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Evaporation of water from soils is a three-stage process that has great significance in stress development in exposed geotechnical structures, generation of dusts that can cause environmental pollution and respiratory ailments, and dereliction of land by generating drought conditions. In this study, the factors that influence water evaporation from...
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... proved 1 that the air entry value and hydraulic conductivity of soil are critical factors that affect the 2 sizes. Specifically, the particle size of the sand used ranges from 0.2 to 0.5 mm in Set Q1, from 0.5 1 to 1 mm in Set Q2; and from 2 to 3 mm in Set Q3 (Table 2). The soil samples were prepared at the 2 same thickness of 28 mm and with the same sand mix proportion of 50%. ...Citations
... Cl-concentricity in precipitation in midcontinent regions is often less than 1 mg/L, and always less than 0.1 mg/L [4]. Upon contacting earth roof, Cl concentricity in water raise as a result of interacts with soils, rocks, and biota (waste products), as well as the impacts of evaporation [5]. Chlorides are the most superabundant ions in freshwater, with a concentricity super than 860ppm [6]. ...
... This can be explained by the following factors. On the one hand, according to An et al. (2018), higher sand content results in larger evaporation area and thereby allowing higher evaporation rate. Therefore, comparing to sandy soil and silt which contain some clay particles, the evaporation rate of meltwater in silica sand is faster. ...
Electrical resistivity method has been widely used to study permafrost and to monitor the process of freezing-thawing. However, a thorough understanding of the mechanism of electrical response during thawing is missing. In this study, we investigated the thawing behavior of saline soils in the temperature range ∼-10 to 15 °C considering the effects of soil type and salinity. A total of nine experiments were performed with three soil types (silica sand, sandy soil and silt) and three salinities (0.01 S/m, 0.1 S/m and 1 S/m). The results show that resistivity variations with temperature can be divided into three stages. In Stage I, tortuosity and unfrozen water content play major roles in the decrease of resistivity. In Stage Ⅱ, which is an isothermal or near isothermal process, resistivity still decreases slightly due to the thawing of residual ice and pore water movement. In Stage III, ionic mobility plays an important impact on decreasing resistivity. In addition, the isothermal process is found to only occur in silica sand which can be explained by latent heat effect. Exponential and linear models linking temperature with resistivity are used to fit the experimental data in Stage I and Stage III. The fitting parameter in different models shows great correlation with soil type and salinity. Furthermore, unfrozen water content below 0 °C is also estimated and uncertainty of estimation is analyzed.
... Here, evaporation rate is defined as the gradient of the relationship between the mass of water evaporated from the specimen and elapsed time. The evaporation rate was almost constant during the tests for all the specimens ( Table 7), suggesting that water phase remained continuous, and the water transported from the depths to the soil surface may be driven by capillary pressure differences between pores [3,31]. It has been reported that the capillary difference required to maintain a constant evaporation rate is not determined by one single pore size, but the difference in the size of the small and large pores [38,64]. ...
Hydrochar is an urban soil amender that supports plant growth on slopes. It is a biomass-derived carbon-rich material produced by the hydrothermal carbonation process; thus, it has a different pore structure from biochar produced by pyrolysis. The effects of hydrochar on the hydraulic properties of unsaturated compacted soils and the underlying pore-level soil-hydrochar interaction mechanisms are unclear. In this study, silty-clay sand was amended by grass-derived hydrochars produced at two hydrothermal carbonisation temperatures (180 and 240 °C, denoted as H-180 and H-240, respectively) with different mass proportions (\({f}_{{\text{H}}}\)). The pore and throat size distributions, water retention curves (WRCs) and hydraulic conductivity functions (HCFs) of the soils with and without amendment were measured. The results showed that hydrochar improved the soil water retention capability as the smaller hydrochar particles filled the soil pores with diameters larger than 290 μm. Compared with the increase in air-entry value made by H-180, the one made by H-240 was more substantial as this type of hydrochar altered the soil pores to be smaller in size. Hydrochar also increased the hydraulic conductivity of the soil by half to one order of magnitude due to the increase in the throat frequency and the presence of hydrochar intra-pores. One exception was the amendment by H-180 at \({f}_{{\text{H}}}\) of 2.5%, wherein the HCF was reduced due to pore clogging at throat diameters less than 90 μm and more than 250 μm. Finally, amending the soil with either H-180 or H-240 at \({f}_{{\text{H}}}\) of 5% always improved the WRC and HCF, thereby benefiting plant water uptake.
... It has been demonstrated that SM is a critical surface state variable on which ET depends (Purdy et al., 2018;Zhou et al., 2021;Yao et al., 2023), and therefore had an important impact on ET/ETpot (Mintz and Walker, 1993;Komatsu, 2003;Detto et al., 2006, Fisher et al., 2008Teng et al., 2014;An et al., 2018;Brust et al., 2021). For example, Detto et al. (2006) analysed the F-SM relationship in a heterogeneous rain-fed Mediterranean ecosystem with three different land covers. ...
... For example, Detto et al. (2006) analysed the F-SM relationship in a heterogeneous rain-fed Mediterranean ecosystem with three different land covers. Komatsu (2003), Teng et al. (2014), and later An et al. (2018), studied the effect of SM on F from bare soils data, acquired under controlled conditions. Fisher et al. (2008) proposed to constraint ET by a function of SM (fSM), which is an index of SM deficit based on the complementary hypothesis of Bouchet (1963). ...
... Previous F formulations (Mintz and Walker, 1993;Komatsu, 2003;Detto et al., 2006;An et al., 2018;Liu, 2022), did not take into account the importance of atmospheric variables in the formulation. Considering Fisher et al. (2008), F can be explained by VPD, RH, and SM. ...
Accurate monthly evapotranspiration (ET) estimation is essential for many forest, climate, and hydrological applications, as well as for some agricultural uses. In this study, the relationship between ET and relative evapotranspiration (F) using land surface, and atmospheric variables was assessed with 17 FLUXNET sites data in savanna, cropland, and forest land covers, distributed all over the world. A sigmoid (Fs) and a logarithmic (Fl) F expression were included in Walker et al.’s (2019a,b) equations to evaluate their impact on the accuracy of ET estimations. The new parameterizations of ET outperformed the original expression, showing root mean square errors lower than 24% of the mean observed ET. The results presented here suggest that atmospheric parameters, coupled with land explanatory variables included in F estimates, produce more precise ET estimations. In addition, Soil Moisture Active Passive (SMAP) products were used to obtain global maps of ET and compared with Global Landsurface Evaporation Amsterdam Methodology (GLEAM) and Terra Moderate Resolution Imaging Spectroradiometer (MODIS) MOD16 products, displaying the flexibility of these new parametrizations with different sources of data.
... The variations of water evaporation rate in soil samples before and after different cycles of MICP treatment are shown in Fig. 3. According to the previous research [5], the natural soil evaporation rate is generally characterized by two distinct periods: stage I, an initially high and relatively constant evaporation rate; and stage II, a lower and gradually falling evaporation rate. Before MICP treatment (Fig. 3a), two evaporation stages were observed clearly in all samples with different layer thicknesses, the soil sample with the larger layer thickness presented the higher evaporation rate and the longer duration of the constant rate stage I. ...
Intensified drought exacerbated by climate change aggravates the development of soil desiccation cracking, triggering several weakening mechanisms in surface soils and eventually causing various geohazards and environmental problems. This study investigates the effect and mechanisms of a bio-mediated approach based on microbially induced calcite precipitation (MICP) for remediation of desiccation cracks in soils with different layer thicknesses. We conducted 5 MICP treatment cycles on clayey soil samples to explore the influence of layer thickness on the water evaporation properties, desiccation cracking behaviors, and calcium carbonate content and distribution of MICP-treated soils. The results show that the MICP treatment can significantly decrease the water evaporation rate, the surface crack ratio, average crack width, and total crack length of all soil samples. The crack reduction ratio reaches over 90% after 5 MICP treatment cycles. The soil layer thickness has an obvious influence on the effectiveness of MICP for the clayey soil treatment. Thicker soil samples exhibit wider desiccation cracks, which, in turn, require more MICP treatment cycles for remediation. The calcium carbonate content and distribution of MICP-treated soils is governed by the original desiccation cracks, the wider cracks in thicker soil samples result in the higher calcium carbonate content of soil nearby the cracks, and the denser cracks in thinner soil samples lead to the more homogenous distribution of calcium carbonate. The remediation of soil desiccation cracks is mainly attributed to the coupling effect of the soil volume change and the accumulation of calcium carbonate crystal during MICP treatment. The findings of this study provide new insights into the mechanisms of the interaction between MICP-treated soil and drought climate and contribute to developing environmentally friendly approaches for soil improvement in regions subjected to droughts.
... However, most scholars use indoor experiments combined with image processing software to study the morphological characteristics of soil evaporative cracking [15][16][17][18]. Through extensive experimental research, it has been found that the initial state of the soil sample, the properties of the soil sample, the size of the soil sample, the thickness of the soil layer, the soil composition, environmental temperature, relative humidity, contact conditions between the sample and container, and the number of dry-wet cycles all have important effects on the evaporation and cracking of soils [19][20][21][22][23]. Although important research results have been obtained in the field of soil evaporation and cracking, it can be seen that previous studies have mainly focused on uncontaminated soils, and there have been relatively few studies on the evaporation and cracking of contaminated clay, especially on those contaminated by organic contaminations from domestic sources. ...
In arid climates, evaporation and water loss in surface soil can lead to the development of shrinkage cracks in the soil. The crack network in contaminated soil sites can become a rapid pathway for the infiltration and transport of contaminations, thereby increasing the range of soil contamination. Dense contaminated clay samples were prepared by using glucose as a representative soluble sugar of domestic source contaminations. Through indoor evaporation simulation tests, the effect of soluble sugar anaerobic degradation on the water loss, deformation, and crack growth of compacted clay was analyzed, and the mechanism of this effect was revealed. The results showed that glucose increased the water-holding capacity of clay, while the anaerobic degradation of glucose decreased the water-holding capacity of clay. Although glucose anaerobic degradation reduced the overall deformation of dense clay, it promoted the development of evaporative cracks on the surface of dense clay. Soluble sugar anaerobic degradation mainly affected the evaporative cracking of clay by “forming hydrogen bonds to reduce the rate of evaporative water loss in clay” and “generating CO2 to alter the structure of the clay”.
... A systematic sampling approach was employed to collect random samples at several sampling sites located in northern Malaysia over the period of December to March 2021, which corresponds to the hot and dry season. The rise in temperature and wind velocity during this period creates favourable conditions for sampling due to the natural evaporation of soil moisture, which results in the concentration of residual nutrients within the soil [16,17]. Every soil sample is securely enclosed within a plastic bag and appropriately labelled with precise details like the time, date, and specific location. ...
The relationship between NIR spectroscopy spectral absorbance and potassium (K) is studied as a representative factor for analysing soil's nutritional content. To determine the potassium content of soil samples without resorting to intrusive and time-consuming chemical analysis techniques, NIR spectroscopy sampling techniques have been tested. Spectrum absorption data from 900 nm to 1600 nm were discovered to correspond with potassium values and were then analysed using a number of pre-processing procedures. Five techniques, Multiplicative Scatter Correction (MSC), Multiplicative Scatter Correction using Common Amplification (MSSCA), Multiplicative Scatter Correction using Common Offset (MSCCO), Detrending (DT), and Mean Normalization (MN), have been identified as the most effective. Using the Partial Least Squares Regression (PLSR) model, both calibration and prediction data are evaluated. In the end study, the MSCCA method was determined to be the most effective pre-processing method for both calibration and prediction outcomes, with R2 values of 0.9998 for calibration and RMSE values of 0.0600 for prediction. Utilising PLSR model and the MSCCA preprocessing method, the relationship between NIRS absorbance data and potassium may be determined. Consequently, we may infer that the NIRS approach can be utilised to detect amount of potassium in soil analysis employing a less time-consuming, non-invasive, and labour-intensive sampling technique.
... These fractions' physical, chemical, and mineralogical characteristics differ significantly from one another. The term "soil texture" refers to their relative distribution in a soil [20,21]. One of the most crucial physical characteristics of soil that influences its fertility and production is its texture [22]. ...
... Soil water evaporation is more complicated than pure water evaporation, due to the multi-component composition and variability in the evaporation process. In addition, soil evaporation involves environmental conditions: temperature, radiation, humidity and wind speed, which affect the potential rate of evaporation (Gilliland, 1938;Yamanaka et al., 1997;Song et al., 2014;Poulsen et al., 2020); and soil characteristics: moisture, suction, texture, pore distribution and dense degree, which affect hydraulic conductivity and vapor diffusivity and further affect moisture migration (Tang et al., 2011a;Teng et al., 2016;An et al., 2018c;Song et al., 2018). There are three conditions required for the occurrence and maintenance of soil evaporation as demonstrated by Hillel (1980): (1) sufficient heat to meet the consumption of latent heat of evaporation; (2) the gradient of vapor pressure between evaporation surface and atmosphere; (3) continuous water supply to sustain evaporation. ...
... In order to better understand the mechanism of soil water evaporation, a number of experiments and apparatus have been carried out. For instance, soil evaporation is directly measured by sensitive weighing scales for small-sized soil samples and by weighing lysimeters for large scale filed investigations (Wilson, 1990;Qiu et al., 1998;Benli et al., 2006;An et al., 2018c;Zeng et al., 2022). A wind tunnel system is developed to investigate the influence of environmental conditions on soil evaporation (Komatsu, 2003;Yamanaka et al., 2004;Yuge et al., 2005). ...
... Finally, they reach the residual stage of water evaporation, which is characterized by a significantly low evaporation rate approaching zero, due to the powerful adsorption of water by clay particles. The similar three-stage evolution of soil evaporation rate was also obtained by previous researches (Tang et al., 2011b(Tang et al., , 2021An et al., 2018c;Zeng et al., 2022). Fig. 11 presents volumetric water content distribution in different segments with a constant RH of 0.3 at t = 8 days. ...
Cracking is a common phenomenon in clayey soils under soil-atmosphere interaction. It strongly promotes water evaporation and further affects thermo-hydro-mechanical behavior and engineering properties of soils. In this study, a new numerical approach is proposed to simulate water evaporation in cracked soils. The new approach divides the cracked soil into two domains: the soil domain follows a coupled hydro-thermal approach and the air domain follows Fick’s law. The boundary conditions of the two domains are identified by the vapor flux with a suction-related evaporation model. Two sets of numerical tests are performed to examine the effects of air humidity and segmentation method on soil evaporation rate and volumetric water content profile versus time. Results reveal that soil water content near soil surface and soil crack surface decreases more rapidly. The more segments of crack surface are conducted, the more realistically it can reflect the variation of crack surface evaporation in depth, but it will increase the computational burden. Air humidity does affect the rate of evaporation and the larger the relative humidity, the lower evaporation rate. Furthermore, the presented numerical approach provides a benchmark for a satisfactory description of water evaporation from a clayey soil with cracks.
... After 1200 min, the moisture content tended to stabilise, with a residual moisture content of 0.5%. An earlier study by An et al. [37] on the moisture content curve of clay slurry samples of different thicknesses obtained similar results, albeit with a different residual moisture content due to differences in soil properties and external temperature conditions. ...
... After 1200 min, the moisture content tended to stabilise, with a residual moisture content of 0.5%. An earlier study by An et al. [37] on the moisture content curve of clay slurry samples of different thicknesses obtained similar results, albeit with a different residual moisture content due to differences in soil properties and external temperature conditions. time were obtained. ...
... After 1200 min, the moisture content tended to stabilise, with a residual moisture content of 0.5%. An earlier study by An et al. [37] on the moisture content curve of clay slurry samples of different thicknesses obtained similar results, albeit with a different residual moisture content due to differences in soil properties and external temperature conditions. As shown in Figures 2-4, there were no significant changes in the curv length, average crack width, and crack ratio before 270 min. ...
Red clay is susceptible to cracking in desiccating environments, with resulting crisscrossing cracks that compromise the soil structure and increase the likelihood of geological hazards. To investigate the dynamic mechanism of the initiation and propagation of soil desiccation cracks under natural hygrothermal conditions, a desiccation test was conducted on a red clay slurry using three-dimensional digital image correlation (3D DIC) technology. The evolution behaviour of desiccation cracks was analysed, and the dynamic relationships between moisture content, displacement field, strain field, and soil desiccation cracking were explored. The test results showed that the Atterberg limits of red clay are correlated with desiccation cracking. Cracks tend to initiate in areas where tensile strain is concentrated or significant displacement differences exist. Following crack initiation, the surrounding strain and displacement fields redistribute, influencing the propagation direction, development rate, and morphology of subsequent cracks nearby. Additionally, the relative displacement and strain at the edges of cracks are related to the crack propagation direction. Earlier crack initiation usually corresponds to a larger relative displacement and strain at the crack edges, while the displacement and strain at the soil clod centre are typically smaller than those at the crack edges. DIC technology can quickly and accurately obtain dynamic information about displacement and strain fields, providing feasible technical support for analysing the dynamic mechanism behind soil desiccation cracking. It has potential value in engineering hazard prevention and sustainable development.
