Announcements

ISMC/ GEWEX Water Initiative (SoilWat) Workshop at Reading 

The International Soil Modelling Consortium (ISMC) Soil and GEWEX Water Initiative (SoilWat) jointly organized a 3 days workshop at Reading UK to bring together two research communities to improve the representation of soil and subsurface processes in weather and climate models. The subsurface modeling community, broadly represented ISMC, and the climate modeling community, represented by GEWEX, e.g. via its GLASS (Global Land Atmosphere Systems Study) panel, worked together to identify the most pressing challenges related to this effort and ways forward.

The ISMC – GEWEX SoilWat meeting 2025 serves as a continuation of the first first GEWEX SoilWat Initiative Planning Workshop held in Leipzig, Germany, in June 2016. The 2025 workshop aimed to assess achievements and identify research gaps since the last meeting. The main objective were to write a paper that will outline a roadmap, identifying the next frontiers and challenges in this field, and how collaboration can address these. This is especially important since significant developments have been taken place within the climate and soil modeling communities in recent years, in particular those relating to Machine Learning, Digital Twins, and high-resolution Earth System modeling.

Participants of the ISMC/ GEWEX Water Initiative (SoilWat) Workshop at Reading 

Travel grant for the 2nd International Summer school Advanced Soil Physics: Soil-Plant-Water Flow awarded to Diego Armando Fernandez Ibarra

Diego Armando Fernandez Ibarra holds a degree in Animal Science from the National University of the Centre of Peru (UNCP) in Junín. He is currently pursuing a master’s degree at the Soil Physics Laboratory of the Centre for Nuclear Energy in Agriculture (CENA), University of São Paulo (USP), Brazil. His academic journey includes volunteer work and internships with research groups and the National Institute of Agricultural Innovation (INIA) in Peru, where he gained hands-on experience in field planning and operations in high altitude Andean ecosystems, along with skills in remote sensing and multispectral image analysis. In 2019, he participated in a student exchange program at USP, contributing to fieldwork and activities at the Soil Physics Laboratory of the Luiz de Queiroz College of Agriculture. His current research focuses on the hydrological characterization of soils and the calibration of agro-hydrological models, particularly in the context of the Andean ecosystem in Peru.

Motivation of application for the grant 

During his undergraduate studies, he was drawn to soil physics due to its potential and the lack of research in this field within the Andes. In his master’s program, he came to understand that soil physics involves not only the characterization of soil properties but also their interpretation through modelling based on physical processes. This realization led him to focus on hydrological modelling. He learned about the summer school from former lab colleagues who attended the first edition in 2022, and their enthusiasm strongly motivated him to apply. His current research involves calibrating the agro-hydrological model SWAP for maize crops in the Mantaro Valley (Peru), with the goal of simulating extreme climate scenarios related to El Niño and climate change. The theoretical and practical knowledge he hopes to gain, along with the opportunity to engage with professors and fellow students in an international setting, will be invaluable not only for advancing his current research but also for supporting his long-term goal of contributing to scientific knowledge in this field — particularly in his home country. 

Special Issue in SOIL on Advances in dynamic soil modelling across scales open for submission

This special issue (SI) invites papers that study soil dynamics using numerical and statistical models. The focus will be on the development of model-based representations, or digital twins, of soil systems to study soil processes, dynamics, and functions from the pore to the landscape scale and from diurnal dynamics to millennial evolution. By bringing together modellers and models that work on different spatiotemporal scales, we aim at synergies between soil hydrology, soil physics, soil geography, and soil ecology to develop holistic models that consider soils and their functions as dynamic systems. This SI is an initiative of the International Soil Modeling Consortium and the 3-4D Soil models working group, part of the German Soil Science Society. Further details on the SI and submission can be found here. Submission is still open.

Featured Paper

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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. Submission can be done here. 

HESS Opinions: Towards a common vision for the future of hydrological observatories

The Unsolved Problems in Hydrology (UPH) initiative has emphasized the need to establish networks of multi-decadal hydrological observatories to gain a deep understanding of the complex hydrologic processes occurring within diverse environmental conditions. The already existing monitoring infrastructures have provided an enormous amount of hydrometeorological data, facilitating detailed insights into the causal mechanisms of hydrological processes, the testing of scientific theories and hypotheses, and the revelation of the physical laws governing catchment behavior. Yet, hydrological monitoring programs have often produced limited outcomes due to the intermittent availability of financial resources and the substantial efforts required to operate observatories and conduct comparative studies to advance previous findings. Recently, some initiatives have emerged that aim to coordinate data acquisition and hypothesis testing to facilitate an efficient cross-site synthesis of findings. To this end, a common vision and practical data management solutions need to be developed. This opinion paper provocatively discusses two potential endmembers of a future hydrological observatory (HO) network based on a given hypothesized community budget: a comprehensive set of moderately instrumented observatories or, alternatively, a small number of highly instrumented supersites.

A network of moderately instrumented monitoring sites would provide a broad spatial coverage across the major pedoclimatic regions by supporting cross-site synthesis of the lumped hydrological response (e.g., rainfall–runoff relationship, Budyko analysis) across diverse continental landscapes. However, the moderate instrumentation at each site may hamper an in-depth understanding of complex hydrological processes. In contrast, a small number of extensively instrumented research sites would enable community-based experiments in an unprecedented manner, thereby facilitating a deeper understanding of complex, non-linear processes modulated by scale-dependent feedback and multiscale spatiotemporal heterogeneity. Lumping resources has proven to be an effective strategy in other geosciences, e.g., research vessels in oceanography and drilling programs in geology. On the downside, a potential limitation of this approach is that a few catchments will not be representative of all pedoclimatic regions, necessitating the consideration of generalization issues.

A discussion on the relative merits and limitations of these two visions regarding HOs is presented to build consensus on the optimal path for the hydrological community to address the UPH in the coming decades. A final synthesis proposes the potential for integrating the two endmembers into a flexible management strategy. More information can be found here.

Dimensionality and scales of preferential flow in soils of Shale Hills hillslope simulated using HYDRUS

Preferential flow (PF) processes are governed by subsurface soil structures at various scales. Still, model validation and mechanistic understanding of PF are very lacking. We hypothesize that PF at hillslope and larger scales cannot be described and quantified when neglecting small-scaled spatially variable processes and simplifying the model dimensionality. The objective was to learn from comparing simulation results of multidimensional (1D, 2D, and 3D) and multiscale (pedon, catena, and catchment) modeling approaches with comprehensive datasets, and so as to evaluate PF simulations based on the Richards’ equation (solved by the HYDRUS software). Results showed limited alignment between 1D simulations and soil moisture data, mainly affected by vertical changes in porosity, permeability, and precipitation features. 2D and 3D simulations outperformed 1D models. 3D simulations provided satisfactory description of PF dynamics at the pedon scale, considering accurate representations of soil and bedrock structures for three dimensions (vertical, horizontal, and surrounding area). In 2D simulations at the pedon scale, models incorporating dual-porosity and anisotropy of soils yielded more accurate predictions of water dynamics than single-porosity and isotropic models. Furthermore, the application of 2D simulation at the catena scale identify PF pathways owing to the enhanced representation of the hydraulic connectivity between different locations along the slope. The results confirmed the significance of multidimensional and multiscale modeling approaches for PF simulations in hillslope hydrology. Considering the complexity and parameterization of 2D and 3D “bottom-up” physically based models in representing spatial variability within and between soil profiles and/or underlying bedrock geology, the results contribute to creating a modeling framework applicable to identify the PF processes and thus their implications in managing water resources. More information can be found here.

Featured Soil Modeler (Taiqi Lian)

Understanding carbon and water dynamics across landscapes with coupled ecohydrological-soil biogeochemical models

My name is Taiqi Lian, and I am currently pursuing a PhD at the École Polytechnique Fédérale de Lausanne (EPFL), Switzerland, under the supervision of Prof. Sara Bonetti in the Laboratory of Catchment Hydrology and Geomorphology. Before joining EPFL, I obtained my BSc in Water Conservancy and Hydropower Engineering from Wuhan University and a MSc in Environmental Engineering from ETH Zürich. As part of my PhD, I have worked on the development of a spatially distributed version of the process-based ecohydrological-biogeochemical model Tethys-Chloris-Biogeochemistry (T&C-BG), extending it to capture lateral fluxes and spatial heterogeneity within catchments (T&C-BG-2D). The goal of my research is to explore how topography and hydroclimatic variability shape soil carbon and nutrient cycling at multiple scales. We are also working on integrating biologically-promoted soil structure into the model to better represent its influence on biogeochemical processes at both plot and catchment scale.

- Please tell us briefly about yourself and your research interest.

I received my bachelor degree at Wuhan University in 2020, did my master in ETHz from 2020-2022, and started my PhD in EPFL since 02.2023. My research focuses on ecohydrological processes across scales, particularly the interactions between soil, vegetation, and water in response to landscape heterogeneity. I am broadly interested in soil erosion dynamics, landscape evolution, stochastic rainfall modeling, and the coupling of ecohydrological and soil biogeochemical models.

-  How did you first become interested in soil modelling and learn about ISMC?

One of the lab research foci is ecohydrological modelling, which naturally includes understanding and modeling soil-related processes. My supervisor, Prof. Sara Bonetti, is part of the ISMC and introduced me to it. I attended the SoilWat workshop in Reading in July 2025.

-Can you share with us your current research focus?

Currently, I am exploring how topography mediates soil biogeochemical responses to hydroclimatic fluctuations. This research aims to reveal the mechanisms and scaling relationships that govern carbon and nutrient dynamics in complex terrains. And I am also collaborating with an exchange PhD student and working to incorporate biologically-promoted soil structure into the T&C model to better understand how its effects propagate from plot to catchment scale.

- 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?

My research integrates coupled soil–vegetation–hydrology processes through a spatially distributed modeling framework, with a particular focus on how topography shapes water and carbon dynamics across scales. By explicitly accounting for spatial heterogeneity at the catchment scale, this work can contribute to the ISMC Science Panel’s efforts to better represent soil processes and variability in Earth System Models. In return, I hope to benefit from the panel’s interdisciplinary expertise in representing small-scale processes in models, as well as from shared data initiatives to test and calibrate the model across diverse environmental settings. This collaboration could also support the development of robust scaling approaches from plot to regional levels.

- 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?

I believe it is important for early-career researchers to engage in regular exchange with senior scientists in order to better understand the key challenges and future directions in the field. Opportunities to discuss open questions and emerging needs can help young researchers align their work with broader community goals. ISMC could support this by facilitating more interactive formats such as informal online presentations and formal in-person workshops, which would provide valuable platforms for feedback, inspiration, and collaboration.