Vadose Zone Journal最新文献

{"title":"Coupled hydro‐mechanical pore‐scale modeling of biopore‐coated clods for upscaling soil shrinkage and hydraulic properties","authors":"Luis Alfredo Pires Barbosa, Horst H. Gerke","doi":"10.1002/vzj2.20325","DOIUrl":"https://doi.org/10.1002/vzj2.20325","url":null,"abstract":"Earthworms and plant roots are vital for macropore formation and stabilization. The organo‐mineral coating of biopore surfaces also regulates macropore‐matrix mass exchange during preferential flow. The influence of finer‐textured burrow coatings on macroscopic soil properties during shrinkage could potentially be assessed by upscaling pore‐scale hydraulic and mechanical simulations. The aim was to investigate the influence of micro parameters (particle size, stiffness, and bond strength) on macro parameters (i.e., shrinkage curve and soil hydraulic properties). Drainage experiments and simulations were carried out using biopore‐coated clod‐size samples compared to those without coating. Simulations were performed using a two‐phase pore‐scale finite volume coupled with discrete element model (DEM‐2PFV). The structural dynamics was characterized by analyzing the pore volume and soil shrinkage curve obtained from numerically determined data. The soil hydraulic parameters were described using uni‐ and bimodal van Genuchten (vG) functions. The drainage simulations revealed hydro‐mechanical dynamics characterized by Braudeau‐shrinkage curve subdomains: The matrix‐only samples, with lower particle bond strength, exhibited relatively higher shrinkage. The coated samples, with higher particle stiffness and bond strength, displayed greater hydro‐mechanical stability. The numerically determined initial value of the saturated hydraulic conductivity (<jats:italic>K<jats:sub>s</jats:sub></jats:italic>) was about 70 times larger for matrix‐only samples than for coated samples. As expected, for the nonrigid soil structures, constant <jats:italic>K<jats:sub>s</jats:sub></jats:italic>, <jats:italic>α</jats:italic>, and <jats:italic>n</jats:italic> values for bimodal vG model resulted in prediction errors. Upscaling DEM‐2PFV pore‐scale model outcomes quantifies micro‐coating effects on macro hydro‐mechanics. This yields void ratio‐based soil water retention and hydraulic conductivity functions, advancing macroscopic soil hydraulic models and enhancing structured soil flow and transport descriptions.","PeriodicalId":23594,"journal":{"name":"Vadose Zone Journal","volume":null,"pages":null},"PeriodicalIF":2.8,"publicationDate":"2024-04-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140578354","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Implementation of the Brunswick model system into the Hydrus software suite","authors":"Efstathios Diamantopoulos, Jirka Simunek, Tobias K. D. Weber","doi":"10.1002/vzj2.20326","DOIUrl":"https://doi.org/10.1002/vzj2.20326","url":null,"abstract":"The Brunswick modular framework for modeling unsaturated soil hydraulic properties (SHP) over the full moisture range was implemented in the Hydrus suite. Users can now additionally choose between four different variants of the Brunswick model: (i) van Genuchten–Mualem (VGM), (ii) Brooks–Corey, (iii) Kosugi, and (iv) modified van Genuchten. For demonstration purposes, simulation results for two different setups, (i) bare soil evaporation and (ii) root water uptake, are presented, along with a comparison of the original VGM model and its Brunswick variant. Results show that the original VGM model underestimates the simulated cumulative evaporation and cumulative transpiration due to the inconsistent representation of the SHP in the dry moisture range. We also implemented a two‐step hydro‐PTF (pedotransfer function) into the Hydrus suite that converts the parameters of the original VGM model (from Rosetta) to the corresponding Brunswick variant. In that way, physically comprehensive simulations are ensured if no data on SHP are directly available, but information on physical soil properties (e.g., texture and bulk density) exists.","PeriodicalId":23594,"journal":{"name":"Vadose Zone Journal","volume":null,"pages":null},"PeriodicalIF":2.8,"publicationDate":"2024-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140578256","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Averaging or adding domain conductivities to calculate the unsaturated soil hydraulic conductivity","authors":"Gerrit H. de Rooij","doi":"10.1002/vzj2.20329","DOIUrl":"https://doi.org/10.1002/vzj2.20329","url":null,"abstract":"Recent models of the unsaturated hydraulic conductivity curve (UHCC) are the sum of separate UHCCs for domains of capillary water, film water, and water vapor. This requires parallel, noninteracting domains. A theoretical framework for aggregating domain conductivities to a bulk soil UHCC is presented to identify and possibly relax implicit assumptions about domain configuration. The paper develops arithmetic, harmonic, and geometric averages of the liquid-water conductivities that can be arithmetically averaged with the vapor conductivity. However, current models for capillary and film conductivities are intrinsic, that is, valid within their respective domain. The vapor conductivity is a bulk conductivity, that is, it gives the conductivity of the gaseous domain as it manifests itself in the soil. Conversion relationships use the domain volume fractions as approximations of the as-yet unknown weighting factors to convert between intrinsic and bulk conductivities. This facilitates consistent averaging of domain conductivities. Even with consistent averaging, a truly physically accurate model of the UHCC based on domain conductivities is fundamentally elusive. Nevertheless, models based on the three averages and the unweighted sum of the domain conductivities produce good fits to data for two soils but diverge in the dry range. The fitted curves for the capillary and film water depend on the averaging (or adding) method. Hence, they are not strictly characteristic of their respective domains. The true intrinsic domain conductivity functions may be impossible to determine.","PeriodicalId":23594,"journal":{"name":"Vadose Zone Journal","volume":null,"pages":null},"PeriodicalIF":2.8,"publicationDate":"2024-03-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140324490","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Rien van Genuchten: A short autobiography","authors":"Martinus Th. van Genuchten","doi":"10.1002/vzj2.20322","DOIUrl":"https://doi.org/10.1002/vzj2.20322","url":null,"abstract":"<h2>1 INTRODUCTION</h2>\u0000<p>I am extremely honored to receive the 2023 Wolf Prize in the field of agriculture for “groundbreaking work in understanding water flow and predicting contaminant transport in soils,” and for that reason, being invited to contribute an autobiography to this special section of <i>Vadose Zone Journal</i>. Receiving the Wolf Prize reflects the guidance, support, and input I received from so many over the years, starting from the very beginning from my parents who instilled in me the beauty of the natural environment through their careful management of a small family farm in the Netherlands. They encouraged me to pursue my MS studies in Holland, after which I went to the United States, subsequently to Brazil, and back to the Netherlands. Throughout my life, I enjoyed enormous freedom to pursue whatever I felt was important to better describe fluid flow and contaminant transport processes in the near-surface environment. I could interact with a large number of colleagues from all over the world. This collaboration made me see not only the important gaps in science but also the difficulties of applying what we know to the many environmental and socio-economic problems facing this planet. As such, my appreciation goes to the Wolf Foundation for recognizing, through this award, the importance of us taking care of this planet and its inhabitants.</p>","PeriodicalId":23594,"journal":{"name":"Vadose Zone Journal","volume":null,"pages":null},"PeriodicalIF":2.8,"publicationDate":"2024-03-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140298857","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Downscaling SMAP soil moisture product in cold and arid region: Incorporating NDSI and BSI into the random forest algorithm","authors":"Mingxing Gao, Kui Zhu, Yanjun Guo, Xuhang Han, Dongsheng Li, Shujian Zhang","doi":"10.1002/vzj2.20323","DOIUrl":"https://doi.org/10.1002/vzj2.20323","url":null,"abstract":"Soil moisture (SM) is a critical element of the hydrological cycle, land surface processes, and surface energy balance. However, the low spatial resolution of commonly used SM products limits the application of SM in agriculture and eco‐hydrology in cold and arid regions. In this study, the normalized difference soil index (NDSI) and bare soil index (BSI) were added to traditional downscaling factors including land surface temperature, normalized difference vegetation index, digital elevation mode, apparent thermal inertia, Albedo, and temperature vegetation dryness index, as they are more strongly correlated with surface SM in the bare soil‐vegetation alternation zone of such region. Using the random forest algorithm, a downscaling model of SM was constructed for such region. The accuracy of the downscaled SM estimates was validated by comparing them with the original SM data collected from May to September 2021, which is the non‐freezing period of the soil. The findings indicate that the newly added NDSI and BSI have good correlation with SM. Incorporating NDSI and BSI to construct the downscaled model enhances the accuracy by over 19% compared to excluding them, while also providing a more comprehensive representation of SM information. NDSI and BSI can be well applied to the downscaled research of SM in the bare soil‐vegetation alternation zone, which is of great value for the study of eco‐hydrology and agricultural drought monitoring in cold and arid regions.","PeriodicalId":23594,"journal":{"name":"Vadose Zone Journal","volume":null,"pages":null},"PeriodicalIF":2.8,"publicationDate":"2024-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140200877","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Neutron imaging of exchange flow between biopore and matrix for Bt versus C horizons","authors":"Luis Alfredo Pires Barbosa, Fernando Vieira Lima, Horst H. Gerke","doi":"10.1002/vzj2.20320","DOIUrl":"https://doi.org/10.1002/vzj2.20320","url":null,"abstract":"The surface coating of biopores plays a pivotal role in mediating mass exchange between the biopore and the soil matrix, ultimately governing preferential flow in structured soils. However, quantitative experiments of the flow exchange dynamics in the soil around an earthworm burrow (drilosphere) are limited. Here, we developed an experimental setup to mimic preferential flow within a biopore while monitoring the water distribution by neutron radiography. The objective was to quantify the evolving water content distribution in the biopore with surrounding drilosphere samples from Bt and C horizons. We hypothesize that the distribution of clay and organic material across biopore surfaces in Bt and C horizons impacts the biopore coating material formation (i.e., composition and thickness), thereby influencing its role in controlling mass exchange during preferential flow events. The experimental setup was proposed for in situ quantification of the preferential flow dynamics in an earthworm burrow (biopore) passing through Bt and C horizons of a Luvisol developed on glacial till. The neutron radiographies were obtained at the NEUtron Transmission Radiography facility of the Paul Scherrer Institut, Villingen. The volumetric water content was quantified by calibrating gray scale values from radiography images with defined water contents using stepped aluminum cuvettes attached to the samples; image analysis was used to determine sorptivity at the biopore–soil matrix interface. The water exchange flow was found to be smaller for coated biopore surface in the more clayey Bt horizon, as compared to the coarser textured carbonaceous subsoil C horizon, where higher sorptivity intensified mass exchange. The method most realistically captured the dynamics of the vertical preferential flow process in a biopore, including lateral exchange flow, by determining the water sorptivity of the drilosphere. In contrast to mini‐infiltrometer data, biopore–matrix exchange flow was here more restricted for Bt in contrast to carbonaceous C horizon. Since both horizons showed the presence of coating material on their burrow walls, the results suggest further analysis of their contrasting properties and structures.","PeriodicalId":23594,"journal":{"name":"Vadose Zone Journal","volume":null,"pages":null},"PeriodicalIF":2.8,"publicationDate":"2024-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140200930","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Soil salinization in Portugal: An in‐depth exploration of impact, advancements, and future considerations","authors":"Tiago B. Ramos, Maria C. Gonçalves, Martinus Th. van Genuchten","doi":"10.1002/vzj2.20314","DOIUrl":"https://doi.org/10.1002/vzj2.20314","url":null,"abstract":"Soil salinization poses a significant threat to agricultural production in Portugal. Collaborative research spanning three decades with the U.S. Salinity Laboratory in Riverside, California, has been instrumental in advancing our understanding of this issue. This study provides a concise overview of the causes of soil salinization in Portugal, focusing on ongoing efforts to comprehensively address this challenge. Key advancements highlighted in this study encompass the meticulous characterization of soil hydraulic and solute transport parameters, the application of cutting‐edge modeling tools for water flow and solute transport in diverse agricultural systems, and the utilization of innovative proximal and remote sensing methods for mapping soil salinity. Noteworthy results and practical implications of these advancements underscore their relevance in real‐world scenarios. While celebrating these achievements, the study emphasizes the current nature of the ongoing research, highlighting the dynamic landscape of soil salinization. The study underscores the imperative need for further advancements to effectively cope with soil salinization, especially in anticipation of the intensification of agricultural practices and the looming impacts of climate change. This comprehensive overview not only encapsulates past achievements but also sets the stage for future research endeavors in mitigating the pervasive effects of soil salinization on agricultural sustainability in Portugal.","PeriodicalId":23594,"journal":{"name":"Vadose Zone Journal","volume":null,"pages":null},"PeriodicalIF":2.8,"publicationDate":"2024-03-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140165376","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Elucidating the role of water films on solute diffusion in unsaturated porous media by improved pore-scale modeling","authors":"Yuankai Yang, Ravi A. Patel, Nikolaos I. Prasianakis, Sergey V. Churakov, Guido Deissmann, Dirk Bosbach","doi":"10.1002/vzj2.20321","DOIUrl":"https://doi.org/10.1002/vzj2.20321","url":null,"abstract":"Solute diffusion in partially saturated porous media is an important fundamental process in many natural and environmental systems. At low water saturation, the solute transport is governed by the diffusion in thin water films on the surfaces of solids. In this study, we established an improved pore-scale simulation framework successfully describing the solute diffusion in variably saturated porous media (e.g., soils), which considers the contribution of the diffusion within the thin water film on the surface of the solid matrix. The model takes into account the liquid–gas distribution in the underlying porous media by the Shan-Chen lattice Boltzmann Method (LBM) and simulates the solute diffusion in the bulk liquid phase and the water film. Based on the numerical results, an easy-to-use theoretical formula was also developed to predict the effective diffusivity in microporous materials at low saturation levels. The average relative error of its prediction with respect to the experimental data from the literature is about 30%, while that of the classical power law exceeds 70%. A simple phase diagram was defined, which allows us to identify the situations under which it is necessary to take the influence of surface water films on the effective diffusivity in unsaturated microporous media into account. The present study improves the pore-scale model to address solute diffusion in the water films at low water saturation and elucidates the contribution of thin water films on solute transport.","PeriodicalId":23594,"journal":{"name":"Vadose Zone Journal","volume":null,"pages":null},"PeriodicalIF":2.8,"publicationDate":"2024-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140155342","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Modeling N fertilization impact on water cycle and water use efficiency of maize, finger‐millet, and lablab crops in South India","authors":"Albara Almawazreh, Daniel Uteau, C. T. Subbarayappa, Andreas Buerkert, Sybille Lehmann, Stephan Peth","doi":"10.1002/vzj2.20319","DOIUrl":"https://doi.org/10.1002/vzj2.20319","url":null,"abstract":"The understanding of the impact of nitrogen (N) fertilization on the field water cycle and corresponding water use efficiency (WUE) is very important for optimizing fertilization rates and conserving stressed water resources. We modeled soil moisture dynamics of maize (<jats:italic>Zea mays</jats:italic> L.), finger millet (<jats:italic>Eleusine coracana Gaertn</jats:italic>.), and lablab [<jats:italic>Lablab purpureus</jats:italic> (L..) <jats:italic>Sweet</jats:italic>] plots using calibrated HYDRUS‐1D model on two experimental sites (rain‐fed and irrigated) for three seasons under different N treatments. The results indicate that the effects of N depended on plant specific properties such as N‐fixation and drought tolerance, and on plant available water content governed by soil structure and rainfall seasonal variability. Maize WUE of plots which received 150 kg/ha of urea (46 N) were 10–30 kg/ha/mm higher than plots which received none; likewise, millet that received 50 kg/ha of urea had a 7–10 kg/ha/mm higher WUE than control plots in both experiments. However, differences in water cycle components were noticeable between N treatments only in the rain‐fed experiment, where higher N levels led to around 60 and 30 mm higher transpiration, 30 and 20 mm lower evaporation, and 30 and 15 mm lower percolation per season for maize and millet, respectively. In 2018, which was the driest year, the difference in maize WUE between the high and low N treatments was only 1 kg/ha/mm, which corresponded with low actual to potential transpiration ratios (). This indicates higher sensitivity of maize to water stress compared to the other crops. The results of lablab indicate a positive impact of N fertilization on WUE only under water‐limited conditions.","PeriodicalId":23594,"journal":{"name":"Vadose Zone Journal","volume":null,"pages":null},"PeriodicalIF":2.8,"publicationDate":"2024-03-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140154899","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Hydro‐pedo‐transfer‐functions expressing drought and memory effects on pine tree growth","authors":"Gerd Wessolek, Winfried Riek, Klaus Bohne","doi":"10.1002/vzj2.20317","DOIUrl":"https://doi.org/10.1002/vzj2.20317","url":null,"abstract":"Over the last 30 years, the impact of climate change in Berlin, Germany, has manifested in the form of reduced summer rainfall, elevated temperatures, and a notable rise in the frequency of days with temperatures surpassing 30°C. All of them are leading to a decreasing water supply and increasing risk of drought. Various field, laboratory, and numerical simulation studies have been done for deriving information on long‐term potential and actual evapotranspiration, water stress during the vegetation period (April–September), and tree ring growth of various pine tree stands in Berlin. Data analysis highlights periodical climate patterns and complex interactions between drought, water supply, and plant growth. Annual tree ring growth is not only related to the actual weather conditions but also to the past climate years. With decreasing water supply, this kind of drought memory effect increases up to 5 years into the past. For Berlin's climate, it is noteworthy that late summer, particularly the water stress in August, represents the most sensitive indicator for tree ring growth.For regionalization purposes, long‐term numerical simulations were done to derive hydro‐pedo‐transfer‐functions (HPTFs) predicting the water stress coefficient of the growing season (<jats:italic>E</jats:italic><jats:sub>act‐s</jats:sub>/<jats:italic>E</jats:italic><jats:sub>pot‐s</jats:sub>). They only need easily available information such as soil texture, climate water balance, and groundwater depth. Two HPTFs were successfully tested and can be easily applied by geo‐information systems. However, for other climate regions and tree species, HPTFs need to be adapted.","PeriodicalId":23594,"journal":{"name":"Vadose Zone Journal","volume":null,"pages":null},"PeriodicalIF":2.8,"publicationDate":"2024-03-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140019678","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}