ISMC News 15 November 2022
Announcements + Featured Paper + Featured Soil Modeller
Announcements
ISMC Session at EGU
A session on “Soil Hydrology in Earth System Models and its Parameterisation” (HS8.3.6) has been submitted on behalf of the ISMC working group Pedotransfer Functions. Conveners are Tobias Weber, Sara Bonetti, Surya Gupta, Lutz Weihermüller, and Toby Marthews. All of you are welcome to submit an abstract to this session. More info can be found here
BONARES Conference 2023: Soil as a Sustainable Resource (15-17 May 2023, Berlin, Germany)
A sustainable bioeconomy requires integration of soil productivity with a wide range of other soil functions including nutrient cycling, carbon storage, water retention and filtering as well as being the habitat of a myriad of organisms and enabling their activities. The conference will bring together researchers from various disciplines related to soil and plant sciences and agronomy to discuss strategies towards a (multi)functionality of soil ecosystems taking also constraints of climate and global change into account. The conference aims at providing solutions for a sustainable soil management including climate change adaptation, which requires an understanding of soils at a systemic level and to assess their value in a socio-economic framework.
BONARES is looking forward to welcome interested scientists as well as stakeholders in the field of soil management for inspiring discussions.
The following topics will be presented at the conference:
1. Impact of agriculture and cropping systems on soil functions
2. Carbon and nutrient cycling in soils: Processes and interactions in a changing world
3. Soil biomes and multifunctionality of soils
4. Soil degradation and sustainable soil management in agricultural landscapes
5. Model-based prediction of the dynamics of soil functions
6. Using soil sensing technologies for soil mapping, modelling and decision making in agriculture
7. Soils as a key to climate change mitigation: private and public governance instruments to unlock the potential
8. Data challenges and solutions
More information can be found at www.bonares2023.de. Abstract submission deadline is January 10th, 2023
Featured Paper
Do you want your paper featured?
Please share your recent paper if you want to be featured in the ISMC newsletter. With your contributions, we will select one paper to be featured in every newsletter. Below is the link to google form https://forms.gle/Pfkc7cf5hw2U8cFu5
The extent to which soil hydraulics can explain ecohydrological separation
Field measurements of hydrologic tracers indicate varying magnitudes of geochemical separation between subsurface pore waters. The potential for conventional soil physics alone to explain isotopic differences between preferential flow and tightly-bound water remains unclear. Here, we explore physical drivers of isotopic separations using 650 different model configurations of soil, climate, and mobile/immobile soil-water domain characteristics, without confounding fractionation or plant uptake effects. We find simulations with coarser soils and less precipitation led to reduced separation between pore spaces and drainage. Amplified separations are found with larger immobile domains and, to a lesser extent, higher mobile-immobile transfer rates. Nonetheless, isotopic separations remained small (<4‰ for δ2H) across simulations, indicating that contrasting transport dynamics generate limited geochemical differences. Therefore, conventional soil physics alone are unlikely to explain large ecohydrological separations observed elsewhere, and further efforts aimed at reducing methodological artifacts, refining understanding of fractionation processes, and investigating new physiochemical mechanisms are needed.
https://doi.org/10.1038/s41467-022-34215-7
a Averaged downscaled flux-weighted precipitation δ2H isotope value with error bars denoting ±1 standard deviation from the ten input simulations as well as the daily input precipitation amount as blue bars. b Averaged time series of the ten simulated volumetric water contents of a single porosity soil (Bulk, solid black line), the mobile and immobile volumetric water contents for a soil with high immobile fractions (Hf(mo.) and Hf(im.) respectively, dark gray), and the mobile and immobile volumetric water contents for a soil with low immobile fractions (Lf(mo.) and Lf(im.) respectively, light gray), as well as the drainage from the column (thin green line). δ2H isotope ratios of the c mobile soil water domain, d immobile soil water domain, and e column drainage for the soils simulated with a single pore domain model (0f, black), high immobile fraction with high and low transfer rates (HfHω, red; HfLω, orange) and low immobile fractions with high and low transfer rates (LfHω, cyan; LfLω, blue). The input precipitation time series was repeated three times in series, with the final 100 days (days 200–300) displayed. Note: line styles are the same for c–e and the line for LfHω is behind LfLω in d and e.
Featured Soil Modeller
Debjani Sihi is an assistant professor in the Department of Environmental Sciences at Emory University (Atlanta, GA, USA). Before joining Emory, she had postdoctoral appointments at Oak Ridge National Laboratory (Oak Ridge, TN, USA) and University of Maryland Center for Environmental Science (Frostburg, MD, USA). She is a biogeochemist with a broad research interest in the role of microbial- and enzyme-mediated processes in soil organic matter decomposition and greenhouse gas emissions from natural and managed ecosystems. She uses biogeochemical models to evaluate the fate of soil (and ecosystem) carbon (and nutrient) in the face of climate change in systems ranging from the tropics and subtropics to temperate and sub-boreal ecosystems.
- Please tell us briefly about yourself and your research interest.
Debjani investigates how environmental constraints (e.g., soil water content, quantity and quality of substrates, nutrient contents) confound the temperature sensitivity of soil organic matter (de)stabilization under both laboratory and field conditions. Specifically, she integrates subsurface soil process measurements with surface chamber fluxes and landscape-scale fluxes to allow the scaling-up of process-based models and soil-flux measurements to the ecosystem scale using advanced statistical techniques (e.g., Bayesian methods) and high-performance computing. Using a novel integration of measurements and modeling of greenhouse gas fluxes, she demonstrated how representing soil microsite heterogeneity in biogeochemical models informed by Michaelis-Menten kinetics and microbial functional groups can improve predictions of soil greenhouse gas fluxes, which would otherwise be difficult to reproduce (e.g., net methane emissions from upland forest soils or simultaneous net methane oxidation and net nitrous oxide reduction from the same soil profile).
- How did you first become interested in soil modelling and learn about ISMC?
With degrees in soil and environmental sciences in her bachelor and master programs back in India, she learned how soil carbon-climate feedback is intricately linked with policies related to climate change, agriculture, and other land-use practices (forests, wetlands). While starting her PhD program at the University of Florida, she was given an opportunity to couple data generated from empirical studies with microbial models of soil organic carbon cycling. She quickly grabbed that with the hope that through her work on soil organic matter and greenhouse gas modeling she can contribute to improving belowground dynamics in ecosystem and Earth system models. While doing her postdoctoral work at the University of Maryland Center for Environmental Science, she first learned about the International Soil Modeling Consortium through a professional network and joined the first ISMC meeting in 2016 in Austin, Texas, USA. Since then, she has remained connected with the ISMC community and has been exploring collaborating opportunities on multiple occasions.
-Can you share with us your current research focus?
At Emory, she is currently leading an externally funded research program (supported by both federal agencies and private industry) on soil biogeochemistry. For her DOE-funded project (Environmental System Science program, ESS), she is predicting greenhouse gas dynamics in the Terrestrial-Aquatic Interfaces, TAIs (coastal and freshwater wetlands) by incorporating probability distributions (aka heterogeneity) of redox processes at soil microsites using a coupled modeling-experimental (ModEx) approach. For her NSF-funded project (Macrosystem Biology and NEON-Enabled Science program), we are upscaling ground-truth measurements of soil organic carbon to the continental scale by understanding emergent ecosystem properties and spatial representativeness analysis. Through another NSF-funded project, she is planning to improve understanding biophysical drivers of the methane source sink transition in northern forests. Leveraging industry funding from Valent USA and Valent Biosciences and the United State Department of Agriculture, she is also exploring the persistence of agricultural soil carbon sequestration through a microbial lens to evaluate the efficacy of different climate-smart practices in mitigating climate change impacts. She is relying on multi-institutional and multi-disciplinary collaborations for all these projects. More information can be found in her website (https://www.debjanisihi.com/).
- Please tell us briefly how your research could contribute to ISMC Science Panel’s activities? Or the other way around, how do you wish ISMC science panels help/support your research activities?
I am already exploring collaboration opportunities through ISMC working group activities. It is an immense pleasure to interact and work with soil modeling nerds around the world through this platform. For example, I am collaborating on an exciting manuscript led by Kathe Todd-Brown that aims to evaluate soil organic carbon sequestration potential. Also, I am enjoying participating in another newly-formed ISMC working group activity (Math of Soil, led by Kathe Todd-Brown, Martine Van der Ploeg, and Yijian Zeng). The ongoing webinar series is a great resource for modeling soil processes. I am looking forward to getting more engaged with related activities.
- What resources or skills would you recommend that early career members of ISMC should acquire? And how can ISMC help and support early career members in this regard?
One thing I tell my students and postdocs is that you need to keep yourself updated with what are the cutting-edge science questions the scientific community is asking and what are the state-of-the-art techniques and skills required to address those questions. Once you know the problem, you need to find your niche (and passion to solve the problem), but always keep your door open for collaborations. Adding technical skills (e.g., proficiency in commonly used programming languages, experience with version control, high-performance computing, cloud computing, data management, repositories for archiving data and code) to their toolbox will make early career members more competitive in the job market. A lot of open-source tutorials are out there that can help improve your technical skills. Luckily, our community is very welcoming and networks like ISMC can create opportunities for early career members to connect with experts in the field through mentoring and other networking opportunities.