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In permafrost regions, the strong spatial and temporal variability in soil temperature cannot be explained by the weather forcing only. Understanding the local heterogeneity of soil thermal dynamics and their controls is essential to understand how permafrost systems respond to climate change and to develop process-based models or remote sensing products for predicting soil temperature. In this study, we analyzed soil temperature dynamics and their controls in a discontinuous permafrost region on the Seward Peninsula, Alaska. We acquired one-year temperature time series at multiple depths (at 5 or 10 cm intervals up to 85 cm depth) at 45 discrete locations across a 2.3 km2 watershed. We observed a larger spatial variability in winter temperatures than that in summer temperatures at all depths, with the former controlling most of the spatial variability in mean annual temperatures. We also observed a strong correlation between mean annual ground temperature at a depth of 85 cm and mean annual or winter season ground surface temperature across the 45 locations. We demonstrate that soils classified as cold, intermediate, or warm using hierarchical clustering of full-year temperature data closely match their co-located vegetation (graminoid tundra, dwarf shrub tundra, and tall shrub tundra, respectively). We show that the spatial heterogeneity in soil temperature is primarily driven by spatial heterogeneity in snow cover, which induces variable winter insulation and soil thermal diffusivity. These effects further extend to the subsequent summer by causing variable latent heat exchanges. Finally, we discuss the challenges of predicting soil temperatures from snow depth and vegetation height alone by considering the complexity observed in the field data and reproduced in a model sensitivity analysis.

The stability of side walls in terraced fields constructed within expansive soil regions represents a critical challenge, often leading to structural failure due to the unique wetting–swelling behavior of the soil. This study employs a comprehensive approach, integrating analytical and numerical methods to elucidate the mechanism of overturning failure attributed to the swelling effect of expansive soil under conditions of layer‐by‐layer saturation. Initially, the earth pressure acting on side walls, constructed from fiber ecological bags, is assessed in their natural, unsaturated state using Bishop's formula for unsaturated shear strength. The study further explores the failure mode through one‐dimensional analytical analysis, focusing on the horizontal and unrestrained expansion of expansive soil during progressive saturation. Subsequently, the deformation of the side wall and the swelling effect of the soil are numerically evaluated. This is achieved by analogizing the wetting–swelling deformation field in expansive soil to an equivalent temperature field, thereby facilitating the use of finite element numerical simulation to investigate the overturning failure mechanism. Findings indicate that in the natural unsaturated state, the side walls remain stable under no earth pressure. However, as saturation depth attains a critical depth of 1.4 m during layer‐by‐layer saturation, the upper wall rotates outward in the form of local overturning failure, and the corresponding infiltration saturation depth is the critical depth for the local instability of the side wall. The investigation identifies the wetting–swelling effect as the predominant factor leading to the structural failure of side walls in terraced fields situated in expansive soil areas. Moreover, a critical infiltration saturation depth of 2.6 m is determined, beyond which the stability of the side walls is compromised. This research contributes significantly to the understanding of the failure mechanisms affecting terraced agricultural infrastructures in expansive soil regions, offering a theoretical foundation for the development of more resilient construction strategies. [ABSTRACT FROM AUTHOR]

Changes in the soil freeze–thaw status will inevitably affect the thermal conditions and properties of the Tibetan Plateau (TP), thereby affecting its upper atmosphere, and further afield in East Asia and even globally. In this study, using the soil temperature simulated by the Community Land Model Version 5.0 (CLM5.0), the timing and duration of the soil freeze–thaw status were divided into freeze start‐date, freeze end‐date and freeze duration. Then, using linear trend estimation, correlation analysis and other methods, the changes in the spatiotemporal distribution of the timing and duration of the soil freeze–thaw status from 1979 to 2018 over the TP were analysed, and the relationships between them and surface temperature, altitude and latitude were analysed. The results obtained were as follows: (1) The soil temperature simulated by CLM5.0 can reasonably reproduce the seasonal changes in multilayer soil temperature, and correlated well with observations. Simulated by CLM5.0 of the time and duration of the soil freeze–thaw status also correlated well with observations. (2) The spatial distribution of the soil freeze–thaw status is characterized by a trend of delayed freezing, advanced thawing and shortened freeze duration from northwest to southeast over the TP. From 1979 to 2018, the freeze start‐date postponed by 7.3 days and became delayed at a rate of 1.9 days per decade, while the freeze end‐date advanced by 6.4 days at a rate of 1.7 days per decade, and the freeze duration shortened by 13.7 days at a rate of 3.6 days per decade. The timing and duration of the soil freeze–thaw status vary across different regions of the TP. The freeze start‐date in all areas of the TP has been delayed in the past 39 years. Except for the subcold zone and arid regions of the TP, the freeze end‐date has occurred earlier and the freeze duration has shortened, with the most significant changes in the subcold zone and humid regions, while the freeze end‐date has advanced at a rate of 3.6 days per decade and the freeze duration has shortened at a rate of 6.3 days per decade. (3) The timing and duration of the soil freeze–thaw status are significantly correlated with surface air temperature, elevation and latitude, exceeding the 99% confidence level. The correlation between the timing and duration of the soil freeze–thaw status and surface temperature is strongest, followed by altitude, and correlation with latitude is weaker. The correlation between surface air temperature and the timing and duration of the soil freeze–thaw status in the western TP is stronger than that in the eastern TP. The rate of change in the soil freeze–thaw status increases with altitude to 3000 m above sea level, while this rate decreases with elevation above 3000 m. The rate of change in the soil freeze–thaw status is greatest at 29°N, while the rate of delay in the freeze start‐date is minimal at 33°N and the rates of advancement in the freeze end‐date and shortening of the freeze duration are minimal at 35°N. [ABSTRACT FROM AUTHOR]

Litter decomposition in mountainous forest ecosystems is an essential process that affects carbon and nutrient cycling. However, the contribution of litter decomposition to terrestrial ecosystems is difficult to estimate accurately because of the limited comparability of different studies and limited data on local microclimatic and non‐climatic factors. Here, we designed a coordinated experiment within subtropical and tropical forests across ten mountains to evaluate variation in litter decomposition rates and stabilization. We tested whether elevations, soil microclimate, soil physiochemistry, tree species diversity, and microhabitat affect decomposition rates and stabilization by using the Tea bag index as a standardized protocol. We found that the associations of decomposition rates and stabilization with elevation and each environmental factor varied between mountains. Elevation significantly affected decomposition rates and stabilization in the western mountains, where soil microclimate also played a dominant role due to relatively cold environments. Across all mountains, decomposition rates decreased while stabilization increased with increasing elevation. In terms of microclimate, decomposition rates increased with increasing soil temperature and temperature variation during the growing season, whereas stabilization decreased with increasing soil temperature and moisture variation. In terms of non‐climatic factors, decomposition rates increased with increasing tree species diversity, whereas stabilization decreased with soil pH and slope. Our findings enhance the general understanding of how different factors control forest litter decomposition, highlighting the dominant role of soil microclimate in controlling carbon and nutrient cycling in cold environments and high elevations. [ABSTRACT FROM AUTHOR]

Bonding of soil grains can be achieved by melting added polymer particles initially mixed with dry soil. Salient challenges associated with conventional external heating via boundary conduction include long treatment durations and inhomogeneous bonding. The current study aims to overcome these challenges via the use of microwaves to induce quick internal heating. Results of experiments on sand-silt specimens that contain a 10% fraction of natural microwave susceptor grains confirmed that internal heating produces homogeneous bonding much quicker than external heating (by a factor of 20), particularly when the target soil mass is relatively large. The tensile strength (qt) of specimens bonded via microwave heating was found to be inversely proportional to their fines content (FC), although the temperatures sustained by soils increased with increasing FC. Bonded specimens subject to a wetting–drying cycle exhibited lower tensile strengths than the unwetted counterparts. Yet, specimens subject to reexposure to microwaves after a wetting–drying cycle exhibited tensile strengths of at least 85% that of analogous unwetted specimens. The power penetration depth for 2.45 GHz microwaves was calculated to be 0.5 m

Aim: The scale of environmental data is often defined by their extent (spatial area, temporal duration) and resolution (grain size, temporal interval). Although describing climate data scale via these terms is appropriate for most meteorological applications, for ecology and biogeography, climate data of the same spatiotemporal resolution and extent may differ in their relevance to an organism. Here, we propose that climate proximity, or how well climate data represent the actual conditions that an organism is exposed to, is more important for ecological realism than the spatiotemporal resolution of the climate data. Location: Temperature comparison in nine countries across four continents; ecological case studies in Alberta (Canada), Sabah (Malaysia) and North Carolina/Tennessee (USA). Time Period: 1960–2018. Major Taxa Studied: Case studies with flies, mosquitoes and salamanders, but concepts relevant to all life on earth. Methods: We compare the accuracy of two macroclimate data sources (ERA5 and WorldClim) and a novel microclimate model (microclimf) in predicting soil temperatures. We then use ERA5, WorldClim and microclimf to drive ecological models in three case studies: temporal (fly phenology), spatial (mosquito thermal suitability) and spatiotemporal (salamander range shifts) ecological responses. Results: For predicting soil temperatures, microclimf had 24.9% and 16.4% lower absolute bias than ERA5 and WorldClim respectively. Across the case studies, we find that increasing proximity (from macroclimate to microclimate) yields a 247% improvement in performance of ecological models on average, compared to 18% and 9% improvements from increasing spatial resolution 20‐fold, and temporal resolution 30‐fold respectively. Main Conclusions: We propose that increasing climate proximity, even if at the sacrifice of finer climate spatiotemporal resolution, may improve ecological predictions. We emphasize biophysically informed approaches, rather than generic formulations, when quantifying ecoclimatic relationships. Redefining the scale of climate through the lens of the organism itself helps reveal mechanisms underlying how climate shapes ecological systems. [ABSTRACT FROM AUTHOR]

On February 17 2023, a landslide occurred on a highway slope along the Xiaolangdi Reservoir of the Yellow River, involving approximately 1,200 m3. This event directly resulted in road interruption and had profound social repercussions. This paper researches the landslide using a combination of field investigation, remote sensing imagery, laboratory tests, and numerical simulation. It traces the evolution of landslide occurrences influenced by human engineering activities and investigates the mechanisms by considering climatic factors, water levels fluctuations, and stress changes. The results indicate that: (1) fluctuations in water levels can reduce the stability coefficient of ancient landslides, albeit without directly triggering them. Moreover, alterations in soil stress induced by artificial excavation changes the distribution of the slope plastic zone, consequently altering potential sliding zones. (2) rainfall and temperature emerge as primary factors influencing the occurrence of accumulation landslides, it is particularly susceptible with the transition between winter and spring. (3) freeze-thaw action exerts significant pressure on sandstone bedding, which causes notable expansion deformation. Consequently, it is advisable to consider soil temperature and bedrock deformation when monitoring similar slopes. [ABSTRACT FROM AUTHOR]

Purpose: A prerequisite for the successful application of phytoliths in paleoenvironmental reconstruction is the correct interpretation of their environmental significance. In this context, key questions include: What magnitude of temperature/precipitation change is required to effect significant changes in surface soil phytolith percentages? When temperature/precipitation increases by a certain amount, what is the corresponding response of the percentages and assemblages of surface soil phytoliths? Additional detailed research is required to answer these questions. Materials and methods: We analyzed the phytoliths in 90 surface soil samples collected along the isohyets corresponding to the mean annual precipitation (MAP) of 400 mm (with the mean annual temperature (MAT) range of 3.24℃) and 600 mm (with the MAT range of 8.29℃) in Northeast China. Our objective was to determine the response of phytoliths to different temperature gradients. Soil phytoliths were extracted and identified using heavy liquid separation and microscope observations. Results: The DA of the phytolith percentages enabled the separation of samples collected along the two isohyets, with a total accuracy of 94.44%. MAT was the principal factor affecting the spatial distribution of phytoliths, with an explanation rate of 46.40%. In the surface soil samples collected along the two isohyets, the percentages of ELONGATE, ACUTE BULBOSUS, and PTERIDOPHYTE-TYPE morphotypes, were significantly negatively correlated with MAT, while the percentages of SQUARE were significantly positively correlated with MAT. However, the relationship between PAPILLATE percentages and MAT varied, showing both positive and negative correlations. A temperature gradient of ~ 3℃ was insufficient to significantly affect the percentages of SADDLE, BULLIFORM FLABELLATE, and BILOBATE. The phytolith index (C/W) can be effectively used to reconstruct the palaeoclimate in Northeast China. An MAP change of 200 mm resulted in significant changes in the percentages of ELONGATE, SADDLE, BULLIFORM FLABELLATE, and TRACHEARY (with the respective rates of 39.57%, 780.77%, 179.00% and 81.25%). However, the percentages of ACUTE BULBOSUS, SQUARE, RONDEL, BILOBATE, CRENATE, PTERIDOPHYTE-TYPE, SILICIFIED STOMATA, and PAPILLATE did not change significantly. Conclusions: Our results contribute to an improved understanding of the response of various phytolith morphotypes to temperature, and they provide a modern process basis for future phytolith-based paleoclimatic reconstruction in this region. [ABSTRACT FROM AUTHOR]

AbstractElectroosmosis (EO) has been well recognized as a technique for drainage and consolidation in soft soil, however, the presence of an ice phase in frozen soil at subzero temperatures introduces considerable complexity to the electroosmotic process. To investigate the influence of ambient temperature effect on the frozen soil electroosmosis, a series of laboratory tests were conducted under four ambient temperatures (AT) conditions. Taking into account the influence of soil composition, silty clay (Clay) and silt (Loess) were selected. Experimental procedures involved the measurement of current and temperature, with subsequent analysis focusing on comparisons of moisture content changes. The results indicated that the moisture migration of frozen Loess is more obvious than that of Clay. Meanwhile, moisture migration is significantly influenced by soil particle size, and as ambient temperature decreases, the impact of soil particles on moisture migration in frozen soil diminishes gradually. Moisture migration mainly occurs within the first 30 h after power-on on and the speed of moisture migration gradually decreases with the extension of power-on time. This study contributes novel insights and a basis for the in-depth understanding of permafrost seepage and the treatment of permafrost pollution. [ABSTRACT FROM AUTHOR]

Forest fires and burn offs generate high soil temperatures, mineralizing organic matter and trapping it in the form of charcoal. A system that can catalyze its liberation in the absence of bacteria is a technological innovation that accelerates the recovery of these soils. We evaluated the parameters of nitrogen, potassium, and phosphorus in ashes from wood, charcoal, and burned earth. We observe that using the TCAS‐CATA catalyst in a 1% V/V solution generated a threefold increase in the concentration of nitrogen, phosphorus and potassium (NPK) parameters in the solutions. Using this solution on land with low fertility increased values for organic soil richness, as evaluated by NPK rising by over three times the basal rate. These data indicate that using this TCAS‐CATA helps recover nutrients from carbonized material, improves soil, and aids it in recovery in less time. [ABSTRACT FROM AUTHOR]

Key message: Winter reddening of young Douglas-fir (Pseudotsuga menziesii Mirb. Franco), triggered by large thermal fluctuations in late winter, is a critical problem for European forestry. A literature review identified certain climatic conditions that are characteristic of 'reddening' years, including warm daily temperatures, high daily temperature amplitude, low relative humidity, moderate wind speeds, as well as the occurrence of freeze-thaw cycles with cold night temperatures. By describing the triggering environmental and stand factors, we propose three hypotheses for the physiological processes leading to winter reddening, namely (i) hydraulic failure due to winter drought stress, (ii) photo-oxidative stress in shade-acclimated trees, and (iii) early cold deacclimation during warm periods. i) Low soil temperature, by reducing root water uptake, combined with anticyclonic conditions, by increasing water losses, can induce hydraulic failure in the xylem. Hydraulic failure may be further accelerated by night frosts. ii) Winter reddening can occur when low temperature and high irradiance coincide, disrupting photostasis. Overwhelming of winter photo-protection may lead to photodamage and subsequent reddening. iii) Warm periods, by inducing cold deacclimation, make trees susceptible to frost damage. Finally, the three processes may interact under atypical anticyclonic conditions in late winter (e.g. cold or dry soils, warm days, high irradiance and/or freezing nights). Indeed, trees under water stress would develop a higher sensitivity to freezing night and photooxidative stress. We therefore proposed mitigation actions to avoid exposing trees to stressful conditions based on e.g. stand characteristics, understorey vegetation and planting. [ABSTRACT FROM AUTHOR]

Specific leaf area (SLA) and leaf dry matter content (LDMC) are key leaf functional traits often used to reflect plant resource utilization strategies and predict plant responses to environmental changes. In general, grassland plants at different elevations exhibit varying survival strategies. However, it remains unclear how grassland plants adapt to changes in elevation and their driving factors. To address this issue, we utilized SLA and LDMC data of grassland plants from 223 study sites at different elevations in China, along with climate and soil data, to investigate variations in resource utilization strategies of grassland plants along different elevational gradients and their dominant influencing factors employing linear mixed-effects models, variance partitioning method, piecewise Structural Equation Modeling, etc. The results show that with increasing elevation, SLA significantly decreases, and LDMC significantly increases (P < 0.001). This indicates different resource utilization strategies of grassland plants across elevation gradients, transitioning from a "faster investment-return" at lower elevations to a "slower investment-return" at higher elevations. Across different elevation gradients, climatic factors are the main factors affecting grassland plant resource utilization strategies, with soil nutrient factors also playing a nonnegligible coordinating role. Among these, mean annual precipitation and hottest month mean temperature are key climatic factors influencing SLA of grassland plants, explaining 28.94% and 23.88% of SLA variation, respectively. The key factors affecting LDMC of grassland plants are mainly hottest month mean temperature and soil phosphorus content, with relative importance of 24.24% and 20.27%, respectively. Additionally, the direct effect of elevation on grassland plant resource utilization strategies is greater than its indirect effect (through influencing climatic and soil nutrient factors). These findings emphasize the substantive impact of elevation on grassland plant resource utilization strategies and have important ecological value for grassland management and protection under global change. [ABSTRACT FROM AUTHOR]

Using tomato as experimental materials, the effects of different straw reactor treatments on soil temperature, carbon dioxide flux and tomato plant growth, yield and quality were studied. The results showed that compared with the inter-row straw reactor treatment, the in-row straw reactor treatment could increase the soil temperature of tomato greenhouse by 3.1-4.5 ℃. The treatment technology of the in-row straw reactor could effectively solve the CO2 deficit in the solar greenhouse in the morning and afternoon on sunny days, significantly improve the plant height, stem diameter, chlorophyll content, leaf photosynthetic characteristics, and vitamin C content, free amino acids, soluble protein, soluble sugar and lycopene content of tomato at different growth stages, and reduce nitrate content. The yield of tomato in row reactor increased by 5.18%. Straw reactor increased soil temperature and promoted plant growth, which could promote the color transformation of tomatoes 15-20 days earlier and promote the early market of tomatoes. BR treatment had the best effect, followed by BR-S and BR-D. [ABSTRACT FROM AUTHOR]

The impact of land variables on temperature forecasts in atmospheric cycling is often underestimated or overlooked. This oversight primarily occurs due to the abundance of meteorological measurements available for assimilation and partly because soil states are assumed to be quickly reset by atmospheric forcing, such as precipitation, justifying no spin‐ups or no updates of soil states during cycling. In this study, by updating soil moisture every 6 hr using different analysis data sets for May 2019, considerable discrepancies were found, highlighting large uncertainties in soil moisture analysis. Different soil moisture analyses produced systematically different temperature forecasts, with errors growing over cycles to be comparable to a typical error magnitude of 2‐m temperature observations (∼2°K). This study demonstrates that temperature forecasts are significantly influenced by whether and how soil moisture is updated, not only near the surface but also up to the low‐mid troposphere and throughout the cycles. Plain Language Summary: This study examines the impact of soil moisture on temperature forecasts in the context of atmospheric cycling. During the 6‐hr cycling for May 2019 over the CONUS domain, updating soil moisture systematically affects temperature forecast bias (>±1°K) in the low‐mid troposphere throughout the cycles. We also observe significant uncertainties across state‐of‐the‐art soil moisture analysis data sets, highlighting the challenges of land data assimilation. Key Points: Temperature forecast errors are significantly affected by whether or how soil moisture is updated in atmospheric cyclingLarge uncertainties are found across different soil moisture analysis data setsUpdating soil moisture alone can mitigate temperature forecast bias in the low‐mid troposphere, systematically improving forecast accuracy [ABSTRACT FROM AUTHOR]

An open field experiment from November 2022 to May 2023 in Croatia, which is characterized by a continental humid climate, evaluated nonwoven mulches made from viscose, jute, and hemp fibres blended with PLA fibres. The blends of viscose and jute fibres (90:10, 80:20, and 70:30 ratios) were produced using mechanical web formation on cards with needle punching for bonding webs. Additionally, hemp fibres were blended with PLA fibres in a ratio of 80:20. Winter conditions caused significant structural changes in the mulches, including shrinkage, increased mass per unit area, thickness, and reduced air permeability. The amount of PLA fibre in the nonwoven mulch blends significantly affected nonwoven fabric structure change during exposure to winter conditions. After 180 days, the breaking force of all mulches increased by 30% to 277%. The soil beneath jute and hemp mulches maintained higher temperatures and moisture levels compared to viscose mulches. Soil organic carbon content varied with fibre type and was higher under jute and hemp mulches. K2O content was significantly higher in soils covered by mulches. All mulches effectively suppressed weeds. The experiment results showed that the newly produced nonwoven mulches could replace the conventional agro foil. Results also suggest that choosing biodegradable nonwoven mulches produced from fibres obtained from natural and renewable sources can influence soil fertility and the availability of nutrients, ultimately affecting plant growth and agricultural productivity. [ABSTRACT FROM AUTHOR]

Litter decomposition is a vital part of the carbon cycle and is thoroughly studied both in the field and with models. Although temporally and spatially limited, litterbag decomposition experiments are often used to calibrate and evaluate soil models, coupled to land models, that are intended for use on large scales. We used the microbially explicit soil decomposition model MIMICS+ to replicate two high-latitude litterbag decomposition experiments of different spatial and temporal scales. We investigated how well the model represented observed mass loss in terms of the controlling factors of climate and litter quality and their relative importance with time. In addition to default model forcing, we used measured and site-specific model-derived microclimatic variables (soil moisture and temperature), hypothesizing that this would improve model results. We found that MIMICS+ represented mass loss after 1, 3, and 6 years well across a climatic gradient of Canadian sites but had more variable results for 1-year mass loss across a climate grid in southern Norway. In terms of litter quality, the litter metabolic fraction had more influence on modeled mass loss than the carbon-to-nitrogen ratio of the litter. Using alternative microclimate sources led to up to 23 % more mass remaining and down to 22 % less mass remaining compared to the simulations using default model inputs. None of the input alternatives significantly improved results compared to using the default model setup. We discuss possible causes for our findings and suggest measures to better utilize short-term field experiments to inform microbially explicit decomposition models. [ABSTRACT FROM AUTHOR]

Soil temperature is a key parameter in many disciplines, and its research has important practical significance. In recent years, the prediction of soil temperature by deep learning has achieved good results. However, deep learning is difficult to popularize in practical use because of its opacity. This study aims to interpret and analyze the Long Short Term Memory Network (LSTM) model for global soil temperature prediction using SHapley Additive exPlanation (SHAP), Permutation Importance (PI) and Partial Dependence Plot (PDP). The results show that Temperature of air at 2 m above the surface of land has the greatest influence on the prediction of soil temperature, and its SHAP and PI characteristic values have significant seasonality. Meanwhile, radiation also has a certain influence on the prediction results. There was a significant positive correlation between the temperature of 2 m and the soil temperature. The explanatory insights provided in this paper enhance the transparency and confidence of the model, which promotes the applicability of soil temperature prediction models in relevant fields. [ABSTRACT FROM AUTHOR]

Changes in trends and variabilities of precipitation, temperature, and evaporation are some of the pronounced effects of climate change. This study assessed the effects of precipitation and temperature trends and variabilities on soil moisture storage. Forty-one years' historical data on precipitation, temperature, and soil moisture were collected for four agrarian local government areas in southern and northern Nigeria. Trend changes and variabilities were analyzed using the Mann Kendall, modified Mann Kendall, Palmer drought severity index, standardized precipitation evaporation index, standardized precipitation index, and temperature indices. Observed precipitation in the northern part experienced very significant decrease and both the southern and northern divides experienced significant temperature increase over the last four decades. However, the temperature indices including hottest days (TXx), summer day (SU35), and diurnal temperature range (DTR) indicated northern Nigeria experienced more extreme temperature increase and thus more drought than southern Nigeria. The northern part had averages TXx, SU35, and DTR of 39.66 °C, 66.49 days, and 17.99 °C, while the southern part had 33.61 °C, 0.075 days, and 9.47 °C, respectively. The continuous increase in temperature and precipitation decrease are attributable to climate change caused by ozone layer depletion. Low precipitation and high temperature resulted to significant reduction of soil moisture storage in northern Nigeria, while soil moisture reductions were limited in southern Nigeria. Effects of temperature and precipitation trends on soil moisture trends therefore emphasize the need for proper water management, continuous soil moisture conservation, and intense irrigation practices, to enhance food production and security. [ABSTRACT FROM AUTHOR]

Introduction: Planting without mulching can eliminate the residual film pollution caused by the long-term use of plastic film covers, but it will increase soil moisture evaporation and heat loss and severely reduce water use efficiency and cotton productivity in cotton (Gossypium hirsutum L.) fields in arid regions. It is unclear whether the advantages of subsurface drip irrigation and nighttime irrigation can be leveraged to reduce the amount of irrigation applied in fields, improve the soil and leaf hydrothermal environments, and increase the synchronicity of yield and water use efficiency (WUE). Methods: Therefore, in a two-year field experiment (2019-2020), cotton was grown under different irrigation treatments (I5, 3753 m3 ha-1; I4, 3477 m3 ha-1; I3, 3201 m3 ha-1; I2, 2925 m3 ha-1; and I1, 2649 m3 ha-1). The soil volumetric moisture content, soil temperature, leaf relative water content (RWC), daily changes in gas exchange parameters, lint yield, and WUE were evaluated. Results and discussion: The results showed that reducing irrigation can reduce the soil volumetric moisture content (0-40 cm soil layer), increase the soil temperature and soil temperature conductivity, and increase the leaf temperature, intercellular carbon dioxide concentration (Ci), and WUE; however, reducing irrigation is not conducive to increasing the leaf RWC, net photosynthetic rate (Pn), stomatal conductance (Gs), or transpiration rate (Tr). There was no significant difference in WUE between the I3 and I4 treatments from 8:00 to 20:00, but the lint yield in these treatments increased by 2.8-12.2% compared to that in the I5 treatment, with no significant difference between the I3 and I4 treatments. In addition, a related analysis revealed that the positive effects of the leaf hydrothermal environment on the Pn and soil temperature on the WUE occurs during the same period (10:00-16:00). Overall, an irrigation amount of 3201-3477 m3 ha-1 applied with a subsurface nighttime irrigation system without mulching can enhance the soil moisture content and soil temperature, maintain a high photosynthetic capacity, and increase the lint yield and WUE. These results revealed that the negative impacts of plastic film contamination in arid areas can be alleviated. [ABSTRACT FROM AUTHOR]

A novel BHEs is proposed that can overcome the problems associated with the low heat-transfer efficiency of borehole heat exchangers (BHEs) that are connected in series (BHEs-S) and the low heat-transfer temperature differences of BHEs that are connected in parallel (BHEs-P). The new BHE uses a combined series and parallel connection (BHEs-CSP), which can further be classified into individual in-series and in-parallel zones. A numerical model of the new BHEs-CSP is then developed to optimize the key design parameters such as borehole spacing, number of series stages, and heat-extraction methods. The results show that, with the optimal configuration, the average soil temperature with a BHEs-CSP is 6.70°C higher than for a BHE that is connected in parallel. Furthermore, the heat-transfer efficiency can be improved by 4.1% compared to BHEs that are connected in series. It is recommended that the distance between buried pipes in the series area and parallel area should be 5.25 m, and the series number of buried pipe groups should be 4. To study the overall performance of the solar-assisted ground-source heat-pump with a BHEs-CSP (SAGSHP-CSP), a TRNSYS model is developed. The results show that the optimal area- and heat-storage-ratios (for in-series zone to inparallel zone), using SAGSHP-CSP, are 1:4 and 3:2, respectively. Under these conditions, the system coefficient of performance (SCOP) is over 5.2 and the COP and SCOP is improved by 9.8% and 13.0% compared to GSHP systems with BHEs-P. Furthermore, an improvement by 18.4% and 18.2%, compared to the GSHP system with BHEs-S, is reported. [ABSTRACT FROM AUTHOR]

Filtering processes across environmental gradients can structure patterns of trait variation within communities. The community‐weighted mean (CWM) is a metric that is commonly used to indicate the directionality of such filtering processes and the optimal adaptive strategy of taxa within community. Proximity to the CWM indicates higher fitness, and deviations from this optimal value result in changes in the relative abundances of coexisting species. We investigated patterns of intraspecific trait variation in four coexisting carrion beetle species (Coleoptera: Silphidae) across elevational gradients. The study was conducted in temperate forest ecosystems with distinct natural vegetation zones ranging from 950 m to 1700 m above sea level. Of the 12 traits measured, we found that intraspecific variation ranged from 34% (body length) to 100% (ratio of elytra length, head length and head width to body length) and accounted for a larger proportion of variation than interspecific variation in 7 traits. For most traits, trait range, which indicates the niche breadth of species at a given elevation, was positively correlated with relative abundance. The CWMs of traits associated with long‐distance dispersal decreased with elevation, whereas those associated with microhabitat use showed the opposite trend. Soil temperature influenced tibia length after controlling for the effects of species identity, but soil water content had no effect on trait variation. Patterns of variation in body width and thorax width of two beetle species supported the CWM‐optimality hypothesis; however, patterns of trait variation in body width and thorax length of another species showed an opposite trend. Our study identifies several traits that can be highly variable within carrion beetle species. Such high levels of intraspecific trait variation may enable populations to adapt across a wide range of elevations and vegetation types. [ABSTRACT FROM AUTHOR]

Background Aims Methods Results Conclusion Incorporation of cover crop (cc) shoot and root biomass can have different effects on nitrogen (N) dynamics and the transformation of soil‐derived N and cc N.The objective was to determine the effects of different ccs, cc compartments (roots and shoots), and pretreatment of cc biomass (fresh vs. dried) on mineralization processes and on the transformation of soil and cc N following incorporation into a silty loam soil.Soil columns with incorporated 15N‐labeled root and shoot biomass of two cc species (winter rye and oil radish) and different pretreatments (dried and fresh) were incubated for 70 days at a constant temperature and soil moisture (8°C, 40% water‐filled pore space). Carbon and N transformation dynamics were determined repeatedly, distinguishing between N originating from cc biomass and from soil.Net CO2 emission was related to the amount of soluble cell components added with ccs. Net N mineralization was negatively related to the C:N ratio of cc biomass. The incorporation of dried cc biomass caused higher initial soil respiration and N immobilization than fresh biomass. All treatments with cc incorporation showed increased N2O emission. Emitted N2O‐N consisted mainly of cc N (55%–57%) in treatments with fresh shoot biomass, whereas soil N was the main source of N2O (75%) in the treatment with fresh oil radish roots. Recovery of cc 15N was affected by crop compartment and pretreatment. At the end of the incubation, it was 17.5%–42.3% in soil NO3−, 0.1%–8.1% in microbial biomass N, and less than 0.23% of cc N was found in cumulative N2O emission.The incorporation of cc roots and shoots had different effects on N mobilization and immobilization processes and on the partitioning of cc N. These processes can be influenced significantly by pretreatment of the added plant biomass (dried vs. fresh). [ABSTRACT FROM AUTHOR]

Drained peat soils (Histosols) were studied. In the mode of weak and moderate drainage, the trend of seasonal fluctuations (quadratic parabola) shows a weekly average increase in dehydrogenase activity with a weekly average deceleration, and in the intensive drainage mode, a weekly average deceleration with a weekly acceleration for June–October. A significant nonlinear relationship of enzyme activity was revealed: positive with redox potential and pH, and multidirectional with soil bulk moisture and soil temperature. According to canonical analysis, the discussed set cumulatively determines the seasonal dehydrogenase activity by 50–81%. The hydrological regime is statistically proved as a dominant factor. A negative conjugate interaction of dehydrogenase and peroxidase activity has been established, confirming their participation in the biochemical transformation of organic matter as a whole. [ABSTRACT FROM AUTHOR]

There is growing interest in using canopy temperature (Tc), including crop water Stress index (CWSI), for irrigation management. However, Tc varies greatly in one day, while soil water content (SWC) varies little, which may lead to different conclusions on whether irrigation is needed based on CWSI at different times. For this end, Tc of winter wheat was continuously monitored, and the data of such environmental factors as atmospheric temperature and soil water content (SWC) were simultaneously collected. CWSI was calculated based on empirical formulation and Tc and CWSI were generalized based on the normalization formulation. The correlation SWC between Tc and CWSI before and after generalization was compared and error analysis was based on SWC theoretical formula. The results showed: (1) the accuracy of SWC retrieval by Tc and CWSI increased firstly and then decreased with time during the day. The optimal time for Tc monitoring SWC was between 10:00 ~ 16:00 (R2 > 0.72) and the optimal time for CWSI monitoring SWC was between 9:00 ~ 18:00 (R2 > 0.69). (2) CWSI and Tc were mapped based on the relationship between crop water stress and soil water deficit and normalized canopy temperature expressions characterized the relationship between crop water stress and soil water deficit. (3) The accuracy of inversion of SWC by mapping Tc from 18:00 ~ 8:00 is increased from 0.5 ~ 0.6 to 0.7 ~ 0.8; the accuracy of soil water content inversion by mapping CWSI from 18:00 ~ 8:00 was improved from 0.2 ~ 0.4 to 0.4 ~ 0.6. (4) The theoretical expression of SWC deduced based on CWSI also proves that considering the relationship between crop water stress and soil water deficit change can effectively reduce the relative error from 30 to 5% in the morning and evening. This study contributes to the understanding of the reason why the correlation between Tc and SWC varies greatly during the day and solves the time-limited problem of thermal infrared remote sensing monitoring of crop water stress. [ABSTRACT FROM AUTHOR]

Aims: Balancing yield and soil CO2 emissions in cropping systems has become a focus of agricultural research. To explore effective ways to achieve the balance, three years (2016–2018) of field experiments were conducted in the oasis zone of Northwest China. Methods: Three replications of the four tillage systems (NT, no-tillage; MT, minimal-tillage; ST, sub-tillage; FT, fold-tillage) were used in a randomized complete block design. Results: It was found that tillage practice had no significant effect on soil carbon pools. However, FT exhibited a significantly higher soil carbon emission intensity (SCEI) and net ecosystem primary productivity (NPP). Still, poorly in terms of net ecosystem productivity (NEP) than those of the NT, MT, and ST treatments, MT performed the highest NEP and maize yield (P < 0.05). The total cumulative CO2 emissions of the FT were 23.3%-37.6% higher than those of the other tillage practices. Furthermore, we identified that soil CO2 emission was mainly influenced by soil temperature and soil moisture. NT increased farmers' net income and output/input ratio by 20.2% and 41.3% respectively compared with FT and demonstrated better economic benefits and net ecosystem productivity. Conclusions: The results suggest that conservation tillage (especially NT and MT) is advantageous to local economic and ecological benefits in the short term. However, the years of continuous tillage are critical for increasing crop yields and reducing CO2 emissions, so the feedback response of long-term tillage on farmland still needs to be observed and studied. [ABSTRACT FROM AUTHOR]

Background and aims: Forest management practices affect soil carbon dynamics, particularly by changing the diversity of aboveground plant functional groups. However, we have a limited understanding of the underlying mechanisms for how plant management affects soil respiration in planted forest ecosystems. Methods: We conducted a 3-year manipulation experiment of plant functional groups that included understory removal, tree root trenching, and fertilization treatments in 2-year-old and 6-year-old Eucalyptus plantations in the subtropical region, to explore the responses of soil carbon emission and microbial community composition. Results: Soil respiration was significantly suppressed by understory removal (-38%), tree root trenching (-41%), and their interactions (-54%), but fertilization alone and in interactions had no significant effect. Soil bacterial and fungal diversity was negatively affected by understory removal and tree root trenching, respectively. Soil respiration and microbial diversity were lower in younger plantations. Reductions in soil carbon emissions were associated with losses of plant functional groups and soil microbial diversity, while increases in soil respiration were associated with soil physicochemical factors, soil temperature, and plantation age. Conclusions: The results indicated that understory removal and tree root trenching strongly affected soil respiration, while the power effects were regulated by soil microbial community and soil properties in contrast plantation ages. Our findings highlight that plant management is of great significance to the soil carbon emission processes in afforested plantations. [ABSTRACT FROM AUTHOR]

An understanding of how boreal forest composition responds to global environmental changes is an important challenge to predicting the future global carbon balance. Boreal forests are the most significant sink for atmospheric carbon dioxide; however, their sequestration capacity is highly sensitive to ongoing climate changes. The combination of the hydrothermal conditions of a territory strongly regulates its biogeochemical processes. The carbon fluxes in boreal forests are strongly mediated by the ground vegetation cover, composed of mosses (mesic) and lichens (xeric). Despite the concurrence of xeric and mesic vegetation types, their responses to climate variations varies significantly. Soil emission is an informative indicator of ecosystem functioning. In this study, we focused on the soil CO2 dynamics during frost-free seasons with different precipitation regimes in the xeric and mesic boreal ecosystems of Central Siberia. Seasonal measurements of soil CO2 emissions were conducted during frost-free seasons using the dynamic chamber method. Our findings reveal that the precipitation regimes of each year may control the seasonal soil emission dynamics. The soil moisture is the most important driver of emissions growth in the water-limited lichen pine forest (R2adj. = 18%). The soil temperature plays the largest role in the feather moss pine forest during the dry (R2adj. = 31%) seasons, and in the lichen pine forest during the wet (R2adj. = 41%) seasons. The cumulative efflux for the xeric and mesic sites is mostly related to the hydrothermal conditions, and not to the differences in ground vegetation cover. During the dry seasons, on average, the soil CO2 emissions are 45% lower than during the wet seasons for both sites. These findings emphasize the need for estimating and including the hydrothermal characteristics of the growing season for detailed emission assessments. [ABSTRACT FROM AUTHOR]

Background: There is evidence that global anthropogenic climate change may be impacting floral phenology and the temporal and spatial characteristics of aero‐allergenic pollen. Given the extent of current and future climate uncertainty, there is a need to strengthen predictive pollen forecasts. Methods: The study aims to use CatBoost (CB) and deep learning (DL) models for predicting the daily total pollen concentration up to 14 days in advance for 23 cities, covering all five continents. The model includes the projected environmental parameters, recent concentrations (1, 2 and 4 weeks), and the past environmental explanatory variables, and their future values. Results: The best pollen forecasts include Mexico City (R2(DL_7) ≈.7), and Santiago (R2(DL_7) ≈.8) for the 7th forecast day, respectively; while the weakest pollen forecasts are made for Brisbane (R2(DL_7) ≈.4) and Seoul (R2(DL_7) ≈.1) for the 7th forecast day. The global order of the five most important environmental variables in determining the daily total pollen concentrations is, in decreasing order: the past daily total pollen concentration, future 2 m temperature, past 2 m temperature, past soil temperature in 28–100 cm depth, and past soil temperature in 0–7 cm depth. City‐related clusters of the most similar distribution of feature importance values of the environmental variables only slightly change on consecutive forecast days for Caxias do Sul, Cape Town, Brisbane, and Mexico City, while they often change for Sydney, Santiago, and Busan. Conclusions: This new knowledge of the ecological relationships of the most remarkable variables importance for pollen forecast models according to clusters, cities and forecast days is important for developing and improving the accuracy of airborne pollen forecasts. [ABSTRACT FROM AUTHOR]

This paper explores the influence of two thermal loading protocols on the evolutions of stress state and soil consolidation characteristics during subsequent mechanical loading. We employed a specially designed thermal consolidometer to conduct a series of drained heating tests with temperature gradient across a saturated kaolin specimen at different levels of vertical effective stress. The thermal consolidometer accommodated for (1) continuous measurements of excess pore water pressure and temperature at different locations within a specimen; and (2) establishment of a steady nonuniform soil temperature distribution, a condition that often exists in the field. Staged and cyclic thermal loading revealed the influences of vertical effective stress on total and nonrecoverable thermal strain. Continuous measurements of pore pressure and soil volume change traced the evolution of average vertical effective stress with void ratio. While the negative pore pressure measurements at the end of thermal consolidation of normally consolidated clay suggested a pseudo-overconsolidated behavior upon heating at low values of vertical effectives stress, such a tendency diminished with an increase in stress level. A gradual shift in normal consolidation line at ambient temperature suggested continuous hardening of a normally consolidated specimen when subjected to repeated thermal loading cycles in the past. [ABSTRACT FROM AUTHOR]

AbstractArrowleaf sida (Sida rhombifolia L.) is a weed that has a fibrous stem, aggressive root system and waxy leaves that can hinder herbicide absorption. Based on knowledge of the environmental requirements for germination of this species, it is possible to predict emergence to assist in integrated management. The aim of this investigation was to characterize the air temperature and soil water potential requirements for arrowleaf sida germination, to model the emergence in the field using thermal and hydrothermal time models and to evaluate the longevity of the arrowleaf sida seed bank. Laboratory experiments were conducted to determine the temperature and water potential for seed germination by testing eight temperatures (10, 15, 20, 25, 30, 35, 40, and 45 °C) and 10 water potentials (0, −0.05, −0.1, −0.2, −0.4, −0.6, −0.9, −1.2, −1.5, and −2.0 MPa). Field experiments were conducted between 2014 and 2018 to model the emergence using three sampling times (starting on 10/20, 11/10, and 12/01), during which soybean seeds were sown. To evaluate the longevity and persistence of the seed bank, a factorial experiment was conducted, in which the first factor included three burial depths (0, 3, and 6 cm) and the second factor included five collection times (0, 1, 4, 10, and 16 months) after seed burial. The base, optimal and maximum temperatures for arrowleaf sida germination were 10.0, 24.8, and 42.5 °C, respectively, and the base water potential was −1.20 MPa. It is possible to predict the emergence of arrowleaf sida in the field by hydrothermal and thermal time models under different environmental conditions. In addition, this species has a persistent seed bank, with 30% of seeds being viable after 16 months of burial. [ABSTRACT FROM AUTHOR]

We analyzed long-term soil CO2 concentrations, soil temperature and moisture, with simultaneous canopy microclimate measurements, in a subtropical 20 years old oak forest in Huainan, China, in the East Asian monsoon region. Daily soil CO2 effluxes were quantified using the gradient method. We investigated the relationship between soil CO2 concentrations and efflux, and both soil temperature and water content, and the effects of phenological stages and seasons. explored how abiotic factors (soil temperature and moisture) along with LAI influence soil CO2 efflux. Subsurface soil CO2 concentration and efflux showed clear seasonal variations, with an increase in spring to a small peak, reaching a maximum in summer, then a decrease in autumn but with a sharp second peak when precipitation season began, and finally a decrease to a minimum in winter. In this forest ecosystem, the calculated soil subsurface CO2 efflux at 0.02 m averaged 1.40 µmol m−2 s−1 and ranged from 0.24 to 4.11 µmol m−2 s−1 over a whole year from September 1, 2018 to August 31, 2019. Seasonal fluctuations in soil CO2 concentrations and efflux were primarily influenced by soil temperature, with soil moisture exerting secondary effects throughout the entire study period and in most cases. However, during warm, dry periods like summer or maturity stages, soil water content emerged as the primary factor governing CO2 efflux. The combined influences of soil temperature and water content were different in different phenological stages, and highly regulated by drought and rains. For instance, in the phenological mature stage, soil CO2 concentration was mainly affected by soil water content. In the mature stage, soil CO2 efflux correlated more closely with soil water content than with soil temperature following a spring drought episode. [ABSTRACT FROM AUTHOR]

Floral nectar is mainly a reward in the form of food for pollinators. In early spring, when snow can still be present, pollinators have trouble finding food. The composition and productivity of nectar in flowers play an important role in a pollinator's life. It is known that low temperatures and lower humidity cause lower nectar secretion. Some studies have also shown that the quality of nectar can differ because of lower temperatures. In our research, we analysed whether abiotic factors affect nectar secretion, as well as the nectar composition of the early spring plant species Galanthus nivalis L. and Helleborus niger L. in February 2024. The study was conducted in two locations in nature. Nectar from H. niger was sampled in Tomišelj, Slovenia, whereas nectar from G. nivalis was sampled in Ljubljana, Slovenia. On four different days at three different times of day, we sampled nectar from flowers using microcapillaries. In total, we sampled 48 nectar samples from one species. We analysed soil humidity and temperature, air temperature and humidity, and UVB radiation. Our results show that nectar productivity is highest in the morning for both species. H. niger has sucrose-dominant nectar, while G. nivalis has hexose-dominant nectar. Proline, which is an important amino acid for bees, has the highest level in both species, as does the phenolic compound rutin. Environmental factors do affect nectar secretion. Soil and air temperature affect G. nivalis nectar secretion, while soil humidity affects H. niger nectar secretion. Soil and air temperature also have an effect on higher levels of sugars in both researched nectars. UVB, air humidity, and air and soil temperature seem to have an effect on phenolic compounds, but abiotic factors do not affect amino acids. [ABSTRACT FROM AUTHOR]

Background: Food and nutritional security remain a major thrust area in the under developed and developing countries. These problems are exaggerated by the unprecedented challenges of climate change. Aims: The aim of this study was to assess the impact of climate change on grain quality of wheat and rice genotypes as well as their effect on soil aggregate fractions and aggregate associated carbon. Methodology: In the context, the present study was formulated by considering four predicted climate scenarios, namely, T0C0 (ambient condition), T0C1 (approx. 25% higher CO2), T1C0 (2°C higher temperature) and T1C1 (25% higher CO2 + 2°C higher temperature) and their impact on grain quality of wheat (HD2967, HD2733, DBW17, and HD3093) and rice (IR83376‐B‐B‐24‐2, IR84895‐B‐127‐CRA‐5‐1‐1, R Bhagwati, and IR64) genotypes as well as soil aggregate fractions and aggregate associated carbon. Results: The result revealed that T0C1 has a negative impact on grain nitrogen and protein content. On an average, nitrogen content in wheat and rice showed a decrease of about 15.55% (5.52%–25.32%) and 11.44% (3.33%–23.86%), respectively. Interestingly, the concurrent effect of elevated CO2 and temperature resulted in higher nitrogen and protein content as compared to other climate conditions. Further, P (P) content in the wheat and rice grains also improved under the elevated CO2 condition, whereas the content of potassium was not significantly influenced. Apart from major nutrients, micronutrients (Zn and Fe) were significantly influenced by climatic variables. The study revealed that grain Zn and Fe content of both the crops were reduced due to elevated CO2. The data on soil aggregate fractions revealed that elevated CO2 favors the formation of macro‐aggregate, whereas an increase in temperature favors micro‐aggregate fractions in the soil. Further, the elevation of CO2 also resulted in the accumulation of more carbon in the macro‐aggregates. Conclusion: We conclude that elevated CO2 and temperature cause specific changes in soil aggregate formation and grain nutrient quality. Based on molar ratio of P/Zn and P/Fe, we identified varieties of rice (IR83376‐B‐B‐24‐2) and wheat (HD2733) with higher bioavailability to address the nutritional security with changing climate in developing countries. [ABSTRACT FROM AUTHOR]

The matric suction of saline soil is the driving force that causes water migration, and it is of great significance for exploring the mechanism of water and salt migration in saline frozen soil. In order to investigate the effect of phase transition of soil pore solution induced by temperature on the matric suction of saline soil, the matric suction of different types of saline soils was measured by pF meter under different temperature conditions. The natural soil was first washed to obtain the desalinized soil, then different salt mass ratios of sodium chloride and sodium sulfate (0:6, 4:2, 2:4, 6:0) were added into the desalinized soil to model the composite saline soil, the salt content and water content were set to 6% and 20%, respectively. Subsequently, the remolded saline soil was compacted into the test chamber (0.37 m×0.25 m×0.22 m), and its dry density was controlled at 1.6 g/cm³. Hydra Probe II and pF meter were embedded at 11cm of the sample to measure the liquid water content and matric suction versus temperature. Freezing-thawing box (TMS 9 018-R30), produced by Zhejiang Tomos company, was employed to control the experimental temperature by step cooling method. The temperature range was from 30 to -24 °C, and the temperature interval was 3 °C. The data was collected by CR300 at an interval of 6 h. When the experiment was complete, the temperature effect of saline soil matric suction was analyzed and the effect of water/salt phase transition was explored. The experimental results reveal that the matric suction of saline soil increases almost linearly with the decrease of temperature when no phase transition occurs, which is caused by surface tension and wetting coefficient. Different types of saline soils have different effects on the phase transition process of pore solution, resulting in significant differences in the matric suction of different types of saline soils. The mirabilite crystallizes at 19 °C and the second phase transition occurs at -9 °C for the composite saline soil with 2% NaCl+4% Na2SO4, and the phase transition of composite saline soil with 4% NaCl+2% Na2SO4 occurs at 11 and -16 °C.Sodium chloride can inhibit the occurrence of ice formation, then the matric suction caused by ice formation is reduced, and the segregated frost heave caused by water migration is restrained indirectly. Besides, sodium sulfate is prone to crystallization at positive temperatures, and ice is also produced in the secondary phase transition process, both salt crystallization and ice formation increase the matric suction in sodium sulfate soil, and water and salt redistribute in this process, salt expansion and frost heave are induced. For composite saline soil, sodium sulfate mainly affects the salt crystallization of the soil at a positive temperature, while sodium chloride mainly affects the ice formation of the soil at a negative temperature. The different proportions of the two salts cause significant differences in the salt crystallization temperature and the secondary phase transition temperature, resulting in more complex phase transition laws in composite saline soil, and it is more difficult to predict the matric suction of composite saline soil. In addition, this paper further explores the contribution of ice and salt crystallization to the variation of matric suction, providing effective references for a deeper understanding of the relationship between phase transition processes and matric suction in saline soils. [ABSTRACT FROM AUTHOR]

Innovative practices like combining agroforestry with organic mulch can store carbon and enhance crop yields by regulating soil temperature, improving soil health and moisture. A study was conducted during 2022–23 in the mid-hills of the North-western Himalayas to evaluate the productivity of turmeric plants grown under different densities of Melia composita Willd. The research employed a split-plot design, utilizing different tree spacings (main plot)—8m × 5m (S1) and 8m × 4m (S2) of Melia composita trees and sole cropping, along with one control (T1) and nine distinct mulch treatments (sub-plots): T2 (Farm yard manure (FYM)), T3 (Toona ciliata + FYM + Recommended dose of fertilizer (RDF)), T4 (Artemis vulgaris + FYM + RDF), T5 (Ulmus villosa + FYM + RDF), T6 (Celtis australis + FYM + RDF), T7 (Pinus roxburghii + FYM + RDF), T8 (Pistacia integrimma + FYM + RDF), T9 (Phyllostachys aurea + FYM + RDF), T10 (Melia composita + FYM + RDF). The results showed that higher biomass (301.54 Mg ha−1) and carbon density (143.24 Mg ha−1) were achieved with S2 tree spacing than S1. However, for better turmeric growth and yield, S1 tree spacing performed better. Among the different mulch treatments, T6 produced the highest curcumin percentage, primary finger count, and mother rhizome weight. On the other hand, T10 resulted in the highest primary finger weight and total yield. Using T3 mulch enhanced the level of available N, P, K in soil and mulch used in T9 improved the soil microbial characteristics. Turmeric intercropped with M. composita in 8m × 5m (S1) and 8m × 4m (S2) spacing resulted in net returns of $7948.44 ha−1 and $7456.64 ha−1 year−1, respectively, which were 23.74% and 16.07% increase compared to sole cropping (S3). This research provides valuable insights into optimizing tree spacing and mulch materials in an agroforestry system based on M. composita, which enhances turmeric crop productivity, soil health and economic viability. [ABSTRACT FROM AUTHOR]

Land suitability assessment is integral to the advancement of precision agriculture. This inquiry is focused on identifying optimal regions for cultivating Alphonso mango in the coastal belt of Maharashtra, spanning across Palghar, Raigad, Thane, Ratnagiri, and Sindhudurg districts. Employing a GIS-based Analytic Hierarchy Process (AHP) methodology, 10 crucial parameters have been considered, encompassing climatic, physical, and chemical soil characteristics: cation exchange capacity, organic carbon, slope, rainfall, soil pH, soil texture, mean annual soil temperature, base saturation, soil drainage, and soil depth. Weights are assigned to these parameters based on expert opinions and existing literature to determine their significance in developing a soil suitability map. The study reveals distinct land suitability zones for Alphonso mango cultivation. The land suitability map designates 25.78% of the study area as highly suitable, while 9.18% is considered unsuitable for Alphonso mango cultivation. To validate the study, the Receiver Operating Characteristic (ROC) curve has been employed, indicating an 83% approval rate for the reliability and performance of the soil suitability. The results categorise soil suitability classes, providing valuable insights for farmers and agricultural planners to make informed decisions regarding Alphonso mango cultivation in similar geoenvironmental regions. [ABSTRACT FROM AUTHOR]

Purpose: Land use changes influence soil porosity, soil water, and heat transport, which may alter freeze–thaw characteristics within the soil profile. However, the response to freeze–thaw process after long-term land use change in Northeast China is still unclear. Thus, this study explored the characteristics and dynamics of soil hydrothermal during the freeze–thaw process in Northeast China. Materials and methods: The investigation focused on grassland and bare land that have undergone a long-term transformation from cropland. The soil temperature (ST) and soil water content (SWC) data during the freeze–thaw period were collected from 2016 to 2021. Characteristics of ST and SWC at 0–180 cm soil depth were carried out in two sites during the freeze–thaw period. Results: It was found that soil in the bare land started to freeze and thaw earlier than that in the grassland. The bare land exhibited a 10.3–186.2% higher amplitude in ST at different depths and greater thermal efficiency between air and soil. In both study sites, the SWC showed a downward–stable–upward trend at different soil layers during the monitoring period. The migrated SWC in most soil layers decreased in two sites. The maximum amount of migrated water reached 2.11 and 5.14 mm in grassland and bare land, respectively. The SWC correlated exponentially with absolute temperature in two sites but decreased faster at 0–30 cm depths in the same temperature interval in bare land. Conclusions: The soil in the grassland had more stable water and heat regulation ability than that in the bare land. Our results contribute to improving the comprehension of the relationship between water and heat in different land uses in seasonal frozen regions. [ABSTRACT FROM AUTHOR]

Data on the soil nutrient content are required to calculate fertilizer rate recommendations. The soil laboratory determines these soil properties, yet the measurement is time-consuming and costly. Meanwhile, portable devices to assess the soil nutrient content in real-time are limited. However, a proprietary and low-cost NPK sensor is available and commonly used in IoT for agriculture. This study aimed to assemble and test a portable, NPK sensor-based device in irrigated and rainfed paddy soils from Java, Indonesia. The device development followed a prototyping approach. The device building included market surveys and opted for an inexpensive, light, and compact soil sensor, power storage, monitor, and wire connectors. Arduino programming language was used to write scripts for data display and sub-device communication. The result is a real-time, portable soil nutrient detector that measures the soil temperature, moisture, pH, electrical conductivity, and N, P, and K contents. Field tests show that the device is sensitive to soil properties and location. The portable soil nutrient detector may be an alternative tool for the real-time measurement of soil nutrients in paddy fields in Indonesia. [ABSTRACT FROM AUTHOR]

The temperature sensitivity (Q10) of soil respiration (Rs) plays a crucial role in evaluating the carbon budget of terrestrial ecosystems under global warming. However, the variability in Q10 along soil moisture gradients remains a subject of debate, and the associated underlying causes are poorly understood. This study aims to investigate the characteristics of Q10 changes along soil moisture gradients throughout the whole growing season and to assess the factors influencing Q10 variability. Changes in soil respiration (measured by the dynamic chamber method) and soil properties were analyzed in a poplar plantation located in the suburban area of Beijing, China. The results were as follows: (1) Q10 increased with the increasing soil water content up to a certain threshold, and then decreased, (2) the threshold was 75% to 80% of the field capacity (i.e., the moisture content at capillary rupture) rather than the field water-holding capacity, and (3) the dominant influence shifted from soil solid-phase properties to microbes with increasing soil moisture. Our results are important for understanding the relationship between the temperature sensitivity of soil respiration and soil moisture in sandy soil, and for the refinement of the modeling of carbon cycling in terrestrial ecosystems. [ABSTRACT FROM AUTHOR]

Global warming leads to the melting of permafrost, affects changes in soil microbial community structures and related functions, and contributes to the soil carbon cycle in permafrost areas. Located at the southern edge of Eurasia's permafrost region, the Greater Khingan Mountains are very sensitive to climate change. Therefore, by analyzing the bacterial community structure, diversity characteristics, and driving factors of soil profiles (active surface layer, active deep layer, transition layer, and permafrost layer) in this discontinuous permafrost region, this research provides support for the study of the carbon cycling process in permafrost regions. The results show that the microbial diversity (Shannon index (4.81)) was the highest at 0–20 cm, and the Shannon index of the surface soil of the active layer was significantly higher than that of the other soil layers. Acidobacteria and Proteobacteria were the dominant bacteria in the active layer soil of the permafrost area, and Chloroflexi, Actinobacteria, and Firmicutes were the dominant bacteria in the permafrost layer. Chloroflexi made the greatest contribution to the bacterial community in the permafrost soil, and Bacteroidota made the greatest contribution to the bacterial community in the active surface soil. The structure, richness, and diversity of the soil bacterial community significantly differed between the active layer and the permafrost layer. The number of bacterial species was the highest in the active layer surface soil and the active layer bottom soil. The difference in the structure of the bacterial community in the permafrost soil was mainly caused by changes in electrical conductivity and soil–water content, while that in the active layer soil was mainly affected by pH and soil nutrient indices. Soil temperature, NO3−-N, and pH had significant effects on the structure of the bacterial community. The active layer and permafrost soils were susceptible to environmental information processing and genetic information processing. Infectious disease: the number of bacterial species was significantly higher in the surface and permafrost layers than in the other layers of the soil. In conclusion, changes in the microbial community structure in soil profiles in discontinuous permafrost areas sensitive to climate change are the key to soil carbon cycle research. [ABSTRACT FROM AUTHOR]

Canopy gaps can result in abiotic heterogeneities and diverse niches from gap borders to centers, potentially affecting fine root decompositions mediated by soil fungal communities. Despite extensive discussions on the relationship between soil fungi and fine root decomposition, the mechanism by which gap locations regulate fine root decomposition through the soil fungal community remains elusive. Here, we conducted an in situ field decomposition experiment of Chinese Toon (Toona sinensis) fine roots in a low-efficiency weeping cypress (Cupressus funebris) plantation forest across three microhabitats: gap centers, gap borders, and closed canopy areas. Soil fungal communities were determined using internal transcribed spacer (ITS) sequencing after two years of field incubation. Results showed that soil properties and nutrient content in residual roots varied across the three microhabitats, with the gap borders exhibiting the highest decomposition rates. While fungal α-diversity remained relatively consistent, taxonomic compositions differed significantly. Decomposition rates did not show significant correlations with soil properties, observed fungal ASVs, or overall community composition. However, they positively correlated with the relative abundance of saprotrophic Sordariomycetes, which in turn positively correlated with soil total nitrogen (with a highest correlation), peaking at the gap borders. Overall community variations were primarily driven by soil temperature and magnesium content in residual roots. Further analysis revealed high fungal community similarities and low dispersal limitations between the gap borders and closed canopy areas, with more phylogenetically clustered communities at the borders. These results demonstrate that the gap borders possess a high decomposition rate, likely due to the centralization of functions driven by soil fungi such as saprotrophs existing in the "microbial seed bank" or migrating from closed canopy areas. These findings highlight the key role of soil fungi, especially saprotrophic fungi, in fine root decomposition at the gap borders, stressing the importance of soil fungi-driven mechanisms in nutrient cycling, and also informing sustainable forest management practices. [ABSTRACT FROM AUTHOR]

With global warming, forests are increasingly exposed to "compound soil and atmospheric drought" (CSAD) events, characterized by low soil water content (SWC) and high vapour pressure deficit (VPD). Such CSAD events trigger responses in both ecosystem and forest-floor CO2 fluxes, which we know little about. In this study, we used multi-year daily and daytime above-canopy (18 years; 2005–2022) and daily forest-floor (5 years; 2018–2022) eddy covariance CO2 fluxes from a Swiss forest site by the name of CH-Lae (a mixed deciduous montane forest). The objectives were (1) to characterize CSAD events at CH-Lae, (2) to quantify the impact of CSAD events on ecosystem and forest-floor CO2 fluxes, and (3) to identify the major drivers and their temporal contributions to changing ecosystem and forest-floor CO2 fluxes during CSAD events and CSAD growing seasons. Our results showed that the growing seasons of 2015, 2018, and 2022 were the three driest at CH-Lae since 2005 (referred to as the CSAD years), exhibiting similar intensity and duration of the CSAD events but considerably different pre-drought conditions. The CSAD events reduced daily mean net ecosystem productivity (NEP) in all 3 CSAD years by about 38 % compared to the long-term mean, with the highest reduction observed during 2022 (41 %). This reduction in daily mean NEP was largely due to decreased gross primary productivity (GPP; > 16 % below the long-term mean) rather than increased ecosystem respiration (Reco) during CSAD events. Furthermore, forest-floor respiration (Rff) decreased during the CSAD events in 2018 and 2022 (with no measurements in 2015), with a larger reduction in 2022 (41 %) than in 2018 (16 %), relative to the long-term mean (2019–2021). Using data-driven machine learning methods, we identified the major drivers of NEP and Rff during CSAD events. While daytime mean NEP (NEPDT) during the 2015 and 2018 CSAD events was limited by VPD and SWC, respectively, NEPDT during the 2022 CSAD event was strongly limited by both SWC and VPD. Air temperature had negative effects, while net radiation showed positive effects on NEPDT during all CSAD events. Daily mean Rff during the 2018 CSAD event was driven by soil temperature and SWC but was severely limited by SWC during the 2022 CSAD event. We found that a multi-layer analysis of CO2 fluxes in forests is necessary to better understand forest responses to CSAD events, particularly if the first signs of NEP acclimation to CSAD events – evident in our forest – are also found elsewhere. We conclude that CSAD events have multiple drivers with different temporal contributions, making predictions about site-specific CSAD events and long-term forest responses to such conditions more challenging. [ABSTRACT FROM AUTHOR]

In the process of agricultural production in solar greenhouses, the key to the healthy growth of greenhouse crops lies in accurately predicting environmental conditions. However, there are complex couplings and nonlinear relationships among greenhouse environmental parameters. This study independently developed a greenhouse environmental acquisition system to achieve a comprehensive method for the monitoring of the greenhouse environment. Additionally, it proposed a multi-parameter and multi-node environmental prediction model for solar greenhouses based on the Golden Jackal Optimization-Convolutional Neural Network-Bidirectional Gated Recurrent Unit-Self-Attention Mechanism (GCBS). The GCBS model successfully captures the complex nonlinear relationships in the greenhouse environment and accurately predicts changes in carbon dioxide concentration, air temperature and humidity, and soil temperature at different location nodes. To validate the performance of this model, we employed multiple evaluation metrics and conducted a comparative analysis with four baseline models. The results indicate that, while the GCBS model exhibits slightly higher computational time compared to the traditional Long Short-Term Memory (LSTM) network for time series prediction, it significantly outperforms the LSTM in terms of prediction accuracy for four key parameters, achieving improvements of 76.89%, 69.37%, 59.83%, and 56.72%, respectively, as measured by the Mean Absolute Error (MAE) metric. [ABSTRACT FROM AUTHOR]

Color change is the most obvious characteristic of the tomato ripening stage and an important indicator of the tomato ripening condition, which directly affects the commodity value of tomato. To visualize the color change of tomato fruit during the mature stage, this paper proposes a gated recurrent unit network with an encoder–decoder structure. This structure dynamically simulates the growth and development of tomatoes using time-dependent lines, incorporating real-time information such as tomato color and shape. Firstly, the.json file was converted into a mask.png file, the tomato mask was extracted, and the tomato was separated from the complex background environment, thus successfully constructing the tomato growth and development dataset. The experimental results showed that for the gated recurrent unit network with the encoder–decoder structure proposed, when the hidden layer number was 1 and hidden layer number was 512, a high consistency and similarity between the model predicted image sequence and the actual growth and development image sequence was realized, and the structural similarity index measure was 0.746. It was proved that when the average temperature was 24.93 °C, the average soil temperature was 24.06 °C, and the average light intensity was 11.26 Klux, the environment was the most suitable for tomato growth. The environmental data-driven tomato growth model was constructed to explore the growth status of tomato under different environmental conditions, and thus, to understand the growth status of tomato in time. This study provides a theoretical foundation for determining the optimal greenhouse environmental conditions to achieve tomato maturity and it offers recommendations for investigating the growth cycle of tomatoes, as well as technical assistance for standardized cultivation in solar greenhouses. [ABSTRACT FROM AUTHOR]

Soil temperature regulates biogeochemical processes and is a key environmental factor affecting salt marsh ecosystems. Previous studies on soil temperature and heat transport in intertidal marshes predominantly focused on short‐term changes, leaving seasonal variations unclear. This study conducted a yearlong field and modeling investigation to examine temporal and spatial temperature variations in a creek‐marsh section under estuarine and meteorological influences. The results showed that inundating tidal water propagated the seasonal water temperature signal to marsh soils, especially at low elevations, thereby modulating air temperature‐induced soil temperature variations and distributions. The response of soil temperature to air and tidal water temperatures exhibited a damped and delayed pattern. In contrast, tide‐induced porewater circulations near the creek facilitated the temperature responses. A regression model incorporating a Gamma distribution function was developed to quantify the delayed and cumulative thermal effects of tidal water and air on shallow soil temperatures. The model coefficients varied along the creek‐marsh section, capturing the seasonal regulation of periodic tidal inundation on soil temperature in the low‐elevation marsh and near the creek. Sensitivity analyses indicated that relative sea level rise lowered yearly‐averaged temperatures for the marsh platform by enhancing latent heat export. Surface water warming increased the marsh temperatures at lower elevations. This study demonstrates that the creek‐marsh topography, warming, and relative sea level rise jointly affect soil temperature dynamics, advancing our understanding of temperature‐dependent biogeochemical processes in marsh ecosystems. Key Points: Seasonal temperature distributions along a creek‐marsh section were identifiedShallow soil temperature dynamics were predominated by seasonal tidal water and air temperaturesRelative sea level rise decreased the yearly‐averaged temperature in the high‐elevation marsh [ABSTRACT FROM AUTHOR]

This study assesses snow water equivalent (SWE) simulation uncertainty in the National Water Model (NWM) due to forcing and model parameterization, using data from 46 Snow Telemetry (SNOTEL) sites in the Upper Colorado River Basin (UCRB). We evaluated the newly developed Analysis of Record for Calibration (AORC) forcing data for SWE simulation and examined the impact of bias correction applied to AORC precipitation and temperature. Additionally, we investigated the sensitivity of SWE simulations to choices of physical parameterization schemes through 72 ensemble experiments. Results showed that NWM driven by AORC forcings captured the overall temporal variation of SWE but underestimated its amount. Adjusting AORC precipitation with SNOTEL observations reduced SWE root‐mean‐square error (RMSE) by 66%, adjusting temperature trimmed it by 10%, and adjusting both decreased it by 69%. Among the physical processes, the snow/soil temperature time scheme (STC) demonstrated the highest sensitivity, followed by the surface exchange coefficient for heat (SFC), snow surface albedo (ALB), and rainfall and snowfall partitioning (SNF), while the lower boundary of soil temperature (TBOT) proved to be insensitive. Further optimization of the parameterization combination resulted in a 12% SWE RMSE reduction. When combined with the bias‐corrected AORC precipitation and temperature, this optimization led to a remarkable 78% SWE RMSE reduction. Despite these enhancements, a persistent slow and late spring ablation suggests model deficiencies in snow ablation physics. The study emphasizes the critical need to enhance the accuracy of forcing data in mountainous regions and address model parameterization uncertainty through optimization efforts. Plain Language Summary: This study examines how accurately the National Water Model (NWM) predicts the amount of snow water equivalent (SWE) in the Upper Colorado River Basin (UCRB). Using data from 46 monitoring sites, we looked at how different factors affect the model's accuracy. We found that while the NWM can show changes in SWE over time, it consistently underestimates the actual amount when using certain forcing data. Adjusting this data with observations improved the model's accuracy significantly. We also identified specific model settings that strongly influence the results. Although optimizing these settings only improved accuracy by a small amount, combining them with adjusted forcing data led to a significant improvement. Despite these improvements, the model still struggles to predict late spring snowmelt accurately. This study emphasizes the importance of using accurate data and model settings for managing water resources effectively in mountainous areas. Key Points: National Water Model driven by Analysis of Record for Calibration (AORC) captures SWE temporal variation but underestimates its amountAdjusting precipitation reduces SWE RMSE by 66%, adjusting temperature reduces it by 10%, and adjusting both reduces it by 69%Parameterization optimization reduces SWE RMSE by 12%, while it leads to a 78% reduction when combined with adjusted AORC [ABSTRACT FROM AUTHOR]

Copyright of Journal of Soil & Water Conservation (1009-2242) is the property of Institute of Soil & Water Conservation and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Soil & Water Conservation (1009-2242) is the property of Institute of Soil & Water Conservation and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Background Aims Methods Results Conclusions The current transformation of the entire energy system leads to a large‐scale expansion of extra‐high‐voltage underground transmission lines (UTL). Knowledge of the impact on soil temperature and soil moisture dynamics is fundamental for environmental evaluation.We investigated the impact of an existing 320 kV underground cable in continuous operation on soil temperature and moisture dynamics.A soil‐monitoring programme was established at four study sites in Western Germany. Data were continuously recorded in soil up to 120 cm depth using soil sensors over a period of 1 year.Soil warming was in a range of 0.6 K in the topsoil, approx. 1–1.3 K in the rooting zone and 1.7 K in the subsoil at 120 cm depth and was restricted mainly to the immediate vicinity of the cable route. Likewise, the impact on soil moisture dynamics was on average in a range of −1.00 wt.‐% in 0–60 cm depth and −2.45 wt. 2‐% in the subsoil relative to control. Although at a calculated maximum load capacity of 100% in regular operation, soil warming might remain moderate, with 1.5 K in the topsoil, 2.3–3.1 K in the rooting zone and 4.1 K in the subsoil.It is assumed that the reasons for the low‐to‐moderate influence of the UTL are to be found in the operational cable load (on average 65%), heat loss of cables (approx. 12 W m−1 per cable) and the quality of the imbedding material for the cables. [ABSTRACT FROM AUTHOR]