Testing the feasibility of quantifying change in agricultural soil carbon stocks through empirical sampling
There is disagreement about the potential for regenerative management practices to sequester sufficient soil organic carbon (SOC) to help mitigate climate change. Measuring change in SOC stocks following practice adoption at the grain of farm fields, within the extent of regional agriculture, could...
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| Format: | Article |
| Language: | English |
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Elsevier
2023-12-01
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| Series: | Geoderma |
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| Online Access: | http://www.sciencedirect.com/science/article/pii/S0016706123003968 |
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| author | M.A. Bradford L. Eash A. Polussa F.V. Jevon S.E. Kuebbing W.A. Hammac S. Rosenzweig E.E. Oldfield |
| author_facet | M.A. Bradford L. Eash A. Polussa F.V. Jevon S.E. Kuebbing W.A. Hammac S. Rosenzweig E.E. Oldfield |
| author_sort | M.A. Bradford |
| collection | DOAJ |
| description | There is disagreement about the potential for regenerative management practices to sequester sufficient soil organic carbon (SOC) to help mitigate climate change. Measuring change in SOC stocks following practice adoption at the grain of farm fields, within the extent of regional agriculture, could help resolve this disagreement. Yet sampling demands to quantify change are considered infeasible primarily because within-field variation in stock sizes is thought to obscure accurate quantification of management effects on incremental SOC accrual. We evaluate this ‘infeasibility assumption’ using high-density (e.g., 0.1 ha sample–1), within-field, sampling data from 45 cropland fields inventoried for SOC. We explore how more typical within-field sampling densities, as well as field numbers and magnitude of simulated change in SOC stocks, impacts the ability to accurately quantify management effects on SOC change. We find that (1) stock change estimates for individual fields are inaccurate and variable, where marked losses and gains in SOC stocks are frequently estimated even when no change has occurred. Higher sampling densities (e.g., 1.2 versus 4.0 ha sample–1) narrow the range of estimated stock changes but inaccuracies remain large. (2) The accuracy of stock change estimates at the project level (i.e., multiple fields) were similarly sensitive to sampling density. In contrast to individual fields, however, higher sampling densities, as well as a greater number of fields (e.g., 30), generated robust and accurate, mean project-level estimates of carbon accrual, with ∼ 80 % of the estimates falling within 20 % of the simulated stock change. Yet such monitoring designs do not account for dynamic baselines, which necessitates measurement of stock changes in control, non-regenerative fields. We find (3) that higher sampling densities (e.g., 1.2 versus 4.0 ha sample–1), field numbers (e.g., 30 versus 10 pairs of fields), and magnitudes of simulated SOC stock change (+3 and +5 versus +1 Mg C ha−1 10 y–1) are then collectively required to make accurate estimates of management effects on stock change at the project level. The simulated effect sizes that could be consistently detected under these conditions included rates of SOC accrual considered achievable and meaningful for climate mitigation (e.g., 3 Mg C ha−1 10 y–1), with field numbers and sampling densities that are reasonable given current sampling methods. Our findings reveal the potential to use empirical approaches to accurately quantify, at project scales, SOC stock responses to practice change. We provide recommendations for data that government, farmer and corporate entities should measure and share to build confidence in the effects of regenerative practices, freeing the SOC debate from overreliance on theory and data collected at scales mismatched with agricultural management. |
| first_indexed | 2024-03-09T01:29:53Z |
| format | Article |
| id | doaj.art-f9151624b44549aaa1d922d84feda2ec |
| institution | Directory Open Access Journal |
| issn | 1872-6259 |
| language | English |
| last_indexed | 2024-03-09T01:29:53Z |
| publishDate | 2023-12-01 |
| publisher | Elsevier |
| record_format | Article |
| series | Geoderma |
| spelling | doaj.art-f9151624b44549aaa1d922d84feda2ec2023-12-10T06:13:40ZengElsevierGeoderma1872-62592023-12-01440116719Testing the feasibility of quantifying change in agricultural soil carbon stocks through empirical samplingM.A. Bradford0L. Eash1A. Polussa2F.V. Jevon3S.E. Kuebbing4W.A. Hammac5S. Rosenzweig6E.E. Oldfield7The Forest School, Yale School of the Environment, Yale University, 360 Prospect St., New Haven, CT 06511, USA; Yale School of the Environment, Yale University, 195 Prospect St., New Haven, CT 06511, USA; Yale Center for Natural Carbon Capture, Yale University, New Haven, CT 06511, USA; Corresponding author at: The Forest School, Yale School of the Environment, Yale University, 360 Prospect St., New Haven, CT 06511, USA.The Forest School, Yale School of the Environment, Yale University, 360 Prospect St., New Haven, CT 06511, USA; Yale Center for Natural Carbon Capture, Yale University, New Haven, CT 06511, USAYale School of the Environment, Yale University, 195 Prospect St., New Haven, CT 06511, USAYale School of the Environment, Yale University, 195 Prospect St., New Haven, CT 06511, USAThe Forest School, Yale School of the Environment, Yale University, 360 Prospect St., New Haven, CT 06511, USA; Yale Center for Natural Carbon Capture, Yale University, New Haven, CT 06511, USAEcosystem Services Market Consortium, 3426 Greentree Dr., Falls Church, VA 22041, USAGeneral Mills Inc., 1 General Mills Blvd, Golden Valley, MN 55426, USAEnvironmental Defense Fund, 1875 Connecticut Ave NW #600, Washington DC 20009, USAThere is disagreement about the potential for regenerative management practices to sequester sufficient soil organic carbon (SOC) to help mitigate climate change. Measuring change in SOC stocks following practice adoption at the grain of farm fields, within the extent of regional agriculture, could help resolve this disagreement. Yet sampling demands to quantify change are considered infeasible primarily because within-field variation in stock sizes is thought to obscure accurate quantification of management effects on incremental SOC accrual. We evaluate this ‘infeasibility assumption’ using high-density (e.g., 0.1 ha sample–1), within-field, sampling data from 45 cropland fields inventoried for SOC. We explore how more typical within-field sampling densities, as well as field numbers and magnitude of simulated change in SOC stocks, impacts the ability to accurately quantify management effects on SOC change. We find that (1) stock change estimates for individual fields are inaccurate and variable, where marked losses and gains in SOC stocks are frequently estimated even when no change has occurred. Higher sampling densities (e.g., 1.2 versus 4.0 ha sample–1) narrow the range of estimated stock changes but inaccuracies remain large. (2) The accuracy of stock change estimates at the project level (i.e., multiple fields) were similarly sensitive to sampling density. In contrast to individual fields, however, higher sampling densities, as well as a greater number of fields (e.g., 30), generated robust and accurate, mean project-level estimates of carbon accrual, with ∼ 80 % of the estimates falling within 20 % of the simulated stock change. Yet such monitoring designs do not account for dynamic baselines, which necessitates measurement of stock changes in control, non-regenerative fields. We find (3) that higher sampling densities (e.g., 1.2 versus 4.0 ha sample–1), field numbers (e.g., 30 versus 10 pairs of fields), and magnitudes of simulated SOC stock change (+3 and +5 versus +1 Mg C ha−1 10 y–1) are then collectively required to make accurate estimates of management effects on stock change at the project level. The simulated effect sizes that could be consistently detected under these conditions included rates of SOC accrual considered achievable and meaningful for climate mitigation (e.g., 3 Mg C ha−1 10 y–1), with field numbers and sampling densities that are reasonable given current sampling methods. Our findings reveal the potential to use empirical approaches to accurately quantify, at project scales, SOC stock responses to practice change. We provide recommendations for data that government, farmer and corporate entities should measure and share to build confidence in the effects of regenerative practices, freeing the SOC debate from overreliance on theory and data collected at scales mismatched with agricultural management.http://www.sciencedirect.com/science/article/pii/S0016706123003968Carbon creditsConservation agricultureMRV protocolsNatural experimentsScalingSoil carbon monitoring |
| spellingShingle | M.A. Bradford L. Eash A. Polussa F.V. Jevon S.E. Kuebbing W.A. Hammac S. Rosenzweig E.E. Oldfield Testing the feasibility of quantifying change in agricultural soil carbon stocks through empirical sampling Geoderma Carbon credits Conservation agriculture MRV protocols Natural experiments Scaling Soil carbon monitoring |
| title | Testing the feasibility of quantifying change in agricultural soil carbon stocks through empirical sampling |
| title_full | Testing the feasibility of quantifying change in agricultural soil carbon stocks through empirical sampling |
| title_fullStr | Testing the feasibility of quantifying change in agricultural soil carbon stocks through empirical sampling |
| title_full_unstemmed | Testing the feasibility of quantifying change in agricultural soil carbon stocks through empirical sampling |
| title_short | Testing the feasibility of quantifying change in agricultural soil carbon stocks through empirical sampling |
| title_sort | testing the feasibility of quantifying change in agricultural soil carbon stocks through empirical sampling |
| topic | Carbon credits Conservation agriculture MRV protocols Natural experiments Scaling Soil carbon monitoring |
| url | http://www.sciencedirect.com/science/article/pii/S0016706123003968 |
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