carbon in Non‐Calcareous Forest SoilsCommunications in Soil Science and Plant Analysis, 2005
- Spatially Balanced Sampling of Natural ResourcesJournal of the American Statistical Association, 2004
- Constrained optimisation of soil sampling for minimisation of the kriging varianceGeoderma, 1999
- An Investigation of Some Estimators of Variance for Systematic SamplingJournal of the American Statistical Association, 1984