Using a decade-long in-field incubation, we traced how plant litter and pyrogenic inputs contribute to soil organic matter fractions in native grassland. Isotopic labeling revealed that mineral-associated organic matter (MAOM) forms rapidly from soluble litter inputs and remains remarkably stable over time—largely independent of particulate dynamics. This work clarifies how distinct SOM fractions form and persist under real-world variability, offering insight into the temporal dynamics of soil carbon stabilization.

Authors:

Sam J. Leuthold, Jennifer L. Soong, Rebecca J. Even, and M. Francesca Cotrufo

Journal: Nature Geoscience, 2025

Cited 0 times

Soil organic matter drives cropland biogeochemistry in a myriad of ways. Here we asked if SOM fractions, like POM and MAOM, could help us to understand why areas of a field are stable in their yields from year to year. We identified a complex feedback loop, with high productivity areas accumulating POM due to interactions between weather, topography, and management.

Authors:

Sam J. Leuthold, Jocelyn M. Lavllee, Bruno Basso, William F. Brinton, and M. Francesca Cotrufo

Journal: SOIL, 2024

Cited 0 times

We isolate physical SOM fractions through a variety of methods. While the resulting fractions often share a conceptual definition, here, using a combination of chemical, isotopic, and spectral evidence, we show that there are important distinctions among the various procedural definitions, and that nuance is needed to understand what we’re isolating.

Authors:

Sam J. Leuthold, Jocelyn M. Lavallee, Michelle L. Haddix, and M. Francesca Cotrufo

Journal: Geoderma, 2024

Cited 12 times

The diversity-stability relationship is a deeply entrenched paradigm in ecological sciences. Previous work has shown that at the national level, this pattern extends to crop production. Here we ask, “At the sub-national level, does this relationship hold?” and find that responses diverge depending on whether you’re looking at the production of dollars or of calories.

Authors:

Avery W. Driscoll, Sam J. Leuthold,, Eunkyoung Choi, Samantha M. Clark, Daniel M. Cleveland, Mary Dixon, Marian Hsieh, Jan Sitterson, and Nathaniel D. Mueller

Journal: Environmental Research Letters, 2022

Cited 8 times

Establishing robust methods of separating soil organic matter into physical fractions (e.g., particulate and mineral associated organic matter) is critical to fostering useful syntheses and collaborations. Here we discuss methods of physical soil organic matter fractionation, dispersion, and analysis, and offer examples of protocols employed in both our lab and across the field.

Authors:

Sam J. Leuthold, Michelle L. Haddix, Jocelyn M. Lavallee, and M. Francesca Cotrufo

Journal: Encyclopedia of Soils in the Environment, 2022

Cited 28 times

Nitrous oxide is a potent greenhouse gas, often associated with agricultural systems. In this work, we used stable N, H, and O isotopes combined with mass balance analysis to show that a substantial amount of denitrification occurs from soils during fallow periods. This flux represents a significant loss of soil N, but up till now has been under-counted, with important implications for climate change.

Authors:

Adam W. Sigler, Stephanie A. Ewing, Scott D. Wankel, Clain A. Jones, Sam J. Leuthold,, E.N. Jack Brookshire, and Robert A. Payn

Journal: Biogeochemistry, 2022

Cited 12 times

In areas with complex topography, landscape position can be a major driver of cropping system performance. Here we review the literature to understand how that relationship is mediated by annual weather, finding that for corn, correlations between yield and elevation or slope became more positive as precipitation increased, however, the opposite was true for soybeans.

Authors:

Sam J. Leuthold, Ole Wendroth, Montserrat Salmerón, and Hanna Poffenbarger

Journal: Field Crops Research, 2022

Cited 13 times

Rolling hill landscapes engender increased variability in soil ecosystems, with differences in everything from soil temperature to crop productivity. Here we examined whether landscape position affects the decomposition rate of cover crop residue in two fields. We found significant differences in soil water status and temperature, but limited influence on decomposition.

Authors:

Sam J. Leuthold, Dan Quinn, Fernando Miguez, Ole Wendroth, Montserrat Salmerón, and Hanna Poffenbarger

Journal: Agriculture, Ecosystems, and Environment, 2021

Cited 13 times

Cover crops provide a number of benefits, one of which is decreasing the evaporative loss of water from the soil surface. Here we use cropping system models to investigate the impact of this increased water on yield stability over a 30 year period. We found that cover crops increased the amount of water available to crops during critical time, increasing yields and decreasing overall variability.

Authors:

Sam J. Leuthold, Ole Wendroth, Montserrat Salmerón, and Hanna J. Poffenbarger

Journal: Field Crops Research, 2021

Cited 15 times

In order to maximize the benefits of cover crops, science-based management recommendations are required. In this work, we examined the effects of fungicide, fertilizer, and termination timing on corn yields following a rye cover crop. We found that earlier termination improved corn yields, and that increasing inputs likely cannot alleviate stand loss in late-terminated systems.

Authors:

Dan J. Quinn, Hanna J. Poffenbarger, Sam J. Leuthold , and Chad D. Lee

Journal: Agronomy Journal, 2021

Cited 11 times

The first work I ever published. Here we used stable water isotopes to understand the seasonal differences in stream flow generation in a mountain watershed. We found complex patterns of intermittent connection between stream and soils during winter months, pushing back on the assumption that winter stream flow is synonymous with base flow.

Authors:

Sam J. Leuthold, Stephanie A. Ewing, Robert A. Payn, Florence R. Miller, and Stephen G. Custer

Journal: Hydrological Processes, 2021

Cited 9 times

Understanding where water is sourced from is critical to creating robust management strategies for future climates. In this work, we used geochemcial isotopic tracers to understand how water made it into the stream. The results show distinct contributions of different groundwater sources to stream flow, and indicate seasonal variability in stream flow generation sources.

Authors:

Florence R. Miller, Stephanie A. Ewing, Robert A. Payn, James B. Paces, Sam J. Leuthold, and Stephen G. Custer

Journal: Journal of Hydrology, 2020