In recent groundbreaking research, scientists have uncovered pivotal insights into how cracks influence the soil-water characteristic curves (SWCC) of lateritic soils, an advancement that could revolutionize our understanding of soil behavior in tropical and subtropical regions. Lateritic soils, known for their unique composition and widespread distribution in global warm climates, play an essential role in agriculture, construction, and environmental sustainability. The latest study spearheaded by Wendong, W., Xiaowen, L., and Ali, M., and published in Environmental Earth Sciences, delves into the subtle but critical interactions between soil fractures and water retention dynamics, challenging previously held conventions in soil mechanics and hydraulic modeling.
Lateritic soils are notoriously complex due to their iron and aluminum-rich mineralogy, which significantly affects their porosity, permeability, and water retention properties. Traditionally, soil-water characteristic curves, which describe the relationship between soil suction and water content, have been modeled under the assumption of intact soil matrices. However, natural conditions frequently produce cracks, fractures, and other discontinuities that fundamentally alter how water moves through and is retained by soil. The study in question methodically investigates this phenomenon by focusing on how these cracks modify the SWCC, a factor often overlooked in conventional geotechnical and hydrological analyses.
The researchers began by meticulously preparing samples of lateritic soils and artificially inducing cracks of varying sizes and distributions to simulate field conditions. Advanced experimental setups measured changes in matric suction and volumetric water content, recording shifts in water retention parameters as cracks developed and evolved. By doing so, they established a direct correlation between crack presence and a pronounced alteration in hydraulic behavior. The data demonstrated that cracks significantly disrupt capillary forces and soil-water interaction mechanisms, leading to a discernible deviation in the typical soil-water characteristic curve patterns that previously guided irrigation and drainage engineering designs.
One of the most striking revelations from this investigation is how the cracks influence the hysteresis effect in soil-water retention. Usually, soils display different water retention stories depending on whether they are wetting or drying. The presence of cracks tends to amplify this hysteresis, resulting in more complex retention profiles that need to be accounted for in simulation models. Such complexity undermines assumptions of soil homogeneity and isotropy and forces a rethinking of how we model water flow in fractured systems, especially under climatic stress such as drought or heavy rainfall.
Furthermore, the research highlights how the scale and connectivity of cracks impose a substantial impact on preferential flow pathways. Rather than migrating diffusely through the soil matrix, water can rapidly move through these fractures, bypassing the finer pore space, which alters the effective hydraulic conductivity and retention characteristics. This can lead to uneven moisture distribution beneath the soil surface, exacerbate erosion risks, and impact root water uptake, which in turn affects plant health and agricultural yields. Understanding these dynamics opens new frontiers in precision agriculture and sustainable land management.
An additional layer of complexity stems from the temporal evolution of cracks influenced by wetting-drying cycles, mechanical stresses, and chemical weathering. The study underscores that cracks are not static; they grow, shrink, and propagate following environmental triggers, resulting in dynamically shifting soil-water interaction landscapes. Modeling such transient behavior challenges existing soil-water retention paradigms and calls for integrating temporal dimensions into hydrological models, something that few current practices adequately address.
The role of lateritic soils as a critical component of tropical ecosystems makes this research crucial. Due to their extensive distribution across regions such as Africa, South America, and Southeast Asia, enhancing the understanding of their hydrological properties helps improve water resource management, natural hazard prediction, and infrastructure development in these areas. The findings reveal that crack-induced modifications to water retention greatly influence soil stability, affecting landslide susceptibility and foundation bearing capacity, which are major concerns in many rapidly developing tropical regions.
This investigation utilized sophisticated imaging techniques and numerical simulations to visualize and quantify cracks in three dimensions, offering unprecedented detail on the spatial heterogeneity of soil fractures and their influence on water retention properties. The integration of experimental and numerical approaches enabled the researchers to derive more accurate SWCC models that incorporate crack effects, moving beyond oversimplified representations that have dominated the field for decades.
The study also discusses potential implications for climate change resilience strategies. As precipitation patterns become more erratic and extreme weather events more common, the behavior of soils under these changing conditions becomes increasingly important. The presence of cracks as identified in lateritic soils can either mitigate or exacerbate the impacts of water infiltration and retention during intense storms or prolonged droughts. A deeper grasp of these processes may guide future agricultural practices and infrastructure planning, ensuring that societies relying on these soils for food production and urban development can adapt more effectively.
Beyond practical applications, the research offers a theoretical framework that links soil fracture mechanics with hydraulic properties. This interdisciplinary approach bridges gaps between geotechnical engineering, soil physics, and hydrology disciplines, producing a holistic perspective on fractured soil behavior. It suggests novel avenues for future research, such as exploring how biotic factors like root growth and microbial activity influence the formation and persistence of cracks and their combined effect on soil-water dynamics.
The authors emphasize caution in applying conventional SWCC models in environments where lateritic soils exhibit prevalent cracking. They advocate for revising standard procedures by integrating site-specific investigations of crack networks, which can differ drastically based on environmental history and land use. This calls for enhanced field monitoring methods and more frequent soil sampling to capture the evolving nature of soil-water relationships under real-world conditions.
Moreover, the study sheds light on the challenge of measuring soil suction in cracked soils, proposing improved measurement techniques that account for air entry into cracks and the resulting changes in suction readings. Accurate measurement of these parameters is essential for developing reliable predictive models of soil behavior under various moisture regimes, particularly for engineering applications requiring precise knowledge of soil-water interactions.
Among the broader environmental consequences, changes in the soil-water characteristic curve due to cracks can affect groundwater recharge rates and pollutant transport. Water moving rapidly through cracks can exacerbate contamination risks by preferentially channeling pollutants to deeper soil layers and aquifers, making this research relevant to environmental protection and public health strategies.
The implications of this study extend into the realm of ecosystem services, as soil moisture dynamics influence vegetation patterns, carbon sequestration, and nutrient cycling. With better modeling of crack effects on soil-water relations, ecologists and land managers can enhance their understanding of soil function and resilience, informing conservation strategies that bolster ecosystem sustainability under changing climatic conditions.
Future research directions outlined by the authors include expanding the scope to other soil types with different mineral compositions and crack characteristics, as well as incorporating the effects of vegetation roots and anthropogenic activities. This comprehensive approach promises to uncover new insights into the complex interactions that govern soil-water physics and their practical implications worldwide.
In conclusion, this pioneering research into the effect of cracks on soil-water characteristic curves in lateritic soils not only advances the fundamental science of soil mechanics and hydrology but also holds profound implications for agriculture, environmental management, and engineering in tropical regions. By illuminating the intricacies of cracked soil-water interactions, the study paves the way for more accurate modeling, better risk assessment, and innovative strategies to cope with the challenges posed by ever-changing environmental conditions.
Subject of Research: The effect of cracks on soil-water characteristic curves in lateritic soils.
Article Title: Effect of cracks on soil-water characteristic curves of lateritic soils.
Article References:
Wendong, W., Xiaowen, L. & Ali, M. Effect of cracks on soil-water characteristic curves of lateritic soils. Environ Earth Sci 84, 561 (2025). https://doi.org/10.1007/s12665-025-12531-7
Image Credits: AI Generated
