Water Redistribution Research Articles

Influence of Moisture Regime on the Redistribution of Radioactive Cesium and Strontium Isotopes in Alluvial Soils by Physico-Chemical Forms

The transformation of the hydrological regime of floodplains due to climate change and anthropogenic impact on water redistribution processes within natural landscapes can significantly impact the bioavailability of long-lived radioactive isotopes of cesium and strontium. A laboratory experiment demonstrated that varying the moisture content of alluvial soil within 40–100% from its full water-holding capacity leads to the redistribution of ¹³⁷Cs and ⁹⁰Sr between different chemical forms. Soil saturation with water increases the proportion of water-soluble ¹³⁷Cs, while the proportion of water-soluble ⁹⁰Sr decreases. The ion-exchangeable form of ¹³⁷Cs remains unaffected by soil moisture. The behavior of the ion-exchangeable form of ⁹⁰Sr in response to changes in soil moisture is dependent on soil characteristics: a significant increase in the proportion of ⁹⁰Sr was observed in sod-gley soil developed on sandy alluvium as soil moisture increased; however, this phenomenon was not observed in sod-gleyed soil developed on loamy alluvium. The proportion of ¹³⁷Cs extracted by sodium tetraphenylborate increases when alluvial soils are saturated with water. Similarly, the mobile form of ⁹⁰Sr behaves in the same manner, but when soil moisture reaches 100% of its full water-holding capacity in sod-gley soil, a sharp decrease in the proportion of the mobile form of this radionuclide is observed. Overall, there is a trend towards increased proportions of bioavailable forms of ¹³⁷Cs and ⁹⁰Sr in alluvial soils with increased moisture content, although the pecularities and magnitude of this phenomenon depend on the specific soil characteristics.

Rethinking the impact of water-saving technologies and market incentives: lessons from Mercy Corps’ water innovation technologies program

Abstract In the face of unrelenting water crises, water-saving technologies are increasingly relied upon as a paradigm for managing scarce water resources in the agricultural sector. This approach is gaining momentum in international forums and among development practitioners focused on improving the sustainability and efficiency of their water security interventions. Following this trend, the integration of market incentives to foster the uptake of water-saving technologies (WSTs) is not surprising. However, recent literature on water-saving technologies and related incentives paints an ambiguous picture of the impact these technologies can have. On one hand, there is evidence that supports the efficacy of market incentives in promoting water-saving practices and the adoption of WSTs. On the other hand, there are also concerns about the potential adverse consequences of introducing WSTs, including promoting unsustainable water consumption and exacerbating inequalities. This study focuses on Mercy Corps’ Water Innovation Technologies program in Jordan, a country grappling with severe water scarcity. It specifically examines how market mechanisms played a crucial role in saving approximately 24 million cubic meters of water, equivalent to around 9,500 Olympic-sized swimming pools. Driven by this significant achievement, the study delves deeper into the efficacy of market-based approaches, while also considering their potential limitations. The conclusion offers a critical perspective on how the promotion of WST through market-based approaches can ensure that water savings contribute to both environmental sustainability and human well-being. In particular, Mercy Corps' practitioner perspective advocates for governance reforms that limit and prevent unsustainable consumption, facilitate and ensure equitable access to WSTs, and promote the fair redistribution of water savings across different users.

Impacts of zein-fucoidan nanoparticles with and without curcumin on gel properties of golden threadfin bream (Nemipterus virgatus) surimi.

Zein-fucoidan nanoparticles (ZFNPs) as an excellent colloidal delivery system for bioactive compounds, such as curcumin (CUR), show a great application potential in the food industry. Herein, various amount of ZFNPs, ZFNPs loaded with CUR (CZFNPs) and free CUR were added into golden threadfin bream (Nemipterus virgatus) surimi to explore their impacts on the gel properties. Dynamic rheological tests showed that storage modulus (G') and loss modulus (G") of surimi gels with the additive amount of ZFNPs and CZFNPs under 0.8% significantly increased and their loss tangent (tan δ) slightly reduced during thermal gelation, indicating stronger networks and better structural configuration. Puncture test and textural profile analysis confirmed the improvements in breaking force, hardness, chewiness and gumminess of surimi gels. Furthermore, 0.8% of ZFNPs and CZFNPs induced conformational changes of surimi proteins from α-helix to β-sheet and random coil, and then facilitating the cross-link between proteins. Low-field nuclear magnetic resonance revealed that ZFNPs and CZFNPs promoted the redistribution of water in surimi gel networks, converting more free water to tightly bounded water, and thus increasing the water holding capacity. However, the addition of equivalent amount of CUR caused detrimental to surimi gel properties. In conclusion, ZFNPs and CZFNPs conferred better gel properties and nutritional characteristics to surimi gels, and this study provided a theoretical basis for the development of high-quality surimi products.

The Effect of Drink Containing Harvest on Body Water Redistribution After Dehydration-Inducing Exercise

The Effect of Drink Containing Harvest on Body Water Redistribution After Dehydration-Inducing Exercise

INFLUENCE OF FIRECLAY GRANULES ON CALCIUM ALUMINATE CEMENT HYDRATION AND PROPERTIES AFTER FIRING

The article investigates the effect of granules, produced from dispersive fireclay using liquid glass as a binder, on the hydration process of calcium aluminate cement (CAC). Peculiarities of the hydration process were evaluated from the results of calorimetry, thermal analysis, XRD, SEM, and mechanical properties tests, as well as the relative viscosity of the cement pastes. It is determined that the granules are capable of entrapping water and releasing it later, shortening the incubation period and increasing the maximal heat release rate during the CAC crystallization stage and total cumulative heat as compared with the control samples with the same active cement part and containing dispersive fireclay particles, which are cement-inert. The redistribution of water due to granules’ addition results also in more hydrates C2AH8 and AH3 in CAC pastes containing granules than in those containing dispersive fireclay. Due to the reaction between the water solution containing dissolved cement minerals and sodium silicate film (dried liquid glass), the hydrogel-like phases form inside the granule during the hydration, which fill the gaps between the fireclay particles and after firing at 1100 °C form a glassy phase enveloping the fireclay particles and binding them to each other, providing the granule integrity and contributing to their strength. The specific structure formed due to the addition of fireclay granules does not change dramatically the density of the obtained composite, provides 7.4–18.5% higher strength after drying with 7.5–15% granule addition and ∼11% higher strength after sintering at 1100 °C with 5% granule addition (as compared with compositions containing dispersive fireclay). 30% granule addition can be considered as too much, causing significant strength loss.

Soil moisture and water redistribution patterns in white oak (Quercus alba) saplings and trees in fragmented urban woodlands

In the midwestern United States, models predict extended summer heatwaves and increasingly frequent and prolonged drought conditions. In the Chicago region, the potential for large-scale mortality of white oak trees (Quercus alba) coupled with the ongoing decline of white oak sapling recruitment are major concerns for researchers and practitioners. In this study, we determined the sources of water used by mature white oak trees and saplings in three qualitatively different sites within a remnant oak forest in Chicago during the 2021 drought. We investigated soil moisture dynamics (volumetric water content, VWC) and water isotope composition of leaf tissues (δD, δ18O), rainwater, and groundwater. These data were linked to sapling height (proxy for biomass) and ectomycorrhizal (ECM) functional types. We predicted that: (i) mature oak trees use deeper water sources and conducted hydraulic redistribution (HR), and (ii) mature trees shared water with saplings during dry periods via long-distance ECM functional types. Soil moisture decreased progressively from June to October (spring to fall), with August and September having the lowest moisture (<20 % VWC). Following rainfall recharge, temporal patterns of soil moisture showed gravity drainage and then ongoing stair-stepwise drawdown consistent with plant evapotranspiration. Leaf δD and δ18O values in mature trees and saplings were consistent with water uptake from rainfall and subsequent enrichment via evapotranspiration. In two sites, mature trees and saplings demonstrated distinct δD: δ18O slopes, with mature trees more enriched than saplings. In the third site, mature trees and saplings δD: δ18O slopes overlapped but here, the ECM community was dominated by contact-type ECM and sapling height increased with distance from the mature oak. Our findings indicate that HR was not a component of site ecohydrology, and future climate conditions may present increasing challenges for white oak recruitment as both mature trees and saplings compete for limited rainfall-derived soil moisture.

New insights on the basic creep mechanism of one-part alkali activated slag and fly ash paste

In this paper, basic creep mechanism of ambient cured one-part alkali activated slag-fly ash (AASF) paste is examined at the microscopic level. A special mini creep rig is constructed enabling in-situ monitoring of water redistribution over time between high- and low-density (HD, LD) gel pores within the loaded paste specimens using 1H NMR relaxometry. The results suggest that the contraction of C-(N)-A-S-H particles is accompanied by the reduction of water content in HD gel for loaded AASF paste. In contrast, in the loaded OPC paste a noticeable decrease of water residing in LD rather than HD C-S-H gel was observed, implying the presence of a distinct creep mechanism. In addition to the different water environment, the more crosslinked bonding structure of AASF could partially account for its lower creep response supported by 29Si NMR measurement. The findings of this study provide evidence in understanding underlying basic creep mechanism of AASF.

Evaluation of stakeholder knowledge and practices of water use management strategy: Observations from a questionnaire survey in Southern India

Freshwater resources remain unequally distributed in time and space around the world. Water resource frameworks should be designed, planned, and overseen in order to fully meet current and future social and economic objectives. The difficulties grow as the system gets bigger and more complex, with varying spatial distribution of water and insufficient resources, making water re-distribution more difficult. The current study fills such gaps by evaluating several factors influencing conjunctive management. In the current study, an effort has been made to compile the best data on water use, agricultural practises, socioeconomic status, and so on through field surveys in order to comprehend the reality on the ground. Additionally, investigations are being conducted into the causes and barriers that are most likely to have slowed the implementation of conjunctive use of available water resources. Two comprehensive socioeconomic surveys were conducted using the quantitative research methodology in a river basin in Southern India, and the results clearly show that stakeholders are unaware of the most effective agricultural water management techniques and the rationale behind modern irrigation systems. Over ninety-five percent of the total respondents were farmers, with only five percent having basic knowledge of watershed development and conjunctive use water management. The identified gaps and the inference made in the study are in the context of conjunctive water management of agricultural water. The current work may provide useful information on the baseline scenarios for upcoming agricultural water management plans, as well as a useful tool for achieving significant milestones in the agricultural sector. Furthermore, the prepared questionnaire and the data gathered for the study may also be helpful to decision-makers.

Effects of Xerophytic Vegetation-Salix on Soil Water Redistribution in Semiarid Region

Xerophytic vegetation re-regulates and allocates water resources through canopy interception, root water uptake and transpiration, and changes the water budget among precipitation, runoff, interception and infiltration, thus having a significant impact on the processes of the hydrological cycle. In this study, we investigated the effect of xerophytic shrub-Salix on soil water redistribution and water budget through an in situ monitoring experiment combined with two-dimensional vegetation water consumption modeling. The results showed that, due to the interception effect of root water uptake, it was difficult for precipitation infiltration to recharge deep soil water and groundwater. The measured data of soil moisture content, hydraulic head and precipitation were used to verify and calibrate the performance of the soil water flow model in the vadose zone by HYDRUS-2D. The effect of roots system on soil water was simulated, and the appropriate spacing of Salix replanting was estimated. Combined with the relationship between the transverse roots system and the crown width obtained by the investigation, it was determined that the spacing between the Salix should be greater than five times the crown width, so that the balance between the water consumption of Salix and the water supply of deep soil by precipitation could be considered. The results of this study are important for estimating groundwater recharge in arid areas and provide practical vegetation replanting options for similar regions.

Feedback mechanisms controlling Antarctic glacial-cycle dynamics simulated with a coupled ice sheet–solid Earth model

Abstract. The dynamics of the ice sheets on glacial timescales are highly controlled by interactions with the solid Earth, i.e., the glacial isostatic adjustment (GIA). Particularly at marine ice sheets, competing feedback mechanisms govern the migration of the ice sheet's grounding line (GL) and hence the ice sheet stability. For this study, we developed a coupling scheme and performed a suite of coupled ice sheet–solid Earth simulations over the last two glacial cycles. To represent ice sheet dynamics we apply the Parallel Ice Sheet Model (PISM), and to represent the solid Earth response we apply the 3D VIscoelastic Lithosphere and MAntle model (VILMA), which, in addition to load deformation and rotation changes, considers the gravitationally consistent redistribution of water (the sea-level equation). We decided on an offline coupling between the two model components. By convergence of trajectories of the Antarctic Ice Sheet deglaciation we determine optimal coupling time step and spatial resolution of the GIA model and compare patterns of inferred relative sea-level change since the Last Glacial Maximum with the results from previous studies. With our coupling setup we evaluate the relevance of feedback mechanisms for the glaciation and deglaciation phases in Antarctica considering different 3D Earth structures resulting in a range of load-response timescales. For rather long timescales, in a glacial climate associated with the far-field sea-level low stand, we find GL advance up to the edge of the continental shelf mainly in West Antarctica, dominated by a self-amplifying GIA feedback, which we call the “forebulge feedback”. For the much shorter timescale of deglaciation, dominated by the marine ice sheet instability, our simulations suggest that the stabilizing sea-level feedback can significantly slow down GL retreat in the Ross sector, which is dominated by a very weak Earth structure (i.e., low mantle viscosity and thin lithosphere). This delaying effect prevents a Holocene GL retreat beyond its present-day position, which is discussed in the scientific community and supported by observational evidence at the Siple Coast and by previous model simulations. The applied coupled framework, PISM–VILMA, allows for defining restart states to run multiple sensitivity simulations from. It can be easily implemented in Earth system models (ESMs) and provides the tools to gain a better understanding of ice sheet stability on glacial timescales as well as in a warmer future climate.

Effect of wheat flour particle size on the quality deterioration of quick-frozen dumpling wrappers during freeze-thawed cycles

To reveal the effect of wheat flour particle size on the quality deterioration of quick-frozen dumpling wrappers (QFDW) during freeze-thawed (F/T) cycles, the components and physicochemical properties of wheat flours with five different particle sizes were determined and compared, along with the changes in texture and sensory properties, water status, and microstructure of QFDW during F/T cycles. Results showed that as particle size decreased, the damaged starch content and B-type starch content increased, the water absorption increased, and the gluten strength decreased. Furthermore, F/T cycles negatively impacted the quality of QFDW, evidenced by decreased texture properties and sensory evaluation score, water redistribution, higher freezable water content, and disruption of gluten network. Notably, QFDW made from larger particle size wheat flours required the shortest duration when traversing the maximum ice crystal formation zone. The QFDW made from larger particle size wheat flours formed a more stable starch-gluten matrix, which resisted the damage caused by ice recrystallization, demonstrating better water binding capacity and F/T resistance. The results may provide theoretical guidance for the study of QFDW quality and the moderate processing of wheat flour in actual production.

Contribution of yeast freezing to the quality of frozen dough: Rheological properties, protein depolymerization, gluten conformation and water state

The present study has comparatively investigated the variation in yeast leachates in frozen suspension and dough systems and assessed the effects of leachate released from frozen yeast cells on dough rheology, protein molecular weight distribution, gluten conformation, and water state. The results revealed that yeast in the dough was more susceptible to freezing than that in the suspension and released more low-molecular-weight metabolites (e.g., trehalose, glutathione, and amino acids) into the dough matrix. Dynamic rheological measurements showed that frozen yeasted dough had weaker viscoelastic properties than non-yeasted dough. Fourier transform infrared spectroscopy revealed a high fraction of β-turns and random coils at the expense of α-helices and β-sheets, demonstrating a flexible protein secondary structure and increase in weakened hydrogen bonds in the gluten network. The presence of yeast in the frozen dough facilitated dough depolymerization via the cleavage of interchain disulfide bonds of gluten protein and softened the gluten network structure. Yeast leachates released from frozen yeast cells caused water redistribution in the dough and increased water release from the weakened gluten network, increasing freezable water content. This study has revealed the essential role of yeast freezing in gluten depolymerization and the deterioration of dough quality.

Effect of exogenous protein substitution in glutinous rice cake: Batter rheology, structure, and retrogradation behavior

The investigation focused on the batter properties, baking performance, and retrogradation behavior of gluten-free sponge cakes after partial (15%, 30%, and 45%) substitution of glutinous rice flour with exogenous protein, including whey protein isolates (WPI), egg white protein (EWP), and soy protein isolate (SPI). The viscoelastic properties and apparent viscosity of batter positively correlated with substitution levels, with SPI superior to WPI and EWP. WPI could produce batter with smaller and more evenly distributed cells, contributing to an enhanced specific volume of the cake due to its stabilizing effect of gas cells to form viscoelastic films. The gelatinization of starch granules proved to be constrained by the incorporation of WPI and SPI, as evidenced by elevated gelatinization temperature and reduced enthalpy change values. The restriction could be attributed to the strengthened hydrogen bonding between the starch and protein, which subsequently alleviated the retrogradation and water redistribution of cake during storage. An unpleasant eggy or beany flavor of cake was generated at 45% substitutions of EWP and SPI. In comparison, 30% WPI contributed to an appealing aroma and mouthfeel, making it a nutritional supplement to enhance its protein content while maintaining its fine sensory attributes of gluten-free sponge cake.

Assessment of environmental impact of road construction based on results of remote sensing monitoring

Remote sensing detected the impact of road construction on important environmental properties. The digital elevation model was applied to assess the impact of road construction on environmental regimes. The study focused on the total area of the 3-km zone of influence (monitoring zone of probable impact) around the national road H-31 Dnipro-Tsarychanka-Kobeliaky-Reshetylivka from Loboikivka village to the boundary of Dnipropetrovsk Oblast. The following derivatives of the digital elevation model are considered as geomorpho­logical variables: the topographic wetness index (TWI) and erosion factor (LS). To model the effect of road construction on the moisture regime and dynamics of erosion processes, the TWI and LS indices were calculated for a digital terrain model without a road and with a road with an elevation that corresponds to the planned level. Thus, the road is considered as an anthropogenic landform that changes the direction of water redistribution along the topography and thus affects the potential moisture conditions and erosion risks. The modeling results indicate that the transformation of the water regime will be observed within the entire 3-km monitoring area. Deviations from the normal value can be up to 7 units by module, which is about one third of the landscape-wide range of topographic moisture index values. Almost no impact of construction can be predicted for 80.7% of the territory. For 10.6% of the territory, the increase in moisture regime will be moderate, and for 3.2% of the area the increase will be very significant. In turn, for 4.3% of the area the decrease in humidification will be moderate, and for 1.2% the decrease will be very significant. The greatest impact on the redistribution of moisture conditions is predicted in the immediate vicinity of the road. Changes in the moisture regime can have significant negative consequences for both soil cover and biotic components of ecosystems. Changes in vegetation as a consequence of changes in both moisture and trophic conditions can be considered as possible scenarios for the development of landscape cover dynamics.

Tree species explain only half of explained spatial variability in plant water sensitivity.

Spatiotemporal patterns of plant water uptake, loss, and storage exert a first-order control on photosynthesis and evapotranspiration. Many studies of plant responses to water stress have focused on differences between species because of their different stomatal closure, xylem conductance, and root traits. However, several other ecohydrological factors are also relevant, including soil hydraulics, topographically driven redistribution of water, plant adaptation to local climatic variations, and changes in vegetation density. Here, we seek to understand the relative importance of the dominant species for regional-scale variations in woody plant responses to water stress. We map plant water sensitivity (PWS) based on the response of remotely sensed live fuel moisture content to variations in hydrometeorology using an auto-regressive model. Live fuel moisture content dynamics are informative of PWS because they directly reflect vegetation water content and therefore patterns of plant water uptake and evapotranspiration. The PWS is studied using 21,455 wooded locations containing U.S. Forest Service Forest Inventory and Analysis plots across the western United States, where species cover is known and where a single species is locally dominant. Using a species-specific mean PWS value explains 23% of observed PWS variability. By contrast, a random forest driven by mean vegetation density, mean climate, soil properties, and topographic descriptors explains 43% of observed PWS variability. Thus, the dominant species explains only 53% (23% compared to 43%) of explainable variations in PWS. Mean climate and mean NDVI also exert significant influence on PWS. Our results suggest that studies of differences between species should explicitly consider the environments (climate, soil, topography) in which observations for each species are made, and whether those environments are representative of the entire species range.

The influence of hillslope topography on beech water use: a comparative study in two different climates

Abstract. Understanding the interrelation between topography and vegetation across different environments is important to assess how hydrological and climatic conditions affect tree physiological activity. This becomes especially important given the expected reduction in water availability and the increase in water demand driven by climate change. These extremes could enhance the thermal and hydrologic gradients along slopes. Here, we aimed to test if and how different climatic and hydrological conditions affect the physiological response of beech trees (Fagus sylvatica L.) to environmental variables along two different topographic sequences. For this purpose, we set up a comparative study on a gentle hillslope in the Weierbach catchment in Luxembourg (oceanic climate) and on a steep hillslope in the Lecciona catchment in Italy (Mediterranean climate). We combined sap velocity measurements with isotopic measurements of soil, precipitation, stream water, groundwater, and xylem over 2019 and 2020 for the Luxembourgish site and over 2021 for the Italian site. We found that, in the Weierbach catchment, trees' responses to environmental variables (i.e. vapour pressure deficit and relative extractable water in the soil) were similar among hillslope positions and between the two monitored years, resulting from homogeneous growing conditions along the topographic sequence. We also did not find any statistical difference in the isotopic composition of xylem water between positions, suggesting that beech trees relied on similar water sources across the landscape. In the Lecciona catchment, we observed lower sap velocities and shorter growing season in trees growing in the upper portions of the hillslope, likely related to water redistribution and different soil moisture along the hillslope catena. Xylem isotopic composition was significantly lighter at the footslope location throughout the growing season than in the upslope locations, suggesting location-specific water use. These results emphasize how differing hydrometeorological processes occurring at the hillslope scale can lead to contrasting tree responses.

Distinct variations of soil infiltrability of contrasting root types in a temperate mosaic-pattern grassland in northern China

Soil infiltration capacity is an important factor affecting soil moisture, and is of great significance to plant growth and groundwater recharge in arid and semiarid areas. Patchiness of grasslands widely exist and have a crucial effect on hydrological processes in water-limited regions. This study investigated soil infiltrability under natural grasslands with patchy mosaic patterns based on a series of in-situ tests. Two dominated natural restoration vegetation communities (Bothriochloa ischaemum (B. ischaemum) with fibrous root systems and Artemisia gmelinii (A. gmelinii) with tap root systems) and abandoned land (as control) were selected in the loess hilly and gully region of the Loess Plateau, China. The results showed that natural restoration grasslands significantly improved soil infiltrability in both plant and bare patches, and the emergence of patchy mosaic patterns can result in infiltration heterogeneity to redistribute water on a hillslope scale. Compared to B. ischaemum, A. gmelinii are more likely to facilitate the formation of preferential flow, contributing to the increased soil infiltration rates. The initial, steady and average infiltration rates (IIR, SIR, and AIR, respectively) and soil infiltration capacity index (SIC) were all negatively correlated with both root length density (RLD) and root surface area density (RSAD) of fine roots (diameter < 2 mm) but positively correlated with those of coarse roots (diameter ≥ 2 mm). The main factors influencing the infiltration capacity were the mean weight diameter in the 10−20 cm layer and the RSAD of the fine roots in the 0−20 cm layer, which can explain 98.6 %, 81.7 %, 63.9 %, and 91.3 % of the total variance of IIR, SIR, AIR, and SIC, respectively. This work highlights the important roles of patchy mosaic patterns in affecting soil water redistribution and the stabilization of ecological systems, providing a scientific basis for vegetation selection in the process of vegetation restoration in water-limited regions.

Distribution and Variation of Soil Water and Salt before and after Autumn Irrigation

Autumn irrigation is a key measure for alleviating soil salinity and promoting sustainable agricultural development in the Hetao Irrigation district; however, only a part of farmland is irrigated in autumn during the non-growth period of crops, which leads to the redistribution of soil water and salt between autumn-irrigated land (AIL) and adjacent non-autumn-irrigated land (NAIL) after autumn irrigation. To explore the distribution and variation of soil water and salt in different positions of AIL and NAIL after local autumn irrigation and reveal the interaction range between AIL and NAIL, field experiments were carried out for two years in typical test areas. The results showed that compared with non-autumn irrigation, autumn irrigation improved the distribution uniformity of soil water and salt profiles in both horizontal and vertical directions; after autumn irrigation, the water content of the soil at the nearest sampling point to the boundary in the AIL increased the least, but the desalination rate was the greatest, while the water and salt contents of the soil within 45 m from the sampling points to the boundary in the NAIL both increased significantly. NAIL received the drainage of AIL and made the groundwater level after the rise in AIL fell quickly back, but unreasonable autumn irrigation caused the groundwater level of AIL to remain at a high level before freezing, exacerbating the risk of groundwater carrying salts to the surface soil during the freezing and thawing period, detrimental to the growth of crops in the next spring. The research results are of great significance to the rational use of farmland water resources and the improvement of soil salinization in cold and dry areas.

Microtopography effects on pedogenesis in the mudstone-derived soils of the hilly mountainous regions

Topography is a critical factor that determines the characteristics of regional soil formation. Small-scale topographic changes are referred to microtopographies. In hilly mountainous regions, the redistribution of water and soil materials caused by microtopography is the main factor affecting the spatial heterogeneity of soil and the utilization of land resources. In this study, the influence of microtopography on pedogenesis was investigated using soil samples formed from mudstones with lacustrine facies deposition in the middle of the Sichuan Basin. Soil profiles were sampled along the slopes at the summit, shoulder, backslope, footslope, and toeslope positions. The morphological, physicochemical, and geochemical attributes of profiles were analyzed. The results showed that from the summit to the toeslope, soil thickness increased significantly and profile configuration changed from A–C to A–B–C. The total contents of Ca and Na decreased at the summit, backslope, and footslope, while the total contents of Al, Fe and Mg showed an opposite trend. On the summit and shoulder of the hillslope, weathered materials were transported away by gravity and surface erosion, exposing new rocks. As a result, soil development in these areas was relatively weak. In flat areas such as the footslope and toeslope with sufficient water conditions, the addition of weathered components and the prolonged contact between water, soil, and sediment led to further chemical weathering, resulting in highly developed characteristics. Microtopography may influence physicochemical properties, chemical weathering, and redistribution of water and materials, causing variations in pedogenic characteristics at different slope positions.

Recovery characteristics of reversible degradation for proton exchange membrane fuel cell stack under accelerated stress test

The reversible degradation of proton exchange membrane fuel cells (PEMFC) restricts the high efficiency and long-term durability of fuel cells. The reversible loss, restorable only through specific procedures, significantly diminishes both the operational efficiency and the predictability of their remaining service life. Consequently, it is imperative to elucidate the recovery characteristics of reversible loss in high power PEMFC stacks for engineering applications. However, most of the studies focus on small-area single cells or short stacks, researches on the full-size stacks considering the uniformity and consistency differences are scarce. The recovery characteristics of high-power PEMFC stacks remain unclear. Therefore, in this work, an accelerated stress test with the idle and rated currents as the boundary of the cyclic condition was designed for a 100 kW PEMFC stack to investigate the recovery characteristics. The periodic voltage fluctuations along with the shutdown operations indicate that the voltage recovery may be caused by the redistribution of water content within the stack, and the reversible degradation is more pronounced and readily reversible under the high current condition. The impedance results suggest that the redistribution of water within the catalyst layer takes longer compared to that in the membrane. Furthermore, analyses of single cell voltage indicate that the consistency of voltage recovery is more closely related to variations of water content within the catalyst layer. Cells with higher water content exhibit better voltage recovery.