Article
Soil Science
Emmanuel Arthur, Hafeez Ur Rehman, Markus Tuller, Nastaran Pouladi, Trine Norgaard, Per Moldrup, Lis Wollesen de Jonge
Summary: This study proposes regression models that estimate the Atterberg limits and plasticity index based on hygroscopic water content at different relative humidity values. The results show that measuring water content at higher relative humidity levels provides more accurate estimates of the Atterberg limits. The models based on hygroscopic water content outperformed models based on clay content and organic carbon or CEC in estimating the Atterberg limits.
Article
Soil Science
Maria Knadel, Hafeez Ur Rehman, Nastaran Pouladi, Lis Wollesen de Jonge, Per Moldrup, Emmanuel Arthur
Summary: This study demonstrated the feasibility of using visible near-infrared spectroscopy as a fast and accurate alternative to conventional methods for determining Atterberg limits in soil samples. Support Vector Machines showed slightly better predictive ability compared to Partial Least Squares regression and Artificial Neural Networks. The newly developed pedotransfer functions provided slightly better estimations for Atterberg limits, indicating the great potential of vis-NIRS for reliable estimates in diverse soil samples.
Article
Energy & Fuels
Mengying Gao, Cong Mou, Yanyuxin Ou, Xing Wan, Jianwen Ding
Summary: A large number of mixed soils with different compositions exist in nature, and their physical parameters, especially the liquid limits, play a crucial role in determining their mechanical properties. The liquid limits of sand-clay mixtures are influenced by the types of original soils and the contents of each constituent. Researchers propose an empirical equation to predict the liquid limits of sand-clay mixtures based on the liquid limits of original clays and clay contents, and this method can be extended to predict the liquid limits of mixed soils with more types of original soils.
Article
Geosciences, Multidisciplinary
S. Stanchi, S. Negri, M. E. D'Amico, E. Raimondo, E. Bonifacio
Summary: Fragipan soil horizons are characterized by high bulk density and fine blind pores, impacting Atterberg limits; liquid limit is slightly higher, plastic limit is comparable, with longer pre-wetting time needed; Neural Networks indicate that texture and bulk density mainly influence the transition from plastic to liquid state.
Article
Chemistry, Multidisciplinary
Eyyub Karakan
Summary: This study aims to determine the undrained shear strength of remolded clay mixtures using Atterberg limit test results, and proposes a reliable solution. The results of experimental study show that shear strength is significantly affected by soil conditions, rather than dominant clay mineral.
APPLIED SCIENCES-BASEL
(2022)
Article
Chemistry, Physical
Jose Manuel Moreno-Maroto, Jacinto Alonso-Azcarate
Summary: This study thoroughly examined the suitability of the texture triangle developed by USDA for soil classification, analyzing a large number of soil samples from various countries. The evaluation revealed limitations in the USDA classification system, leading to a new proposal that integrates plastic and textural properties for more accurate soil classification.
APPLIED CLAY SCIENCE
(2022)
Article
Environmental Sciences
G. Kannan, B. C. O'Kelly, E. R. Sujatha
Summary: This paper investigates the effect of three biopolymers (chitin, chitosan, and NaCMC) on the consistency limits of low plasticity organic silt soil. The results show that the consistency limits increased with increasing dosage of biopolymer additives, with NaCMC having a more significant effect. The bridging effect of the additives improved soil strength properties, leading to a significant increase in liquid limit.
INTERNATIONAL JOURNAL OF ENVIRONMENTAL SCIENCE AND TECHNOLOGY
(2023)
Article
Computer Science, Artificial Intelligence
Xinhua Xue, Chubing Deng
Summary: This study presents seven gene expression programming (GEP) models for predicting the creep index of natural soft clays using different combinations of input variables. The proposed GEP models outperform conventional empirical models and machine learning models in terms of prediction performance, making them recommended for engineering practice.
Editorial Material
Engineering, Geological
Brendan C. O'Kelly, Jose Manuel Moreno-Maroto, Jacinto Alonso-Azcarate
Summary: The authors presented an extrusion-based technique for quantifying the workability of fine-grained soils, but the discussers argued that this method is not appropriate for determining the Atterberg plastic limit of different fine-grained soils. They also questioned the authors' use of a fixed calibrated workability value and suggested that the workability parameter may actually be an assessment of undrained shear strength.
GEOTECHNICAL TESTING JOURNAL
(2022)
Review
Engineering, Civil
Brendan C. O'Kelly
Summary: This discussion article provides commentary on consistency limits determinations for peats and peaty soils. The writer disagrees with the recommended conventional consistency limits tests for peat soils and suggests using a more useful suite of index tests to assess the geotechnical behaviors and properties of these materials.
KSCE JOURNAL OF CIVIL ENGINEERING
(2022)
Review
Chemistry, Physical
Amin Soltani, Mahdieh Azimi, Brendan C. O'Kelly
Summary: Among the various methods for estimating the plasticity index (PI), empirical correlations based on the linear shrinkage (LS) test are gaining attention. This study aims to assess the potential and limitations of LS-based correlations for PI estimation, and explore the use of LS as a proxy for PI in soil classification. Statistical analyses on a diverse database of 265 fine-grained soils demonstrated that LS can only provide a rough approximation of PI. However, a novel multivariable correlation involving LS and liquid limit (LL) showed promising results for soil classification.
APPLIED CLAY SCIENCE
(2023)
Review
Multidisciplinary Sciences
Lekan Olatayo Afolagboye, Abel Ojo Talabi, Olubunmi Oluwadare Owoyemi
Summary: The Casagrande plasticity chart is traditionally used to classify fine grain soils, but recent research has shown that the new plasticity chart developed by Polidori provides more accurate classification of lateritic soils. Polidori's plasticity chart results are predominantly in agreement with the main soil fractions or components of the soils.
Article
Multidisciplinary Sciences
Ahmed M. Ebid, Kennedy C. Onyelowe
Summary: This research presents an innovative constitutive model for undrained clay based on its consistency limits and water content, which can simulate the nonlinear behavior of clay and study the impact of seepage on shallow foundation.
Article
Multidisciplinary Sciences
Tugba Eskisar
Summary: A series of one-dimensional consolidation tests were conducted on reconstituted soil mixtures with different mineral compositions to study the compression behavior and establish a link between liquid limit and clay mineral ratio. New equations and a triangular chart were proposed to estimate the compression indexes of reconstituted soils, and a simple way to determine the virgin compression lines of reconstituted specimens was described.
ARABIAN JOURNAL FOR SCIENCE AND ENGINEERING
(2021)
Article
Engineering, Geological
Jose Manuel Moreno-Maroto
Summary: This paper introduces a new grooving tool that allows obtaining grooves of equal dimensions in low-plasticity soils as those obtained with the flat tool in cohesive soils, reducing uncertainty in the results.
GEOTECHNICAL TESTING JOURNAL
(2022)
Article
Soil Science
Elham Farahani, Hojat Emami, Amir Fotovat, Reza Khorassani, Thomas Keller
Article
Agronomy
Rene Reiser, Viktor Stadelmann, Peter Weisskopf, Lina Grahm, Thomas Keller
JOURNAL OF PLANT NUTRITION AND SOIL SCIENCE
(2020)
Article
Soil Science
Per Schjonning, Mathieu Lamande, Thomas Keller, Rodrigo Labouriau
SOIL & TILLAGE RESEARCH
(2020)
Article
Soil Science
Luis Alfredo Pires Barbosa, Lars J. Munkholm, Peter Bilson Obour, Thomas Keller
Article
Soil Science
Renato P. de Lima, Thomas Keller
Summary: The study found that soil stress is typically overestimated by transducer probes. The overestimation decreases with probe diameter to height ratio, and increases with the ratio of probe to soil elastic modulus. Probes interfere with each other when the vertical gap between adjacent probes is closer than about three times probe diameter. Measured stress is influenced by soil depth and size of the loaded area.
SOIL & TILLAGE RESEARCH
(2021)
Article
Soil Science
Thomas Keller, Tino Colombi, Siul Ruiz, Stanislaus J. Schymanski, Peter Weisskopf, John Koestel, Marlies Sommer, Viktor Stadelmann, Daniel Breitenstein, Norbert Kirchgessner, Achim Walter, Dani Or
Summary: This study aimed to quantify short-term soil structure recovery under natural conditions with and without plant cover, revealing that two years after compaction event, soil physical properties have not fully recovered even within the topsoil. Recovery rates differ among soil properties, with permeability showing the highest recovery rates. The concept of soil structure recovery proceeding from the surface downward and expanding around biologically-active pockets could be tested with additional data.
SOIL SCIENCE SOCIETY OF AMERICA JOURNAL
(2021)
Article
Ecology
Yvan Capowiez, Stephane Sammartino, Thomas Keller, Nicolas Bottinelli
Summary: Increasing soil bulk density negatively impacts the burrowing behavior and soil water infiltration of endogeic earthworms, leading to a decrease in burrow system characteristics. Despite the decrease in water infiltration as soil bulk density increases, burrows made by endogeic earthworms can moderately increase water infiltration when soil bulk density is low. These findings could help refine simulation models of earthworm burrowing behavior in relation to soil water content, temperature, and bulk density.
Article
Plant Sciences
Hanna Sjulgard, Daniel Iseskog, Norbert Kirchgessner, A. Glyn Bengough, Thomas Keller, Tino Colombi
Summary: The study revealed that pea roots exhibit reversible responses to short-term soil physical stress, while wheat roots show irreversible responses, indicating different root phenotypic plasticity between the two species. This suggests that strategies to cope with periodic soil physical stress may vary among species.
ENVIRONMENTAL AND EXPERIMENTAL BOTANY
(2021)
Article
Environmental Sciences
Alejandro Romero-Ruiz, Niklas Linde, Ludovic Baron, Santiago Gabriel Solazzi, Thomas Keller, Dani Or
Summary: Subtle changes in soil structure have significant impacts on soil mechanical and hydraulic properties, with implications for agricultural management. This study successfully predicted soil changes due to compaction using a proposed model.
VADOSE ZONE JOURNAL
(2021)
Article
Environmental Sciences
Alejandro Romero-Ruiz, Niklas Linde, Ludovic Baron, Daniel Breitenstein, Thomas Keller, Dani Or
Summary: Characterizing and quantifying soil structure in the field remains a challenge despite its importance for hydrological and ecological soil functioning. This study expands the application of geoelectrical and time-domain reflectometry monitoring to infer the impacts of compaction on soil structure and function. The findings suggest that soil compaction leads to a decrease in soil electrical resistivity and drier soil conditions.
WATER RESOURCES RESEARCH
(2022)
Article
Multidisciplinary Sciences
Thomas Keller, Dani Or
Summary: Mechanization has led to the success of modern agriculture, but the increased weight of farm machinery has raised concerns about subsoil compaction. Research shows that 20% of arable land is at risk of chronic subsoil compaction, leading to potential loss of productivity. The study also suggests that prehistoric giants may have had similar effects on land productivity due to subsoil compaction.
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
(2022)
Article
Biodiversity Conservation
Philippe Tschanz, Stefan Vogel, Achim Walter, Thomas Keller, Matthias Albrecht
Summary: Ground-nesting wild bees play a crucial role in pollinating wild plants and crops, impacting human wellbeing. This study in Switzerland found that arable fields are utilized for nesting by various bee species, with nest density being positively related to the proportion of bare ground and decreasing with distance from field edges. The findings suggest that maintaining small field sizes, increasing edge density, and reducing crop cover through increased row spacing can support ground-nesting bees in agricultural landscapes, potentially aided by floral-rich agri-environment scheme areas. Further research is needed to determine if tilled arable fields serve as suitable nesting habitats or ecological traps for ground-nesting bees.
JOURNAL OF APPLIED ECOLOGY
(2023)
Article
Agronomy
Laerke Daverkosen, Alena Holzknecht, Jurgen K. Friedel, Thomas Keller, Bjarne W. Strobel, Annelie Wendeberg, Sabine Jordan
Summary: This study aims to investigate the impact of regenerative management practices on soil health indicators in Gotland, Sweden. The results show that the application of organic matter has a positive effect on soil indicators, while reduced tillage and increased share of perennials have a positive impact on vegetation density and root abundance. Additionally, cluster analysis reveals significant differences in soil indicators among different management types.
JOURNAL OF PLANT NUTRITION AND SOIL SCIENCE
(2022)
Article
Soil Science
Philippe Tschanz, John Koestel, Valerio Volpe, Matthias Albrecht, Thomas Keller
Summary: Most research on wild bees has focused on their role as pollinators, but their importance as soil ecosystem engineers has been largely overlooked. This study used X-ray computed tomography to examine the morphology and temporal evolution of ground-nesting bee burrows, and found significant differences between species. The study highlights the potential of X-ray imaging to gain insights into the underground life of ground-nesting bees and emphasizes their importance as soil ecosystem engineers.
Article
Biodiversity Conservation
Florian Walder, Lucie Buechi, Cameron Wagg, Tino Colombi, Samiran Banerjee, Juliane Hirte, Jochen Mayer, Johan Six, Thomas Keller, Raphael Charles, Marcel G. A. van Der Heijden
Summary: One of the critical challenges in agriculture is to enhance yield without compromising soil health and the environment. This study compared the effects of conventional, no-till, and organic management on production and soil health. The results suggest that organic management improves soil health but leads to lower yields, while no-till systems show intermediate results. The study highlights the importance of balanced approaches that combine crop diversification, organic amendments, and effective crop protection to achieve multifunctional agroecosystems.
JOURNAL OF APPLIED ECOLOGY
(2023)
