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Abstract: Quantifying evapotranspiration (ET) is critical to accurately predict vegetation health, groundwater recharge, and streamflow generation. Hillslope aspect, the direction a hillslope faces, results in variable incoming solar radiation and subsequent vegetation water use that drive ET. Previous work in watersheds with a single dominant vegetation type (e.g., trees) have shown that equator‐facing slopes (EFS) have higher ET compared to pole‐facing slopes (PFS) due to higher evaporative demand. However, it remains unclear how differences in vegetation type (i.e., grasses and trees) influence ET and water partitioning between hillslopes with opposing aspects. Here, we quantified ET and root‐zone water storage deficits between a PFS and EFS with contrasting vegetation types within central coastal California. Our results suggest that the cooler PFS with oak trees has higher ET than the warmer EFS with grasses, which is counter to previous work in landscapes with a singule dominant vegetation type. Our root‐zone water storage deficit calculations indicate that the PFS has a higher subsurface storage deficit and a larger seasonal dry down than the EFS. This aspect difference in subsurface water storage deficits may influence the subsequent replenishment of dynamic water storage, groundwater recharge and streamflow generation. In addition, larger subsurface water deficits on PFS may reduce their ability to serve as hydrologic refugia for oaks during multi‐year droughts. This research provides a novel integration of field‐based and remotely‐sensed estimates of ET required to properly quantify hillslope‐scale water balances. These findings emphasize the importance of resolving hillslope‐scale vegetation structure within Earth system models, especially in landscapes with diverse vegetation types.

We demonstrate an indirect, rather than direct, role of quasi-resonant amplification of planetary waves in a summer weather extreme. We find that there was an interplay between a persistent, amplified large-scale atmospheric circulation state and soil moisture feedbacks as a precursor for the June 2021 Pacific Northwest "Heat Dome" event. An extended resonant planetary wave configuration prior to the event created an antecedent soil moisture deficit that amplified lower atmospheric warming through strong nonlinear soil moisture feedbacks, favoring this unprecedented heat event.

Irrigation is vital for Philippine agriculture, particularly in regions like Bohol, where water resources are under pressure due to competing demands and seasonal droughts. Despite introducing automated irrigation technologies designed to enhance efficiency, many areas still need to rely on updated manual methods, leading to water wastage and reduced productivity. This study explores the potential of automated irrigation systems to improve water use efficiency by evaluating soil's physical and electrical properties in Bohol's greenhouses. Specifically, it investigates soil texture, bulk density, pH, moisture content, and the performance of resistive and capacitive soil moisture sensors under varying conditions. Using a randomized complete block design, the research analyzed soil samples from greenhouses in six municipalities: Antequera, Bilar, Calape, Carmen, Jagna, and Loay. Laboratory experiments assessed soil properties, and a custom Arduino-based soil moisture meter was developed for sensor calibration. The study found significant variability in soil properties across locations, with sandy clay loam soils exhibiting the highest electrical resistivity and lower water retention than silty clay and clay soils. The findings highlight that soil pH varied from slightly basic to strongly acidic, and sensor voltage output inversely correlated with soil moisture content, reflecting changes in electrical conductivity. The results underscore the importance of selecting appropriate sensors and calibration methods for accurate soil moisture measurement. Recommendations include further testing for sensor variability, preference for capacitance over resistive sensors, and rigorous calibration procedures. Enhancing these practices will improve the effectiveness of automated irrigation systems and support sustainable agricultural development in Bohol. [ABSTRACT FROM AUTHOR]

Synthetic Aperture Radar (SAR) is a potent instrument for estimating soil moisture across vast farmland areas. However, when soil salinity rises, existing SAR retrieval models for soil moisture become less accurate. Soluble salts in soil water alter the inherent correlation between the SAR backscattering coefficients and soil water, thus compromising the performance of retrieval models. The need to get surface roughness parameters from the field also limits the widespread application of the model. To address these issues, we developed a retrieval model for salty soil moisture assessment under small-scale roughness surfaces. First, we found a method to distinguish between slightly rough and rough surfaces using scattering entropy obtained from full-polarization decomposition. Then, we harnessed the co-polarization ratio to mitigate the effect of surface roughness in slightly rough conditions. Later, we developed a soil moisture retrieval model based on the co-polarization ratio, considering incidence angle, residual roughness, and soluble salt content. The validation of the model was verified using field surveying data, yielding an RMSE of 0.026 cm3 ·cm− 3 for the estimated soil moisture. This accuracy is comparable to or surpasses the level achieved by SAR for non-salinized soil moisture retrieval. Our findings showed that Scattering entropy is an effective parameter for distinguishing scattering mechanisms on farmland surfaces effectively. Specifically, when the scattering entropy of farmland is less than 0.5, the co-polarization ratio can mitigate some surface roughness effects. Additionally, when the soil-soluble salt content is incorporated, our model can accurately estimate the soil moisture of salty soil. [ABSTRACT FROM AUTHOR]

The atmospheric activity on Kalimantan Island (KI) is important for regulating regional weather and climate. This study investigates the effect of autumn soil moisture over KI on following winter precipitation over southern China (SC) during 1968–2014. The results show that the autumn soil moisture over the KI has a significant negative correlation with subsequent winter precipitation over SC. The correlation remains statistically significant when using partial correlation to filter out the concurrent influences of El Niño–Southern Oscillation (ENSO) and Indian Ocean Dipole (IOD) signals. The soil moisture anomalies over KI, which initiate in the autumn and persist into the winter, lead to changes in local thermal conditions and atmospheric temperature. Negative soil moisture anomalies over KI will result in positive heating anomalies of the atmosphere above the land surface. This atmospheric heating causes ascending motion, which creates a semi‐closed vertical circulation from KI to the tropical northwest Pacific. This vertical circulation would strengthen the northwest Pacific anticyclone and weaken the East Asian winter monsoon (EAWM). Consequently, southwesterly water vapour flux prevails in the SC as well as the South China Sea (SCS), facilitating the transportation of more water vapour into the SC. Simultaneously, water vapour convergence in the SC. Collectively, these contribute to an addition of precipitation over SC. [ABSTRACT FROM AUTHOR]

The current study dealt with development of nonwoven mulch mat from textile waste and its evaluation in the field for chilli crop. Six needle-punched nonwoven mulches were developed from textile mill waste comprising of cotton, polyester and acrylic in two different ratios. All ratios were varied with three different areal density ratios i.e. 200, 300 and 400 g/m2 with 4-, 3.5- and 3-mm thickness, respectively. The mulch mats were characterised for their physicomechanical properties such as tensile strength, elongation, air permeability, thermal insulation and resistance to sunlight degradation. Further, the developed mulches were analysed for its performance in the field on the hybrid variety of chilli CH-27. Parameters, including soil moisture content, soil temperature, weed suppression, yield and soil degradation were investigated through field tests, against a polyethylene mulch, paddy straw and without mulch. The experimental results revealed that the developed nonwoven mulches worked as buffer media between the atmosphere and soil surface and influenced the temperature of soil. These mulches performed better to maintain the soil temperature than the paddy straw and polyethylene mulch. On the basis of plant grown and crop yield, the best much performance was observed with cotton: polyester: acrylic (70:20:10) with 200 g/m2. [ABSTRACT FROM AUTHOR]

Growth, productivity, and fiber quality of cotton (Gossypium hirsutum L.), a vital fiber-producing cash crop, are severely affected under drought conditions. Seed priming has a proven role in enhancing crop tolerance to abiotic stress, including drought. The objective of this study was to evaluate the effects of seed priming with KNO3 on cotton productivity and fiber quality under drought stress. A germination experiment was established under laboratory conditions with five treatments of seed priming (non-primed or control treatment, hydropriming, and priming with 2.5, 5.0, and 7.5 g KNO3 L−1). Another experiment under polyhouse conditions based on the same seed priming treatments was conducted under three levels of soil water contents (field capacity [FC] 100%: FC100, 75%: FC75, and 50%: FC50). The results obtained showed that there was a clear reduction in the different parameters tested at FC50 in comparison to FC100 (39–54%, 32–44%, 6–12%, and 7–12% reduction for boll number per plant, seed cotton yield, fiber strength, and leaf relative water content, respectively, across all priming treatments). Seed priming with KNO3 at 5 g L−1 effectively alleviated the detrimental effects originated from drought stress and caused 61–73%, 13–16%, and 16–23% increase in seed cotton yield, fiber length, and fiber strength, respectively, across soil moisture levels when compared with the control treatment. The same KNO3 dose caused an increase of 78% in water productivity in comparison to the control plants at FC50. Priming cotton seeds with 5 g KNO3 L−1 holds promise to obtain synchronized germination, enhance fiber quality, and increase yield, especially under water-limited conditions, thereby promoting economic viability and environmental sustainability. Additionally, this practice enhances water productivity, leading to significant water savings and reduced irrigation costs for cotton farmers. This method could be used as potential technology in advancing sustainable agriculture in water-constraint conditions. [ABSTRACT FROM AUTHOR]

Rationale: The development of analytical screening techniques for pesticides is crucial for preventing and mitigating environmental contamination. Mass spectrometry‐based screening methods differ based on the complexity of the sample matrix and the diversity of the target compounds. One of the major challenges is balancing cost reduction in the extraction process with the optimization of analytical results. This protocol introduces a universal and efficient scheme for the qualitative and quantitative schemes for 45 pesticides within a single analytical run. Methods: Water samples were extracted using an SPE column, with the pH adjusted to 7. Soil samples were processed using a modified QuEChERS method. The pretreatment for water samples emphasized selecting appropriate SPE columns and optimizing pH, while for soil samples, the focus was on choosing suitable extraction solvents and extraction salt packages. The enriched samples were then analyzed using liquid chromatography–tandem mass spectrometry (LC–MS/MS). The method was evaluated for accuracy, precision, detection limits, and matrix effects. Results: The method enabled the simultaneous detection of 45 pesticides within a 15‐minute analysis period. SPE recoveries ranged from 56.1% to 118.8%. Instrumental detection limits varied between 0.02 and 1 pg, while method detection limits extended from 0.05 to 18.47 ng/l in soil and water matrices. The approach was successfully applied to water and soil samples, with the pesticide concentration ranging from 0.1 ng/L to 38 μg/L. Conclusions: The protocol substantially enhances the characterization and quantification of 45 pesticides in environmental samples, achieving a remarkable reduction in detection limits by an order of magnitude compared to previous research. This method enables the simultaneous detection of pesticides in both water and soil matrices using a single system, addressing the challenges of using separate systems for different environmental media. Furthermore, this protocol provides a crucial theoretical foundation for managing and safeguarding against pesticide pollution. [ABSTRACT FROM AUTHOR]

Soil moisture plays a significant role in the global hydrological cycle in the field of agriculture, environment science, urban planning and construction, forestry and many more. Soil moisture can be determined using various approaches, however some of the limitations in these approaches are longer time duration, labor intensive, require installation and maintenance, expensive, lower resolution, etc. This research work proposes a soil moisture detection method which is portable, economic and time efficient. Spectroscopic sensor enables rapid soil moisture estimation using photodiodes of varying sensitivities and wavelengths across a broad spectrum of light, allowing precise identification and analysis of various samples based on their unique spectral fingerprints. In this study, a relation between sensor output data and soil moisture percentage value obtained from gravimetric method has been established. Using various regression methods, the highest value of correlation coefficient was found in case of polynomial function of order 3. Residual values of all wavelengths were then calculated by comparing the calculated with the expected moisture values obtained using the polynomial function. Result showed that 705 nanometers (nm) wavelength has the least residual value, thus signifying that the polynomial equation of order 3 at 705 nm wavelength perfectly demonstrates the relation between soil moisture and sensor reading. Furthermore, the results were verified using optimization method which showed that 705 nm wavelength has the highest closeness coefficient, thus verifying this model and observations. This model can be helpful in determining the soil moisture instantaneously instead of hours as seen in traditional gravimetric methods. [ABSTRACT FROM AUTHOR]

The study focused on the photodegradation of profoxydim, a low-toxicity cyclohexanedione herbicide commonly used in rice crops, under simulated sunlight conditions. Profoxydim's behavior in paddy field conditions is not well understood, and this research aimed to fill that gap, particularly examining the effect of commonly utilized organic amendments such as biochar (BC) on its degradation. Results indicated that profoxydim degrades rapidly, with a half-life of 2.4 ± 0.3 h in paddy water and 1.03 ± 0.1 h in paddy soil. However, when BC was introduced, the degradation slowed significantly, extending the half-lives to 3.1 ± 0.2 h in water and 3.07 ± 0.5 h in soil. The study identified five degradation products (DPs) using TOF mass accuracy measurements and MS/MS spectra fragmentation. Two of these DPs were found to be more stable than profoxydim itself. Additionally, the research proposed a novel photodegradation pathway, highlighting processes such as homolytic C-N bond cleavage, photoisomerization, and photoinduced oxidation. The study's findings contribute new insights into the environmental fate of profoxydim, offering a deeper understanding of its transformation in rice paddy fields and aiding in the assessment of potential risks associated with its residues in agricultural environments. [ABSTRACT FROM AUTHOR]

ABSTRACT Increasing drought events coupled with dwindling water reserves threaten global food production and security. This issue is exacerbated by the use of crops that overconsume water, undermining yield. We show here that microorganisms naturally associated with plant roots can undermine efficient water use, whereas modified bacteria can enhance it. We demonstrate that microbe‐encoded genes shape drought tolerance, likely by modulating plant hormonal balance. Specifically, we built a minimal holobiont out of Arabidopsis thaliana and either the bacterium Pseudomonas putida UW4 or its isogenic AcdS− mutant, lacking the enzyme ACC deaminase. This enzyme breaks down the precursor of ethylene, a key regulator in plant response to drought. This single mutation profoundly affected plant physiology and shifted the plant from a ‘water‐spender’ (with more growth under well‐watered conditions) to a ‘water‐spender’ phenotype. Under drought, plants associated with wild‐type bacteria consumed soil water faster, leading to a shorter period of growth followed by death. In contrast, plants associated with the AcdS− mutant managed to maintain growth by reducing water consumption via stomatal closure, thus conserving soil water. This allowed plants to survive severe water deficiency. We conclude that plant‐associated bacteria can modulate plant water use strategies, opening possibilities to engineer water‐savvy crop‐production systems. [ABSTRACT FROM AUTHOR]

Although erosion has naturally been driven by rainfall patterns, human activities have increasingly influenced erosion rates in recent times. However, as climate change alters precipitation, future erosion control may once again depend primarily on climate. The primary goal of this investigation was to ascertain whether the issue of escalated erosion, typically linked to downstream dam effects, could diminish in significance due to projected climatic shifts later in this century. An erosion potential index (Ep), formulated as the ratio of the mass of sediment influx from upstream to the frequency of the sediment-carrying flow events, was computed on a tributary of the Godavari River, located downstream of a dam. Using the Soil & Water Assessment Tool (SWAT), virtual experiments were conducted to distinguish the impacts of the dam from projected climate changes on river geomorphology. Two control scenarios were created using the current climate data and simulated regulated and unregulated states of the basin. Employing climate projections and various mitigation scenarios (SSPs) for the 2060s and 2090s, this study estimated Ep values exclusively under future climatic conditions in an unregulated state of the basin. Results indicate that, in the unregulated state without the existence of the upstream dam, future climate impacts on erosion outweigh the current effects of the dam, underscoring the growing influence of climate on geomorphology. It suggests that existing structural interventions may lose their geomorphic significance in the face of future climate conditions. [ABSTRACT FROM AUTHOR]

Introduction: Breeding programs have developed high-yielding Coffea arabica F1-hybrids as an adaptation against adverse conditions associated with climate change. However, theresponse to drought of coffee F1 hybrids has seldom been assessed. Methods: A trial was established with five C. arabica genotypes (2 pure lines: Catimor and Marsellesa and 3 F1 hybrids: Starmaya, Centroamericano and Mundo Maya) planted under the leguminous tree species Leuceana leucocephala. Coffee growth, yield and physiological responses were assessed under a rain-fed (control: CON) and a rainfall reduction treatment (RR) for 2 years. Results: The RR treatment created a long-term rainfall deficit in a region with suboptimal temperature similar to those predicted by climate change scenarios. Moreover, the RR treatment reduced soil water content by 14% over 2 successive years of production and increased hydric stress of the three F1-hybrids (leaf water potentials averaged -0.8 MPa under RR compared with -0.4 MPa under CON). Under RR, coffee yields were reduced from 16 to 75% compared to CON. Mundo Maya F1 hybrid was the sole high-yielding genotype apable of sustaining its yield under RR conditions. Our results suggested that its significant increase in fine root density (CON = 300 and RR = 910 root.m-2) and its maintenance of photosynthetic rate (2.5 – 3.5 mmol CO2 m-2 s-1) at high evaporative demand might explain why this genotype maintained high yield under RR condition. Discussion: This work highlights a possible drought tolerance mechanism in fruit bearing adult coffee trees where the plant fine root number increases to intake more water in order to preserve turgor and sustainphotosynthesis at high ETo and therefore conserves high yield in dry conditions. [ABSTRACT FROM AUTHOR]

Drought, a prevalent environmental stressor, has had significant consequences on soybean (Glycine max L.), notably impeding its growth and production. Therefore, it is crucial to gain insight into the regulatory responses of soybean plants exposed to drought stress during soybean flowering in the field. In this study, the cultivar 'Liaodou 15' was performed light drought (LD, 24.3% soil moisture content), moderate drought (MD, 20.6% soil moisture content) and severe drought (SD, 16.9% soil moisture content) treatments at flowering stages of soybean and then rehydrated (30% soil moisture content) until harvest. The yield-related indicators were measured and revealed that MD and SD treatments significantly reduced 6.3% and 10.8% of the 100-grain weight. Soybean plants subjected to three drought stresses showed that net photosynthetic rates were 20.8%, 51.5% and 71.8% lower in LD, MD and SD than that of CK. The WUE increased by 31.8%, 31.5% and 18.8% under three drought stress treatments compared to CK. In addition, proline content was 25.94%, 41.01% and 65.43% greater than that of CK under three drought stress treatments. The trend of the MDA content was consistent with that of the proline content. SOD activity was significantly increasing by 10.86%, 46.73% and 14.54% under three drought stress treatments. The activity of CAT in the SD treatment increased by 49.28%. All the indices recovered after rehydration. Furthermore, 54,78 and 51 different expressed metabolomics (DEMs) were identified in the LDCK/LD, MDCK/MD and SDCK/SD groups, respectively. There were 1,211, 1,265 and 1,288 different expressed genes (DEGs) were upregulated and 1,003, 1,819 and 1,747 DEGs were downregulated. Finally, combined transcriptomic and metabolomic analysis suggested that 437 DEGs and 24 DEMs of LDCK/LD group, 741 DEGs and 35 DEMs of MDCK/MD group, 633 DEGs and 23 DEMs of SDCK/SD group, were highly positively correlated in soybean plants under drought stress. Drought stress induced the expression of the PAO1, PAO4, PAO5 and P5CS genes to promote the accumulation of spermidine and proline. Our study elucidates the responses of drought-stressed soybean plants in the field and provides a genetic basis for the breeding of drought-tolerant soybean plants. [ABSTRACT FROM AUTHOR]

Fibrous and pioneer roots are essential in the uptake and transport of water and nutrients from the soil. Their dynamic may be influenced by the changing of soil physicochemical properties due to the addition of biochar, which, in turn, has been shown to improve plant growth and productivity in the short term. However, the long-term effects of biochar application on root dynamics are still widely unknown. In this study, we aimed to investigate the long-term effects of biochar application on grapevine fibrous and pioneer root dynamics and morphological traits in relation to soil characteristics. To this aim, grapevine plants amended in 2009 and 2010 respectively with one and two doses of biochar, were analyzed in their fibrous and pioneer root production and turnover rate, standing biomass, length, and specific root length, over two growing seasons. Our findings demonstrate that in the long term, biochar application significantly increased soil pH, nutrient availability, and water-holding capacity causing a decrease in the production of fibrous and pioneer roots which is reflected in a reduction of the root web characterized though by a higher turnover rate. Furthermore, we observed that these root morpho-dynamical changes were of higher magnitude in the upper soil layers (0-20 cm) and, at least in the long term, with no significant difference between the two doses. These results suggest that in the long term, biochar can be a powerful tool for improving soil quality, which in turn lowers carbon-cost investment toward the root production and maintenance of a reduced root web that might be directed into grapevine growth and productivity. Such effects shed some light on the root plastic and functional adaptation to modified soil conditions facilitated by the long-term application of biochar, which can be used for implementing adaptive agricultural practices to face the current climate change in a frame of sustainable agricultural policies. [ABSTRACT FROM AUTHOR]

Knowledge on the variation of yield and water use efficiency under different mulching methods is important for guiding rained maize production in the Loess Plateau area. In this study, eight different plastic film mulching methods was established to analyze the maize growth, soil water content and soil temperature changes of dryland maize, and increase yield and water use efficiency (WUE). The field experiment was conducted in 2019, and eight treatments were set up, including a traditional flat planting without mulching (CK), ridge-furrow with ridges mulching black plastic film and furrows mulching straw (HJ), ridge-furrow with ridges mulching black plastic film and furrows bare (HL), ridge-furrow with ridges mulching liquid plastic film and furrows mulching straw (YJ), ridge-furrow with ridges mulching liquid plastic film and furrows bare (YL), ridge-furrow with ridges mulching biodegradable plastic film and furrows mulching straw (SJ), ridge-furrow with ridges mulching biodegradable plastic film and furrows bare (SL) and ridge-furrow with ridges bare and furrows mulching straw (NJ). Furthermore, the AHP-TOPSIS was employed to evaluate the optimal mulching method for maize. The results showed that compared with CK and NJ treatment, the soil water content and soil storage were significantly changes with other treatments in the reproductive period of maize. Among the six mulching methods, maize yield in HJ, HL, YJ, YL, SJ, and SL treatments were 46.28%, 61.95%, 70.30%, 51.02%, 52.02% and 53.53% significantly greater than CK treatment. In addition, dryland maize WUE was 66.53% and 84.01% higher in the YJ and YL treatments with ridges mulching liquid plastic film than in the CK treatment, respectively. The optimal treatments of economic benefits were YL and HJ. Through AHP-TOPSIS comprehensive analysis, the optimal mulching methods were YL and HJ treatment. Current field trials indicate that YL treatment could serve as a promising option to improve dryland maize yield, WUE, and reducing environmental risks in the Loess Plateau of China. [ABSTRACT FROM AUTHOR]

ABSTRACT It has been broadly reported that future climate change will most likely affect the spatio‐temporal distribution of water resources and consequently droughts. There is a prevailing notion that an increase in temperature and frequency of heat waves are expected to result in more intense droughts in the coming years. In this study, we aimed to evaluate the effect of the potential evapotranspiration (PET) method selection on future drought projections over Poland. In our study, simulations of the Soil and Water Assessment Tool (SWAT) model were conducted, utilising an ensemble of six EURO‐CORDEX projections, spanning the period from 2006 to 2100 under the RCP8.5 scenario. Two model setups with two different PET methods (Penman‐Monteith—PM and Hargreaves—HAR) were used. For drought conditions evaluation we selected the Standardized Precipitation Index (SPI) and Standardized Precipitation‐Evapotranspiration Index (SPEI) for meteorological drought, Standardized Streamflow Index (SSI) for hydrological drought, and Standardized Soil Moisture Index (SMI) for agricultural drought. The meteorological and hydrological droughts were calculated using a 12‐month time aggregation window, while agricultural drought was calculated using a 3‐month window. Climate projections revealed that by 2080s annual mean temperature and precipitation increase is expected by up to +3.4°C and +10.3% respectively. Under future climate conditions duration and severity of meteorological droughts are projected to decrease. PM method leads to a higher PET increases (1.35 mm year−1) than the HAR method (1.1 mm year−1) throughout the century which entail diverging signal of change for agricultural and hydrological droughts. PM‐ and HAR‐based simulations indicate increase in the total duration and cumulative severity of agricultural droughts, buthowever, for HAR‐based projections, the increase is much less. For hydrological droughts the signal of change is similar for both PET methods, but considerably distinct in magnitude. Considering the entire simulation period, by the end of the century cumulative severity of hydrological droughts is projected to decrease, with a much more pronounced decline for HAR (70% reduction) than for the PM method (35% reduction). Our study demonstrated that methodological choices are crucial to the assessment of future drought risk under climate change. [ABSTRACT FROM AUTHOR]

Associative N2 fixation (ANF) is widespread but poorly characterized, limiting our ability to estimate global inputs from N2 fixation. In some places, ANF rates are at or below detection most of the time but occasionally and unpredictably spiking to very high rates. Here we test the hypothesis that plant phenology and rainfall events stimulate ANF episodes. We measured ANF in intact soil cores in switchgrass (Panicum virgatum L.) in Michigan, USA. We used rain exclusion shelters to impose three rainfall treatments with each receiving 60 mm of water over a 20-day period but at different frequencies. We concurrently established a treatment that received ambient rainfall, and all four treatments were replicated four times. To assess the effects of plant phenology, we measured ANF at key phenological stages in the ambient treatment. To assess the effects of rainfall, we measured ANF immediately before and immediately after each wetting event in each treatment involving rainfall manipulation. We found that the previous day's rainfall could explain 29% of the variation in ANF rates within the ambient treatment alone, and that bulk soil C:N ratio was also positively correlated with ANF, explaining 18% of the variation alone. Wetting events increased ANF and the magnitude of response to wetting increased with the amount of water added and decreased with the amount of inorganic N added in water. ANF episodes thus appear to be driven primarily by wetting events. Wetting events likely increase C availability, promote microbial growth, and make rhizosphere conditions conducive to ANF. [ABSTRACT FROM AUTHOR]

Sowing depth is a critical factor in crop growth and is determined by both the soil conditions and the force of the opener. The trend for the future is to control sowing depth based on soil dynamic parameters. Therefore, this paper developed a downforce measurement and control system based on the 'T'-shaped furrow opener and investigated the influence of soil dynamic parameters and opener downforce on sowing depth. A test-rig was constructed and the accuracy of the system in measuring downforce and controlling downforce and sowing depth was verified. The study shows that at different sowing depths, soil moisture, bulk density and their interaction have a significant effect on downforce (P < 0.01). As the moisture content decreases and the bulk density increases, the required downforce increases for the same sowing depth. A mathematical model of downforce-sowing depth-soil bulk density-soil moisture content was established using experimental data, with an R2 of 0.916, VIF <5 and a Durbin-Watson value of 1.628. Field experiments show that, at an operating speed of 6 km h−1, the control strategy based on the soil dynamic parameters predicted by downforce theory significantly outperformed the strategy of adjusting the downforce in response to perceived changes in downforce. This indicates that after dynamic and rapid measurement of soil bulk density and moisture content during field operations, sowing depth can be accurately controlled based on the directed downforce of the opener. The mathematical model provides a theoretical basis for sowing depth control based on soil dynamic parameters. • Proposing a sowing depth control strategy based on soil dynamic parameters. • System developed under static conditions and validated through dynamic experiments. • A mathematical model for the precise control of sowing depth was established. [ABSTRACT FROM AUTHOR]

With global climate change, linking vegetation phenology with net ecosystem productivity (NEP) is crucial for assessing vegetation carbon storage capacity and predicting terrestrial ecosystem changes. However, there have been few studies investigating the relationship between vegetation phenology and NEP in the middle and high latitudes of the Northern Hemisphere. This study comprehensively analyzed vegetation phenological changes and their climate drivers using satellite data. It also investigated the spatial distribution and climate drivers of NEP and further analyzed the sensitivity of NEP to vegetation phenology. The results indicated that the average land surface phenology (LSP) was dominated by a monotonic trend in the study area. LSP derived from different satellite products and retrieval methods exhibited relatively consistent responses to climate. The average SOS and POS for different retrieval methods showed a higher negative correlation with nighttime temperatures compared to daytime temperatures. The average EOS exhibited a higher negative correlation with daytime temperatures than a positive correlation. The correlations between VPD and the average SOS, POS, and EOS showed that the proportion of negative correlations was higher than that of positive correlations. The average annual NEP ranged from 0 to 1000 gC·m−2. The cumulative trends of NEP were mainly monotonically increasing, accounting for 61.04%, followed by monotonically decreasing trends, which accounted for 17.95%. In high-latitude regions, the proportion of positive correlation between VPD and NEP was predominant, while the proportion of negative correlation was predominant in middle-latitude regions. The positive and negative correlations between soil moisture and NEP (48.08% vs. 51.92%) were basically consistent in the study area. The correlation between SOS and POS with NEP was predominantly negative. The correlation between EOS and NEP was overall characterized by a greater proportion of negative correlations than positive correlations. The correlation between LOS and NEP exhibited a positive relationship in most areas. The sensitivity of NEP to vegetation phenological parameters (SOS, POS, and EOS) was negative, while the sensitivity of NEP to LOS was positive (0.75 gC·m−2/d for EVI vs. 0.63 gC·m−2/d for LAI vs. 0.30 gC·m−2/d for SIF). This study provides new insights and a theoretical basis for exploring the relationship between vegetation phenology and NEP under global climate change. [ABSTRACT FROM AUTHOR]

Hyperbolae in radargrams are caused by a variety of small subsurface objects. The analysis of their curvature enables the determination of propagation velocity in the subsurface, which is important for exact time-to-depth conversion and migration and also yields information on the water content of the soil. Using deep learning methods and fitting (DLF) algorithms, it is possible to automatically detect and analyze large numbers of hyperbola in 3D Ground-Penetrating Radar (GPR) datasets. As a result, a 3D velocity model can be established. Combining the hyperbola locations and the 3D velocity model with reflection depth sections and timeslices leads to improved archaeological interpretation due to (1) correct time-to-depth conversion through migration with the 3D velocity model, (2) creation of depthslices following the topography, (3) evaluation of the spatial distribution of hyperbolae, and (4) derivation of a 3D water content model of the site. In an exemplary study, we applied DLF to a 3D GPR dataset from the multi-phased (2nd to 12th century CE) archaeological site of Goting on the island of Föhr, Northern Germany. Using RetinaNet, we detected 38,490 hyperbolae in an area of 1.76 ha and created a 3D velocity model. The velocities ranged from approximately 0.12 m/ns at the surface to 0.07 m/ns at approx. 3 m depth in the vertical direction; in the lateral direction, the maximum velocity variation was ±0.048 m/ns. The 2D-migrated radargrams and subsequently created depthslices revealed the remains of a longhouse, which was not known beforehand and had not been visible in the unmigrated timeslices. We found hyperbola apex points aligned along linear strong reflections. They can be interpreted as stones contained in ditch fills. The hyperbola points help to differentiate between ditches and processing artifacts that have a similar appearance as the ditches in time-/depthslices. From the derived 3D water content model, we could identify the thickness of the archaeologically relevant layer across the whole site. The layer contains a lot of humus and has a high water retention capability, leading to a higher water content compared to the underlying glacial moraine sand, which is well-drained. [ABSTRACT FROM AUTHOR]

In order to anticipate residual errors and improve accuracy while reducing uncertainties, this work integrates the long short-term memory (LSTM) with the Soil and Water Assessment Tool (SWAT) to create a deep learning (DL) model that is guided by physics. By forecasting the residual errors of the SWAT model, the SWAT-informed LSTM model (LSTM-SWAT) differs from typical LSTM approaches that predict the streamflow directly. Through numerical tests, the performance of the LSTM-SWAT was evaluated with both LSTM-only and SWAT-only models in the Upper Heihe River Basin. The outcomes showed that the LSTM-SWAT performed better than the other models, showing higher accuracy and a lower mean absolute error (MAE = 3.13 m3/s). Sensitivity experiments further showed how the quality of the training dataset affects the performance of the LSTM-SWAT. The results of this study demonstrate how the LSTM-SWAT may improve streamflow prediction greatly by remote sensing and in situ observations. Additionally, this study emphasizes the need for detailed consideration of specific sources of uncertainty to further improve the predictive capabilities of the hybrid model. [ABSTRACT FROM AUTHOR]

Accurate high-resolution soil moisture maps are crucial for a better understanding of hydrological processes and energy cycles. Mapping strategies such as downscaling and interpolation have been developed to obtain high-resolution soil moisture maps from multi-source inputs. However, research on the optimization performance of integrating downscaling and interpolation, especially through the use of mutual covariates, remains unclear. In this study, we compared four methods—two standalone methods based on downscaling and interpolation strategies and two combined methods that utilize soil moisture maps as mutual covariates within each strategy—in a case study of daily soil moisture mapping at a 1 km resolution in the Tibetan Plateau. We assessed mapping performance in terms of prediction accuracy and differences in spatial coverage. The results indicated that introducing interpolated soil moisture maps into the downscaling strategy significantly improved prediction accuracy (RMSE: −5.94%, correlation coefficient: +14.02%) but was limited to localized spatial coverage (6.9% of grid cells) near in situ sites. Conversely, integrating downscaled soil moisture maps into the interpolation strategy resulted in only modest gains in prediction accuracy (RMSE: −1.07%, correlation coefficient: +1.04%), yet facilitated broader spatial coverage (40.4% of grid cells). This study highlights the critical differences between downscaling and interpolation strategies in terms of accuracy improvement and spatial coverage, providing a reference for optimizing soil moisture mapping over large areas. [ABSTRACT FROM AUTHOR]

Information on water absorption from the air by urea fertilizers and on NH3 loss when applied to grasslands is limited. Urea application to grassland is typically broadcast (Bcast), whereas urea‐ammonium nitrate (UAN) is applied either Bcast or in bands (dribble). This work was conducted to (1) evaluate water absorption from the air by Bcast granular urea, Bcast UAN, and dribble UAN under laboratory conditions, and (2) compare NH3 losses from Bcast urea, Bcast UAN, and dribble UAN when applied to a grassland. Six field studies were conducted from 2017 to 2019. In the laboratory, Bcast UAN exposed to 100% relative humidity absorbed water from air at a faster rate than dribble UAN and Bcast urea. In the field, all three fertilizers lost similar amounts of NH3 when applied to relatively wet soil (> −0.1 MPa). In contrast, when the fertilizers were applied to dry soil (≤ −1.2 MPa), Bcast UAN lost the most NH3 (17.3% and 19.8%) likely because of its capacity to absorb water from the air. Also, at −1.2 MPa, dribble UAN lost more NH3 than Bcast urea (15.3 vs. 10.7%, p < 0.05), probably because the low osmotic potential of UAN (−55 MPa) allowed it to absorb water from the soil at a faster rate than urea could absorb water from the air. In contrast, when the soil water potential was −5.7 MPa, dribble UAN lost less NH3 than Bcast urea (4.4 vs. 17.3%, p < 0.05), likely because the low soil water potential reduced its water absorption. Core Ideas: Water absorption from air was faster for broadcast (Bcast) urea‐ammonium nitrate (UAN) than from banded UAN or granular urea.Urea concentration in solution decreased faster below 6 mol L−1 in Bcast and banded UAN than in granular urea.Bcast UAN lost more NH3 than banded UAN or granular urea when soil water content was low (< −1.2 MPa).UAN (Bcast or banded) and granular urea lost similar amounts of ammonia when soil water content was high (> −0.1 MPa). Plain Language Summary: Granular urea or nitrogen solutions containing urea can be broadcast (Bcast) or applied in bands to grasslands, where they absorb water from the air or from the soil to release nitrogen to the forage. In grasslands, a significant portion of the applied fertilizer falls on leaves and therefore absorbs water from the air. This work was conducted to evaluate absorption of water from the air for Bcast and banded nitrogen solution and from Bcast granular urea. Bcast nitrogen solution absorbed water from the air at a faster rate than banded nitrogen solution or granular urea. This study also evaluated gaseous losses of ammonia from Bcast and banded nitrogen solution and from Bcast granular urea when applied to a grassland. Ammonia losses were similar for all three fertilizers when the soil water content was high, but when the water content was low, Bcast nitrogen solution lost more ammonia than banded nitrogen solution or Bcast granular urea. [ABSTRACT FROM AUTHOR]

The TEROS 10 and TEROS 12 are widely used capacitance‐based sensors for measuring volumetric water content (θv${{\theta }_v}$), but few systematic studies of the measurement volume and accuracy of these sensors have been published. The objectives of this study were to (1) calibrate and validate these sensors in mineral soils, (2) determine the sensing volume of each sensor, and (3) evaluate the temperature sensitivity of the sensors. Both sensors were calibrated in the laboratory using columns of packed soil at multiple moisture levels from air‐dry to near saturation. Sensors were validated using additional laboratory and field measurements. The sensing volume was determined by quantifying the response of raw sensor outputs while increasing the level of oven‐dry sand, moist sand (0.100 cm3 cm−3), or water around the sensor in the radial and axial directions. Temperature sensitivity was tested in controlled conditions over a range of temperatures from 2°C to 40°C using encapsulated sensors in packed soil columns at constant θv${{\theta }_{v}}$. Linear calibration models resulted in mean absolute error ≤0.030 cm3 cm−3 for both sensors during laboratory and field validations. In moist sand, the sensing volume contributing 95% of the maximum sensor response was 439 cm3 for the TEROS 10 and 423 cm3 for the TEROS 12. Both sensors exhibited changes in θv${{\theta }_v}$ of ≤0.02 cm3 cm−3 when subjected to a temperature change from 2°C to 40°C. For the soils considered here, both sensors demonstrated accuracy that is likely sufficient for a variety of agricultural and hydrological applications. Core Ideas: A linear calibration equation provided mean absolute error (MAE) ≤0.030 cm3 cm−3 for both the TEROS 10 and TEROS 12 sensors.TEROS 10 sensing volume in moist sand ranged from 439 to 1741 cm3 depending on the stopping criterion.TEROS 12 sensing volume in moist sand ranged from 423 to 1825 cm3 depending on the stopping criterion.TEROS 10 and TEROS 12 sensors had small (≤0.02 cm3 cm−3) changes in water content due to soil thermal oscillations. [ABSTRACT FROM AUTHOR]

Understanding the effects of abandoned coal mine ecological restoration on soil quality and function is important to protect the regional ecological environment. This study aims to evaluate the ecological restoration effects of soil quality in abandoned coal mine area. Taking Fengcheng County, a typical coal‐rich area in southern China, as a case, this study took 120 soil samples to investigate the influence of restoration years on soil quality by using an integrated soil quality index (SQI). Results indicated that restoration years had significant effects on the saturated hydraulic conductivity (Ks) by affecting the soil bulk density, clay content, and soil water content. Furthermore, clay, soil organic matter, Ks, and pH were selected to assess the effect of ecological restoration years on soil quality. It was found that the ecological restoration 8 years (ER8) site had higher SQI value, indicating ecological restoration years showed a positive correlation with SQI in abandoned coal mine area. Since there was a 4‐year gap between ecological restoration 4 years site and ER8 site, the ecological restoration may be effective between 5 and 8 years. The results of this study are of great significance for improving the effects of ecological restoration and management in abandoned coal mine area. Core Ideas: Soil quality index (SQI) of different ecological restoration years was valued, and ecological restoration in the abandoned coal mine was helpful to improve soil quality.Soil organic matter (SOM), clay content, saturated hydraulic conductivity (Ks), and pH were representative indicators for calculating soil quality index (SQI).SQI was significantly improved with the increase of ecological restoration years.SQI was an effective tool to assess the ecological restoration management practices. Plain Language Summary: Many coal mines close as they reach the end of their viability or in response to policy, which results in the increase of abandoned coal mines. Understanding the effects of abandoned coal mine ecological restoration on soil nutrient condition is vital for environmental protection. In this study, an integrated soil quality index (SQI) was used to evaluate the effect of restoration years on soil quality. Clay, soil organic matter, saturated hydraulic conductivity (Ks), and pH were representative indicators for calculating SQI. SQI was significantly improved with ecological restoration years in abandoned coal mine area. The results of this study are of great significance for improving the effects of ecological restoration and management in abandoned coal mine area. [ABSTRACT FROM AUTHOR]

Soil shrinkage characteristic curves are used to describe the shrinkage behavior and hydraulic properties of unsaturated soils. To construct soil shrinkage characteristic curves, a high‐data‐density measurement method is needed that relates water content to soil volume changes. We present a fully automated soil shrinkage measurement setup, based on the simplified evaporation method, to characterize the shrinkage behavior of undisturbed natural expansive clay soils. The high data density creates the opportunity to produce soil shrinkage characteristic curves without the need for a mathematical model. The technique allows for resaturation of the samples after drying, enabling differentiation between reversible and irreversible shrinkage. The setup consists of the commercialized HYPROP2 apparatus combined with optical distance sensors to measure the horizontal and vertical dimensions of the samples, yielding data on the sample volume, weight, and soil water suction. The measurement frequency is once per 10 min, and the measurement period is up to 4 weeks, providing a detailed time series of the drying and shrinkage characteristics. The setup can capture the different shrinkage phases and offers the opportunity to relate the soil shrinkage characteristic curve to soil water suction. The measurement data acquisition rate and accuracy enable detailed interpretation of soil water retention curves for nonrigid soils and are shown to be essential for understanding and quantifying the shrinkage potential of several types of deposits. Core Ideas: We present a new fully automated setup to accurately measure soil shrinkage curves of expansive soils.The method enables the construction of soil shrinkage curves without applying a mathematical model.Establishing soil water retention curves can be improved by simultaneously measuring shrinkage during drying. Plain Language Summary: Soil shrinkage is the decrease of soil volume due to lower water levels, which can damage infrastructure, cause land subsidence, and alter soil properties. To predict soil shrinkage accurately, it should be monitored either in the field or on natural samples in the lab, requiring high data density. We developed and tested a method to capture the shrinkage behavior of natural soil samples. Our results show that this method allows us to describe shrinkage without relying on mathematical models and also study the effects of soil wetting. This study enhances our ability to measure and understand soil shrinkage, which is crucial for predicting soil behavior in various environmental and engineering scenarios. [ABSTRACT FROM AUTHOR]

The two most important abiotic plant stressors that impact plant development and crop yields are water stress and salinity stress. These issues are particularly important in arid and semi‐arid regions. According to a 2019 research paper, "thirty crop species provide 90% of our food, most of which display severe yield losses under moderate salinity." Moderate salinity is defined as extracted pore‐water salinity in the range of 4–8 dS m−1. Currently, commercially available soil moisture and bulk soil electrical conductivity sensors can estimate in situ soil pore‐water electrical conductivity with suitably calibrated soil moisture and electrical conductivity models for a wide range of soil types and growing media. With knowledge of the pore‐water electrical conductivity it is possible to estimate osmotic tension. Furthermore, there are commercially available dielectric tensiometers that provide soil water tension measurements from the water content of a porous matrix component that is in equilibrium with the water capillary forces in the surrounding soil or growing media. Combining soil moisture and soil water tension measurements enables water retention curves and the hydraulic properties of a soil to be determined. However, the overall ability of a plant to extract water from a soil or substrate is typically dominated by water tension and osmotic tension. Currently, while the technology blocks exist in different commercial offerings, the combination of a water tension and osmotic tension in an integrated sensor does not exist. A key benefit of the porous matrix in a dielectric tensiometer is that electrical measurements include a component of extracted water from the soil or growing media. With the appropriate dielectric characterization of the porous matrix, there should be no need for soil‐specific calibrations. The aim of the paper is to outline the measurement processing that could be implemented into an integrated water tension and osmotic tension sensor. Core Ideas: An integrated water tension and osmotic tension sensor does not exist.A dielectric tensiometer performs electrical measurements on extracted water from the soil.Characterization of the porous matrix avoids soil‐specific calibrations for osmotic tension. [ABSTRACT FROM AUTHOR]

The volumetric and hydrological responses of clayey soils subjected to drying-wetting (D-W) cycles are of paramount importance for the integrity of geoenvironmental infrastructures. The study aimed to investigate the cracking behavior of clayey soils under D-W cycles by using advanced 2D imaging and 3D scanning techniques to capture the initiation and propagation of desiccation cracks within a soil specimen. The temporal variation in the soil water content and the corresponding 2D digital photography and 3D morphology of cracks were simultaneously monitored, and the cracking characteristics were interpreted. It was found that the time-dependent evaporation process was independent of the D-W cycles. Both 2D and 3D characterization showed the cracking hysteresis phenomenon in the unsaturated soil, which indicates the dependency of the crack opening and closure on the degree of saturation. D-W cycles led to the formation of subcracks and the increase in the total crack length, reflecting the soil degradation. Additionally, it was demonstrated that the 3D characterization exhibited the advantage of capturing the volumetric change and the subtle change in the macroporosity of the cracked soil over the 2D visualization. The current study provides a perspective of combining 2D and 3D characterization for interpreting the volumetric change of cracked soils and enhancing the understanding of the hydromechanical responses and the soil-atmosphere interactions. [ABSTRACT FROM AUTHOR]

The pressure infiltration of fresh and salty bentonite slurries against a medium-fine sand has been investigated in a laboratory setup. In the tests, two series of salty bentonite slurries were used: non-pre-hydrated salty slurry, for exploring what will happen if directly salty water is used to make bentonite slurry, and pre-hydrated salty slurry, for identifying the consequence of pre-hydrated fresh bentonite slurry mixing with the salty water in the soil pores. The salty water employed was a mixture of different percentages of freshwater and seawater. Experimental results show that the test with non-pre-hydrated salty slurry exhibited a significantly faster and shorter (time) mud spurt, or even no mud spurt at all, compared to the test with fresh or pre-hydrated salty slurry. The influence of salty water on the pre-hydrated fresh bentonite is less than on the non-pre-hydrated slurry and depends on the seawater content in the salty water. Compared with the test with fresh bentonite slurry, a slower and shorter (time) mud spurt could be seen in the test with the pre-hydrated salty slurry when the seawater content was not more than 20%. As seawater content exceeded 20%, a faster mud spurt showed up; however, the timespan of the mud spurt may be shorter or longer, mainly depending on the viscosity and sedimentation behavior of the bentonite. A model to estimate the slurry infiltration distance during mud spurt is introduced, which agrees well with the experimental results using the measured input parameters. After the mud spurt, a filter cake would form in each test. The permeability of the filter cake increased with the increase in seawater content. Directly mixing salty water remarkably increased the permeability of the filter cake, while the pre-hydration of bentonite could reduce this increase. For instance, with the salty water containing 10% seawater, the permeabilities of the filter cakes formed by fresh bentonite slurry, non-pre-hydrated salty slurry, and pre-hydrated salty slurry with the 50 g/L bentonite concentration were 1.69 × 10−9 m/s, 2.26 × 10−8 m/s, and 3.23 × 10−9 m/s, respectively. [ABSTRACT FROM AUTHOR]

The dynamic effects in soil water retention curves (SWRCs) have been the focus of much research. However, most studies implemented short column tests in a few centimeters, under which a semi-permeable porous media inevitably minimizes or magnifies the dynamic effects. In this study, full-scale sand column tests were conducted to eliminate this flaw by preparing a saturated zone under the unsaturated one. The soil suction and moisture profiles were monitored using high-precision tensiometers and spatial time-domain reflectometry, thereby providing a rational overshooting range of the dynamic SWRC. The results confirm that the dynamic primary drainage curve overshoots the static one. The dynamic effects were estimated quantitatively from the soil moisture re-equilibrium time (τS) and dynamic coefficient (τp), falling within reasonable ranges from previous studies. The τp increases log-linearly with decreasing moisture content and can be estimated well from the corresponding τS and the first derivative of SWRC. Also, the τp increases as the soil becomes finer and better graded, which agrees with more-prominent dynamic effects for lower-permeability reservoirs from petroleum studies but disagrees with more-significant dynamic effects for higher-permeability sand from soil-hydrology studies. The analysis shows that the dynamic effects are not dominated solely by the τp or permeability but also by the groundwater dynamics, which can be seen as a pressure boundary from the saturated zone. This finding explains the significant dynamic effects for both high- and ultra-low-permeability geomaterial. Therefore, the present full-scale soil column setup with a prepared saturated zone is recommended for academic investigations of dynamic SWRCs. [ABSTRACT FROM AUTHOR]

This paper presents a study of the hydraulic response of an infinite unsaturated slope exposed to a perturbation of the ordinary seasonal climatic cycle. The ground flow is modelled via a simplified one-dimensional finite difference scheme by decomposing the two-dimensional slope seepage into antisymmetric and symmetric parts. The numerical scheme incorporates two distinct hysteretic and non-hysteretic soil water retention laws, whose parameters have been selected after a preliminary sensitivity analysis. Results indicate that, in the hysteretic case, the "memory" of the perturbation takes a long time to fade, and the ordinary soil saturation cycle is only restored after several years of normal weather. Instead, in the non-hysteretic case, the recovery of the ordinary saturation regime is almost immediate after the perturbation. In contrast with the markedly different predictions of degree of saturation, both hysteretic and non-hysteretic slope models predict virtually identical evolutions of negative pore water pressures, with an almost immediate restoration of the ordinary cycle after the perturbation. [ABSTRACT FROM AUTHOR]

The soil–water characteristic curve (SWCC) is the most fundamental relationship in unsaturated soil mechanics, relating the amount of water in the soil to the corresponding matric suction. From experimental evidence, it is known that SWCC exhibits hysteresis (i.e., wetting/drying path dependence). Various factors have been proposed as contributors to SWCC hysteresis, including air entrapment, contact angle hysteresis, ink-bottle effect, and change of soil fabric due to swelling and shrinkage; however, the significance of their contribution is debated. From our pore-scale numerical simulations, using the multiphase lattice Boltzmann method, we see that, even when controlling for all these factors, SWCC hysteresis still occurs, indicating that there is some underlying source that is not accounted for in these factors. We find this underlying source by comparing the liquid/gas phase distributions for simulated wetting and drying experiments of 2D and 3D granular packings. We see that during wetting (i.e., pore filling) many liquid bridges expand simultaneously and join together to fill the pores from the smallest to the largest, allowing menisci with larger radii of curvature (lower matric suction). Whereas, during drying (i.e., pore emptying), only the limited existing gas clusters can expand, which become constrained by the size of the pore openings surrounding them and result in menisci with smaller radii of curvature (higher matric suction). [ABSTRACT FROM AUTHOR]

The contributions of windthrows and coarse woody debris (deadwood) to soil organic matter dynamics are controversial and poorly studied. Windthrows are a natural disturbance, the frequency of which is predicted to increase because of global climate change. This paper assesses the impact of a mass windthrow, namely, deadwood and gaps in the forest canopy, on the total C and N contents and stocks, as well as on the microbial activity of the soils developed from cover loesslike loam in a multispecies mesophytic broadleaved forest. The soil, which is a combination of soddy podzolic and gray soils (Retisols and Luvisols according to the WRB classification) was studied in a mass windthrow area 15 years after the catastrophic event. Soil was sampled from the top 5-cm layer of the A horizon in three biotopes: (1) under a fallen trunk; (2) 50–70 cm from the trunk in a deadwood-free area; and (3) in the background forest surrounding the windthrow site. A series of one-way ANOVAs and the pairwise Games–Howell test were used to assess the effects of tree species and three types of biotopes on the C and N contents and stocks, C/N ratio, microbial characteristics, pH, soil moisture content, and soil bulk density. The contents and stocks of C and N, soil microbial activity, and moisture were the highest in the mass windthrow area free of fallen trunks. The estimates for the soils under fallen trunks were mostly similar to those of the background forest. Our study shows that the gaps in forest canopy and coarse woody debris following a mass windthrow have significant effects on the characteristics of loamy soil. [ABSTRACT FROM AUTHOR]

Black huckleberry (Vaccinium membranaceum)—an economically, ecologically, and culturally important shrub across the Pacific and Inland Northwest—is experiencing widespread declines in suitable habitat because of fire suppression and climate change. We tested the role of experimentally placed downed woody debris (DWD) in mitigating unsuitable habitat conditions through creating favorable abiotic microsites and promoting black huckleberry seedling survival. We planted 1‐year‐old black huckleberry seedlings at four distances (0, 0.25, 0.5, and 1.5 m) from DWD, on the north and south aspects of east‐to‐west‐oriented DWD, at three study sites in Northern Idaho, United States. Over one growing season (May to September), we measured seedling survival, chlorophyll fluorescence (Fv/fm), soil surface temperature (SST), and soil volumetric water content (VWC) monthly. Only 21% of seedlings survived the entire season, but survival on the north DWD aspect (28.3%) was twice that of the south (14.2%). Additionally, survival at the nearest distances (0 and 0.25 m; 29%) was double that of farther distances (0.5 and 1.5 m; 13.6%) for both DWD aspects. The north aspect and nearest distances were also associated with the highest Fv/fm, lowest SST, and highest VWC, confirming expected abiotic characteristics of the DWD‐associated microsite. The distinct spatial and directional effects highlight a facet of DWD microsites, which can improve best practices for microsites during restoration. We demonstrate that DWD‐facilitated microsites can be a pivotal restoration tool to ameliorate climate extremes and enhance shrub recruitment into more durable life stages. [ABSTRACT FROM AUTHOR]

Widespread floods affecting multiple subbasins in a river basin have implications for infrastructure, agriculture, environment, and groundwater recharge. However, the crucial linkage between widespread floods and their drivers remains unexplored for Indian subcontinental river basins. Here, we examine the occurrence and drivers of widespread flooding in seven Indian subcontinental river basins during the observed climate (1959–2020). The peninsular river basins have a high probability of widespread flooding, compared to the transboundary basins of the Ganga and Brahmaputra. Favorable antecedent baseflow and soil moisture conditions, uniform precipitation distribution, and precipitation seasonality determine the probability of widespread floods in Indian river basins. The widespread floods are associated with large atmospheric circulations that cause precipitation in a large part of a river basin. Our findings highlight the prominent drivers and mechanisms of widespread floods with implications for flood mitigation in India. [ABSTRACT FROM AUTHOR]

The objective of this study is to develop a methodological approach to assess ecosystem functioning in terms of carbon uptake and sequestration. To achieve this, a model was developed to forecast Net Primary Productivity (NPP) and tested in a rural area, the Thrace region (NE Greece). Monthly net photosynthesis data from July 2015 to February 2024 was estimated using the MODerate Resolution Imaging Spectroradiometer (MODIS) Aqua MYD17A2H v061 dataset for the study area. This dataset was used as the dependent variable in an Autoregressive Integrated Moving Average (ARIMA) model. The predictive ability of monthly Land Cover (LC) and Soil Moisture (SM) data at various time lags was examined, and variables found to be significant predictors were introduced into the model as external predictors. The study found that crop areas and SM conditions exert the greatest influence on NPP, with areas containing trees exerting a lesser impact. Additionally, NPP was estimated for seven different LC and SM scenarios from March 2023 to February 2024. [ABSTRACT FROM AUTHOR]

The soil moisture (SM) balance is affected by afforestation. In this study, the CiteSpace software was used to review the literature on the impact of afforestation on SM, and we further present research findings on the Loess Plateau (LP) as follows: (1) the spatio-temporal heterogeneity of SM varies depending on the research scale; (2) the presence of a dried soil layer significantly hinders deep SM recharge; (3) the accumulation of net primary productivity (NPP) may be occurring at the expense of SM. The following research topics are discussed: (1) the recharge and consumption of deep SM in LP; (2) the green water footprint and its shortage of non-crop greenery for evaluating SM allocation and use; (3) the development of inclusive models encompassing different spatial scales to assess the limits of soil water carrying capacity for vegetation (SWCCV). [ABSTRACT FROM AUTHOR]

To separate the contributions of climate change and human activities to alterations in flow for the Ahar Chay watershed in Iran, change points of the normalized difference vegetation index (NDVI) and evapotranspiration (ET) were distinguished before and after significant alterations. The Budyko model and Soil and Water Assessment Tool (SWAT) were used to find the reduction in runoff. New Penman-Monteith-Leuning (PML) ET data was used to consider plant types. Results revealed an increase in NDVI coinciding with the change point in 1998, as well as ET in 1999. The significance of the Sattarkhan Dam became evident when distinguishing the impacts upstream versus downstream of the dam. Results also indicated that climate change contributed significantly to upstream flow reduction (83.5%), whereas downstream reductions were primarily linked to human-related impacts (59.7–82.5%). Assuming no dam interception, 2007 became the change point, signifying a 37.5% reduction in average flow from before to after this point due to the increased vegetation cover. [ABSTRACT FROM AUTHOR]

Uranium is a highly hazardous heavy metal and radionuclide. The distribution of uranium in rock, soil, fruit, and water has been measured in the Balod area. Samples were collected using one square kilometer griding technique from Jhalmala Paragaon, Parsoda, Dewerbatt, Pakurbatt, and Jagarata Deur tarai. The distribution of uranium is quantified within the ranges of 0.7–3.6 (ppb) in soil, 0.5–4.4 ppb in rock, 0.2–52.6 ppb in groundwater, and 0.2–0.7 ppb in fruit.The presence and movement of uranium has been verified through a systematic statistical investigation, and its mobility in environmental components has been established. [ABSTRACT FROM AUTHOR]

Radioactive elements have coexisted in our environment and the health risks assessment for humans associated with the presence of these radioactive elements in the environment is necessary. This study was conducted in the Mansa district of Punjab for estimating the health risks to the people living in the region. 22 Soil and water samples from collected from various locations in the district. The range of Ra, Th and K in the soil samples varied from 28.09 Bq/kg to 55.91 Bq/kg, from 23.32 Bq/kg to 79.64 Bq/kg and from 189.22 Bq/kg to 425.58 Bq/kg, respectively. Doses to different organs have been calculated and ultimately Expected lifetime cancer risk varies from 0.79 × 10−3 to 1.46 × 10−3 for indoor and 0.08 × 10−3 to 0.15 × 10−3 for outdoor which is well below the safe limit of 3.5 × 10−3. The average concentration of Uranium in groundwater samples is found to be 37.95 µg/L, which is above the World Health Organisation's (WHO) standard limit of 30 µg/L. But the values of Life time average daily dose (LADD) and Hazard quotient (HQ) is found to be below the standard limit by WHO. Bones are found to be the most affected organ followed by Kidneys from the study of organ specific doses. The study suggests more intense detailed survey of Mansa district by increasing the number of sampling sites and correlate it with the other water and soil quality parameters. [ABSTRACT FROM AUTHOR]

This paper presents the implementation of a slope stability method for rainfall-induced shallow landslides in CRITERIA-1D, which is an agro-hydrological model based on Richards' equation for transient infiltration and redistribution processes. CRITERIA-1D can simulate the presence and development of roots and canopies over space and time, the regulation of transpiration activity based on real meteorological data, and the evaporation reduction caused by canopies. The slope can be considered composed of a multi-layered soil, leading to the possibility of simulating the bedrock and of setting an initial water table level. CRITERIA-1D can consider different soil horizons characterized by different hydraulic conductivities and soil water retention curves, thus allowing the simulation of capillarity barriers. The validation of the proposed physically based slope stability model was conducted through the simulation of the collected water content and water potential data of an experimental slope. The monitored slope is located close to Montuè, in the north-eastern sector of Oltrepò Pavese (northern Apennines—Italy). Just close to the monitoring station, a shallow landslide occurred in 2014 at a depth of around 100 cm. The results show the utility of agro-hydrological modeling schemes in modeling the antecedent soil moisture condition and in reducing the overestimation of landslides events detection, which is an issue for early warning systems and slope management related to rainfall-induced shallow landslides. The presented model can be used also to test different bioengineering solutions for slope stabilization, especially when data about rooting systems and plant physiology are known. [ABSTRACT FROM AUTHOR]

Clayey soils that exhibit swelling and shrinkage behaviour have paved the way for various engineering problems such as foundation failure, slope stability issues, failure of earthen dams, cracking of clay liners, etc. The shrinkage behaviour of soil is often quantified by employing various direct and indirect experimental techniques to establish the Soil Shrinkage Curve (SSC), a relationship between soil volume change and moisture content. However, SSC can reveal only the overall volume change and does not exclusively comprehend the variation of volumetric shrinkage in linear and radial directions. Hence, a series of desiccation tests were performed on marine and inland clayey soils of different consistencies to evaluate the contribution of volumetric shrinkage in these orientations. From this study, it has been observed that the linear component of volumetric shrinkage was higher for soil samples with a consistency state between 1.0 and 1.5 times the liquid limit. However, the radial component of volumetric shrinkage was found to be higher at the end of the desiccation test for soils with an initial moisture content at or below the liquid limit. Furthermore, the results obtained from the present study have been utilised to establish the influence of soil properties on radial, linear, and total volumetric shrinkage. [ABSTRACT FROM AUTHOR]

Land-atmosphere coupling is a key factor for understanding the mean hydroclimatological conditions in South America. In this study, we analyzed how land-atmosphere coupling modulates the aridity conditions in the South American continent through experiments performed with a regional climate model. We assessed changes in precipitation (P), potential evaporation (PET), aridity index (ɸ = PET / P) and vapor pressure deficit (VPD) in experiments with and without soil moisture - atmosphere coupling. Additionally, we analyzed how air dry enthalpy (Hd), moist enthalpy (Hw) and total enthalpy (Ht) change between the coupled and uncoupled experiments, which help to identify patterns in aridity conditions. When analyzing ɸ, we found opposite responses in central-eastern Brazil and southeastern South America (SESA), the two main hotspots of land-atmosphere coupling. On the other hand, a widespread amplification of VPD is found. Both VPD and enthalpy are locally driven by changes in temperature and water vapor content and reflect wetter conditions in central-eastern Brazil and drier conditions in SESA. Changes in regional circulation, described in previous studies, increase moisture convergence in Brazil and help to explain the response of each individual metric when coupling is enabled. [ABSTRACT FROM AUTHOR]

Nitric oxide (NO) is a key substance in atmospheric chemistry, influencing the formation and destruction of tropospheric ozone and the atmosphere's oxidizing capacity. It also affects the physiological functions of organisms. NO is produced, consumed, and emitted by soils, the effects of soil NO concentrations on microbial C and N cycling and associated trace gas fluxes remain largely unclear. This study describes a new automated 12-chamber soil mesocosm system that dynamically changes incoming airflow composition. It was used to investigate how varying NO concentrations affect soil microbial C and N cycling and associated trace gas fluxes under different moisture conditions (30% and 50% WFPS). Based on detection limits for NO, NO2, N2O, and CH4 fluxes of < 0.5 µg N or C m−2 h−1 and for CO2 fluxes of < 1.2 mg C m−2 h−1, we found that soil CO2, CH4, NO, NO2, and N2O were significantly affected by different soil moisture levels. After 17 days cumulative fluxes at 50% WFPS increased by 40, 400, and 500% for CO2, N2O, and CH4, respectively, when compared to 30% WFPS. However, cumulative fluxes for NO, and NO2, decreased by 70, and 40%, respectively, at 50% WFPS when compared to 30% WFPS. Different NO concentrations tended to decrease soil C and N fluxes by about 10–20%. However, with the observed variability among individual soil mesocosms and minor fluxes change. In conclusion, the developed system effectively investigates how and to what extent soil NO concentrations affect soil processes and potential plant–microbe interactions in the rhizosphere. [ABSTRACT FROM AUTHOR]

While it is established that dominant plant species of alpine meadows showed differential preference for N forms (ammonia, nitrate, and amino acids) under various degradation stages, the perseverance of the N-uptake preference and its affecting factors remains unknown. This is an important consideration because it determines efficacy of nutrient additions for restoration of degraded alpine meadows. An indoor pot experiment was conducted to investigate the plasticity and determinants of different plant species' N-uptake preference using 15N-labeled inorganic N (15NH4+ and 15NO3−) and one of dual-labeled (13C-15N) amino acid (glycine). In the experiment, dominant species of alpine meadow from specific degradation status were planted in soils of alpine meadows with three different degradation status. Most species preferred to uptake nitrate in all soils, except the Kobresia humilis, Carex moorcroftii, and Aster flaccidus planted in the soil of severely degraded alpine meadow (SD-soil) that take up more ammonia. The relative abundance of different available N forms directly affects the N-uptake preferences of all species. The partial correlations between percentage uptake and availability of various N forms were different with the zero-order correlations when either soil moisture or pH was controlled. Differences in soil moisture and pH among the three alpine meadows affects the N uptake preference of the nine species through their impacts on the relative abundance of different available N forms. In conclusion, the differences in soil moisture and pH among soils of alpine meadows under different degradation statuses influence the relative abundance of various available N forms, thereby affecting the plant N uptake. [ABSTRACT FROM AUTHOR]

Predicting soil water status remotely is appealing due to its low cost and large‐scale application. During drought, plants can disconnect from the soil, causing disequilibrium between soil and plant water potentials at pre‐dawn. The impact of this disequilibrium on plant drought response and recovery is not well understood, potentially complicating soil water status predictions from plant spectral reflectance. This study aimed to quantify drought‐induced disequilibrium, evaluate plant responses and recovery, and determine the potential for predicting soil water status from plant spectral reflectance. Two species were tested: sweet corn (Zea mays), which disconnected from the soil during intense drought, and peanut (Arachis hypogaea), which did not. Sweet corn's hydraulic disconnection led to an extended 'hydrated' phase, but its recovery was slower than peanut's, which remained connected to the soil even at lower water potentials (−5 MPa). Leaf hyperspectral reflectance successfully predicted the soil water status of peanut consistently, but only until disequilibrium occurred in sweet corn. Our results reveal different hydraulic strategies for plants coping with extreme drought and provide the first example of using spectral reflectance to quantify rhizosphere water status, emphasizing the need for species‐specific considerations in soil water status predictions from canopy reflectance. Summary Statement: We developed models to accurately predict rhizosphere water status from hyperspectral imaging of roots and soil. We found canopies cannot always accurately predict rhizosphere water status—as our experiment revealed soil–plant disequilibrium in one species (sweet corn) but not another (peanut). [ABSTRACT FROM AUTHOR]

Upon leakage in underground gas pipelines, the interaction between soil particles and gas will produce acoustic events exhibiting varied frequencies, amplitudes, and energy characteristics. In order to obtain the acoustic response of gas pipeline leaks that are buried, experiments were conducted using a two-dimensional visual leak testing facility. Employing time-domain parameter analysis, fast Fourier transform (FFT), and wavelet packet analysis (WPT), this study meticulously investigated the impact of gas pressure and soil moisture on the time-frequency characteristics of the acoustic waves throughout the leakage process. The results show that: (1) the amplitude, dominant frequency, and energy of acoustic waves closely relate to the deformation and disturbance of soil morphology, (2) the amplitude of acoustic waves increases and decreases exponentially with the increase of gas pressure and soil moisture content, respectively, (3) the main frequency response of acoustic waves during the erosion process predominantly lies within the 0 to 1 kHz range, exhibiting an "N-shaped" cyclical variation, and it tends to decrease with the increase in gas pressure and increase with the rise in soil moisture content, (4) as the leakage process continues, the energy ratio of 0–156.25 Hz increases continuously, the maximum is 45.24%, and the frequency bands of 0–156.25 Hz and 156.25–312.5 Hz demonstrate a strong responsive pattern to variations in soil moisture content and gas pressure, respectively. Therefore, these two can be utilized as the characteristic frequency bands to represent the effects of moisture content and gas pressure, and (5) the leakage acoustic sources primarily originate from pipe wall vibrations, gas impact on soil particles, and friction within the soil particle medium, with the latter two types of vibrations generating more propagative acoustic waves. The research results are of great significance to the prediction of soil structure damage and the acoustic monitoring of gas leakage. [ABSTRACT FROM AUTHOR]

Promoting arthropods in agricultural landscapes can contribute substantially to stop their decline and enhance pest control. Higher soil moisture and the presence of field margins can increase the abundance of arthropods in agricultural landscapes and influence their distribution within crop fields. However, little is known about the influence of soil moisture and distance from field margins on the overwintering of arthropods in arable fields. We investigated the influence of soil moisture and distance from a field margin on the numbers of arthropods, ground beetles and spiders emerging from soil in winter wheat fields. We established transects in winter wheat fields away from two different types of field margins: (i) around small standing water bodies (kettle holes) to capture a wide range of soil moisture values and (ii) other semi-natural landscape elements. At three distances (1 m, 20 m, 50 m), we sampled arthropods with emergence traps and measured soil moisture between March and June. We found that soil moisture had a positive effect on the emergence numbers of arthropods in general and ground beetles and spiders in particular. Distance from field margins generally had negative effects on the emergence numbers of ground beetles, but positive effects on the emergence numbers of spiders. Emergence numbers and soil moisture content did not differ significantly between the two types of field margins. The high emergence numbers inside the fields indicate that arable fields are important overwintering habitats for beneficial arthropods. Proper management of arable soils to promote soil water holding capacity and soil moisture content may have the added benefit of promoting the production of beneficial natural enemies from local soils. [ABSTRACT FROM AUTHOR]