Current Projects

Representing observational controls of decomposition in a process-based model 

Decomposition of plant material is a major global flux of carbon (C) that is thought to be controlled by climate, litter quality, and microbial community. Process-based models can represent these controls but may not correctly represent the importance of each of these drivers. We are parameterizing the microbially-explicit MIcrobial-MIneral Carbon Stabilization (MIMICS) model to correctly represent the relative importance of these drivers and will investigate this parameterization under global change.

Project partners: Will Wieder (CU), Peter Reich (UM), Derek Pierson (USFS), Mark Bradford, Fiona Jevon, Alex Polussa (Yale), Angela Oliverio (Syracuse), Stephen Wood (Nature Conservancy)

Soil organic matter frameworks

Soil organic matter (SOM) is central to ecosystem functions, including carbon storage, nutrient provisioning, and as a habitat for soil fauna. In past couple decades several influential conceptual frameworks have emerged that shape our understanding of SOM dynamics. In this review, we evaluate the empirical evidence and model representation of the ideas in these conceptual frameworks, as well as identify inconsistencies and future directions. This work is accepted for publication in the Journal of Geophysical Research-Biogeosciences.

Project partners: Will Wieder (CU), Peter Reich (UMich), Stuart Grandy, Serita Frey, Jessica Ernakovitch, Else Schlerman (UNH), Avni Malhotra (PNNL), Katerina Georgiou (LLNL), Erika Foster (Point Blue Conservation Science), Francesca Cotrufo (CSU)

Controls of soil C:N in theory, measurements, and models

The carbon-to-nitrogen ratio (C:N) of soil is a strong control of C and N cycling and their responses to global change. This ratio is largely conceptualized as emerging from plant and microbial inputs to soil organic matter, but many other plant-microbe-mineral interactions can contribute to soil C:N. To clarify the importance of these other controls we devised a new framework of soil C:N controls that likely underlie global patterns of soil C:N and will help improve our understanding of soil C:N responses to global change. This work was published in Soil Biology & Biochemistry.

Project partners: Will Wieder (CU), Peter Reich (UMich), Derek Pierson (USFS), Cory Cleveland, Emma Hauser (UMontana), Stuart Grandy, Hannah Holland-Moritz, Else Schlerman (UNH), Brooke Eastman (WVU), Katerina Georgiou (LLNL), Melannie Hartman (CSU), Emily Kyker-Snowman (Carbon Direct)

Previous Projects

Summarizing soil carbon responses to global environmental change

Soils hold the largest terrestrial store of C and thus, understanding their responses to global changes is crucial for predicting future C cycling. We used meta-analytical techniques to assess responses of two functionally different types of soil C; mineral associated organic C (MAOC) and particulate organic C (POC). This work is published in Science of the Total Environment.

Project partners: Francesca Cotrufo (CSU), Jocelyn Lavallee (CSU), & Catherine Stewart (USDA)

Soil organic matter under increased moisture availability

There is evidence to suggest that mineral-associated organic carbon (MAOC) may increase, while particulate organic carbon (POC) may decrease, under increased precipitation, leading to no change in total soil carbon but with important restructuring of this globally important carbon pool. To investigate this, we have sampled soils at a long-term irrigation experiment at an annually burned prairie in northeastern Kansas (Konza LTER) and measured soil organic matter dynamics and controls. This work was published in Soil Biology & Biochemistry.

Project partners: Francesca Cotrufo (CSU), John Blair (KSU), Alan Knapp (CSU), Michael Bird (JCU), Chao Liang (CAS)

Local nitrogen pollution in Rocky Mountain National Park (RMNP)

National parks are both places of exploration and places of conservation. Thus, it is important to understand how visitation affects park ecosystems. We are researching whether local N pollution from cars driving through the RMNP is affecting roadside ecosystems. We performed a proof-of-concept test in summer 2020 and are executed a complete project in summer 2021. This work was published in Water, Air, & Soil Pollution.

Project partners: Francesca Cotrufo (CSU) & Jill Baron (CSU)

Nutrient fertilization and soil organic matter stoichiometry and stability

Increased nutrient availability with global change will modify future biogeochemistry. To better understand this variation, we investigated the responses of soil C and N coupling and stability in soil organic matter fractions to nutrient fertilization across a global set of grasslands, in collaboration with the Nutrient Network. This work is published in Biogeochemistry.

Project partners: Francesca Cotrufo (CSU), Kaydee Barker (CSU), Nutrient Network scientists

Biochar affects on seasonal nitrogen cycling in alfalfa

Biochar, a sustainable soil amendement that enhances carbon sequestration, is likely to affect other aspects of soil. We investigated whether biochar addition could affect seasonal dynamics of N cycling in an alfalfa field in semiarid Colorado. Surprisingly, we found minimal biochar effects, but strong seasonal dynamics in N cycling. This research suggests limited ability of co-benefits of biochar in this system. We published this work in Soil Systems in 2019.

Project Partners: Francesca Cotrufo, Steven Fonte, and Joe von Fischer

Nitrogen fertilizer use and distribution as influenced by biochar

Biochar, a sustainable soil amendement that enhances carbon sequestration, is likely to affect other aspects of soil.  We assessed whether biochar diffeerntly affected soil and fertilizer N in a greenhouse study. We find that biochar had a stronger influence on fertilizer N but fairly limited effects overall. Details of this work are avaiable here.

Project partners: Francesca Cotrufo and Steven Fonte

Undergraduate research projects

Methane emissions and isotopic composition over a thaw gradient in a subarctic peatland. Mentor: Ruth Varner, UNH

Characterizing ice nucleating particles at the Western US Coast. Mentor: Sonia Kreidenweis, CSU

Plant and soil biogeochemistry over a bedrock gradient. Mentor: Julie Bryce, UNH