Think outside the plots: Perimeter measurements and spatial modeling mitigate confounding in a 145‐year experiment
Abstract Long‐term experiments (LTEs) offer unique insights into the effects of agricultural practices on soil organic carbon (SOC). However, early LTEs commonly lack treatment randomization, replication, and initial measurements of SOC. This creates a potential problem of unmeasured confounding. We...
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| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
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Wiley
2025-06-01
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| Series: | Agricultural & Environmental Letters |
| Online Access: | https://doi.org/10.1002/ael2.70020 |
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| _version_ | 1849682917739986944 |
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| author | Eric Potash Yuhei Nakayama Michael Douglass Guadalupe Gonzalez Andrew J. Margenot |
| author_facet | Eric Potash Yuhei Nakayama Michael Douglass Guadalupe Gonzalez Andrew J. Margenot |
| author_sort | Eric Potash |
| collection | DOAJ |
| description | Abstract Long‐term experiments (LTEs) offer unique insights into the effects of agricultural practices on soil organic carbon (SOC). However, early LTEs commonly lack treatment randomization, replication, and initial measurements of SOC. This creates a potential problem of unmeasured confounding. We address this problem using the Morrow Plots (established 1876) as a case study. We start with a standard mixed effects model of SOC and add (i) a spatial kriging component and (ii) SOC measurements in the sod perimeter of the experiment as an additional treatment level. We find that much of the observed SOC variation between treatments after 145 years is not due to treatments but other factors (e.g. initial SOC), attenuating treatment effects by about 50%. Our study demonstrates that creative measurement and innovative modeling can mitigate some deficiencies in early LTEs. However, our improved estimates still have limited precision, suggesting the importance of careful design and measurement in the first place. |
| format | Article |
| id | doaj-art-e5af961f49ad453e9480d73d446fc416 |
| institution | DOAJ |
| issn | 2471-9625 |
| language | English |
| publishDate | 2025-06-01 |
| publisher | Wiley |
| record_format | Article |
| series | Agricultural & Environmental Letters |
| spelling | doaj-art-e5af961f49ad453e9480d73d446fc4162025-08-20T03:24:02ZengWileyAgricultural & Environmental Letters2471-96252025-06-01101n/an/a10.1002/ael2.70020Think outside the plots: Perimeter measurements and spatial modeling mitigate confounding in a 145‐year experimentEric Potash0Yuhei Nakayama1Michael Douglass2Guadalupe Gonzalez3Andrew J. Margenot4Agroecosystem Sustainability Center, Institute for Sustainability, Energy, and Environment University of Illinois Urbana‐Champaign Urbana Illinois USADepartment of Crop Sciences, College of Agricultural, Consumer and Environmental Sciences University of Illinois Urbana Champaign Urbana Illinois USADepartment of Crop Sciences, College of Agricultural, Consumer and Environmental Sciences University of Illinois Urbana Champaign Urbana Illinois USAAgroecosystem Sustainability Center, Institute for Sustainability, Energy, and Environment University of Illinois Urbana‐Champaign Urbana Illinois USAAgroecosystem Sustainability Center, Institute for Sustainability, Energy, and Environment University of Illinois Urbana‐Champaign Urbana Illinois USAAbstract Long‐term experiments (LTEs) offer unique insights into the effects of agricultural practices on soil organic carbon (SOC). However, early LTEs commonly lack treatment randomization, replication, and initial measurements of SOC. This creates a potential problem of unmeasured confounding. We address this problem using the Morrow Plots (established 1876) as a case study. We start with a standard mixed effects model of SOC and add (i) a spatial kriging component and (ii) SOC measurements in the sod perimeter of the experiment as an additional treatment level. We find that much of the observed SOC variation between treatments after 145 years is not due to treatments but other factors (e.g. initial SOC), attenuating treatment effects by about 50%. Our study demonstrates that creative measurement and innovative modeling can mitigate some deficiencies in early LTEs. However, our improved estimates still have limited precision, suggesting the importance of careful design and measurement in the first place.https://doi.org/10.1002/ael2.70020 |
| spellingShingle | Eric Potash Yuhei Nakayama Michael Douglass Guadalupe Gonzalez Andrew J. Margenot Think outside the plots: Perimeter measurements and spatial modeling mitigate confounding in a 145‐year experiment Agricultural & Environmental Letters |
| title | Think outside the plots: Perimeter measurements and spatial modeling mitigate confounding in a 145‐year experiment |
| title_full | Think outside the plots: Perimeter measurements and spatial modeling mitigate confounding in a 145‐year experiment |
| title_fullStr | Think outside the plots: Perimeter measurements and spatial modeling mitigate confounding in a 145‐year experiment |
| title_full_unstemmed | Think outside the plots: Perimeter measurements and spatial modeling mitigate confounding in a 145‐year experiment |
| title_short | Think outside the plots: Perimeter measurements and spatial modeling mitigate confounding in a 145‐year experiment |
| title_sort | think outside the plots perimeter measurements and spatial modeling mitigate confounding in a 145 year experiment |
| url | https://doi.org/10.1002/ael2.70020 |
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