Semi-arid Climatic Regions Research Articles

Distribution and prediction of biocrusts under the canopy of typical vascular plants on the Loess Plateau, Northwest China.

Vascular plants exert significant effects on micro-environment, thereby affecting the distribution of biological soil crusts (biocrusts). The relationship between vascular plants and the spatial distribution characteristics of biocrusts is largely unknown. We investigated the distribution characteristics of biocrusts under the canopy of vascular plants in the water-wind erosion crisscross area of the Loess Plateau, where larger areas of biocrusts had been formed since the implantation of "Grain for Green" project. We analyzed the relationship between the canopy characteristics of different vascular plants and the spatial distribution of biocrusts using correlation analysis and random forest importance ranking methods, and further constructed a predictive model for the area of biocrusts under the canopy of vascular plants. The results showed that: 1) Cyanobacteria crust was the predominant biocrusts, followed by moss crust. 2) The canopy of vascular plants affected the spatial distribution of biocrusts, with notable differences in distribution pattern across different directions under the canopy of vascular plants. Biocrusts were primarily distributed in the 270°-315° and 315°-360° directions, while was less frequent in the 90°-135° and 135°-180° directions. 3) Radially, the coverage of biocrusts gradually increased from the root-base to the edge of the canopy of vascular plants. 4) The coverage of biocrusts under canopy was significantly related to the characteristics of vascular plants, including canopy area, long crown width, short crown width, litter area and plant height. 5) The relative importance of canopy area, long crown width, and short crown width to the biocrusts under the canopy was 13.7%, 12.1%, and 11.9%, respectively, while the relative importance of plant height and species type was relatively low, being 6.7% and 4.4%, respectively. 6) Results of the random forest model demonstrated strong predictive performance for biocrusts distribution based on canopy characteristics of vascular plants, with a prediction accuracy of 0.59 (R2) and a root mean square error of 1.2 m2. This model could be applied to predict and estimate the area of biocrusts under the canopy of vascular plants. This study provided a theoretical basis for in-depth understanding of the relationship between vascular plants and biocrusts in semi-arid climate regions, as well as for predicting the spatial distribution of biocrusts.

Comparative Analysis of Aerosol Direct Radiative Forcing During COVID-19 Lockdown Period in Peninsular India

AbstractThe load of aerosols in the atmosphere has been increasing gradually due to industrialization and urbanization. This increase has contributed to change in the Earth’s radiation budget through the absorption or scattering of radiation. The aerosol direct radiative forcing (ADRF) is a measurement utilized to comprehend the impact of cooling or warming up of the atmosphere directly by aerosols. Our study examined the impact of aerosols during the COVID-19 pandemic by comparing them to the average from the preceding 5-year period (2015–2019) in peninsular India. The measure of aerosols deployed in this study is the Aerosol Optical Depth (AOD), and the study was carried out on three distinct time frames: prior to lockdown, during lockdown, and post lockdown. The study revealed that the ADRF increased during all the three time frames of 2020 compared to the average of 2015–2019, and the other time scales experienced an increase in ADRF as well. The most notable rise in ADRF and decrease in temperature occurred in the tropical savanna and warm semi-arid climate regions during the pre-lockdown period. During lockdown, the increase in ADRF was seen throughout the study area, and a decrease in temperature was observed only in the tropical monsoon region. In the post-lockdown period, the decline in ADRF was accompanied by a fall in temperature in the tropical savanna region. This study provides insights into the effect of aerosols on ADRF in peninsular India and highlights the importance of monitoring and regulating aerosol emissions to mitigate the changes in temperature.

A life cycle carbon dioxide equivalent emissions assessment of zero carbon building in hot semi-arid climate region: Case study

As societies are shifting toward carbon neutral environments, they are beginning to account for their carbon emissions. One of the primary contributors of greenhouse gas emissions and global warming is the building industry; therefore, Life Cycle Assessment (LCA) is one of the instruments that allows an assessment of the energy and the energy-related environmental impacts of the buildings from cradle to grave, according to ISO 14040. In this context, the aim of this research study is to assess the Life Cycle carbon dioxide (LC CO2eq) emissions over a 50-year-lifespan of a zero-carbon solar-powered earth-based building, built with carbon-free adobe bricks, in the hot semi-arid climate of Morocco. While research on the carbon dioxide equivalent (CO2eq) emissions across the life cycle is crucial to determine the energy-intensive stages, this study looks into global tendencies of CO2eq emissions arising during the cradle-to-gate embodied (A1-3) and operational (B6) phases of a Zero Carbon Building (ZCB) case study, and which should be offset by carbon-free energy in order to abide by the ZCB definition. Results show that the LC CO2eq emissions of the eco-friendly zero-carbon residential building falls in 48.62 Kg CO2eq/m2.y., with an operational phase that has a share of around 93 % of global LC CO2eq emissions. In addition, when conventional construction materials such as concrete, bricks, and insulation materials are used as an alternative, embodied carbon emissions accounts for 6.3 kg CO2eq/m2.y. and is 85 % higher than the eco-friendly building, and it constitutes approximately 12.5 % of the overall carbon footprint. Moreover, the annual embodied and operational CO2eq emissions are offset by the 3.3-kWc-building-added-photovoltaic system. Hence, the conducted case study offers valuable insight into the good practices for decarbonization of Morocco's building stock.Through that case study, we aim to generate knowledge of net zero carbon buildings within the African continent, promoting the perks of decentralized solar energy in leaping forward a carbon-free electrified continent and valorizing the local construction techniques and knowhow in the building sector.

Increasing effect of biocrusts on evaporation is evidenced by simulating evaporation and diffusion experiments and water stable isotope analysis

Evaporation, one of the main components of the water and energy balance between soil and atmosphere, plays a key role in hydrological processes particularly in semi-arid and arid climate regions. As critical living organism communities inhabiting the soil-atmosphere boundary, biocrusts are capable of modifying near-surface soil properties and structure in drylands. However, the roles of biocrusts in mediating soil evaporation still remain greatly controversial, and the literature yet lacks in a systematic assessment. In this study, evaporation experiments were conducted under simulated isothermal and non-isothermal conditions for bare soil and three types of biocrusts (cyanobacterial, moss, and their mixture) sampled from a semi-arid climate region of the Chinese Loess Plateau. During the evaporation, soil temperature and moisture were measured at depths 2, 5, 10, and 15 cm for those biocrusts and bare soil. Their water vapor diffusion process and stable isotopic composition were also analyzed in the laboratory. We found that the measured evaporation yielded 4.9%, 17.5%, and 31.6% higher average evaporation rate for cyanobacterial, cyano-moss, and moss crusts, respectively, when compared to the bare soil. In comparison to bare soil, all types of biocrusts markedly reduced the rate of temperature rise, prolonged the duration of wetting time, and delayed the formation of dry surface layer. The largest regulating effects on soil temperature and moisture were found in the moss crusts instead of cyanobacterial or cyano-moss crusts. The increasing evaporation in biocrusts was attributed to their higher fine particle content, lower bulk density, and greater water holding capacity. Moreover, the water vapor diffusion rate and diffusivity of biocrusts were 18.2% and 16.4% higher than those of bare soil, respectively, which is attributable to the increased total porosity and better soil structure. Additionally, the isotopic composition of soil water (0–50 cm) in bare soil and moss crusts was distributed below the local meteoric water line. The mean δ18O and δ2H in soil water gradually decreased with increasing soil depth, and the moss crusts were more isotopically enriched than bare soil. Based on the enhanced soil evaporation rate, improved vapor diffusivity, and enriched isotopic composition of biocrusts in contrast to bare soil, we conclude that biocrusts exacerbate vapor transport and evaporative loss, and consequently they are crucial surface cover in rebalancing surface ecohydrological and biochemical processes in global drylands. These findings improve our understanding of the complexity of dryland hydrology, and a full consideration should be given in future biocrust studies.

Mycological surveys reveal two new species of genus Lepiota (Agaricaceae) from the semi-arid climatic region of Punjab, Pakistan

Mycological surveys reveal two new species of genus Lepiota (Agaricaceae) from the semi-arid climatic region of Punjab, Pakistan

Effect of using hydrogel polymers on morphometric, forage production, and nutritional characteristics of cactus pear

The use of cactus pear has shown poor performance in some areas of semi-arid climate regions, as the species needs a wide gradient between temperatures during the day and night to develop, which does not occur in such zones. To lessen this negative occurrence, moisture availability provides better performance for the species, such as using hydrogel instead of irrigation. The objective of this study was to evaluate the effect of using hydrogel polymers on the production of cactus pear (Opuntia stricta cv. Mexican Elephant Ear). Three treatments with six replications were used, totalling 18 experimental units. The treatments were, (1) Conventional fertilization using fertilizer in granulated format; (2) Foliar fertilization with polymer using a dilution dose of 6 grams of polymer L-1 of water associated with the fertilizer in liquid form through the foliar route; (3) Foliar fertilization without polymer using only foliar fertilization in the same formulation as the treatment with polymer. There was no effect of fertilization strategy on plant height, cladode length, cladode width, cladode thickness, cladode area, and biomass. There was an effect of the fertilization strategy on dry matter, in which higher estimates were measured for conventional fertilization and foliar fertilization without polymer. On the other hand, foliar fertilization with polymer promoted increases of 13% in mineral matter and 42% in crude protein in relation to conventional fertilization. The fertilization strategy did not change the other chemical attributes of cactus pear. The use of the hydrogel did not influence the morphometric development of the Mexican Elephant Ear cultivar but promoted increments in the chemical composition.

Species diversity, behavior and visit rates to melon flowers (Cucumis melo l.) as a function of time and seasonality in a semi-arid climate region in Brazil

In this research we evaluated the phenology of melon flowering (Cucumis melo L.) and the diversity of floral visitors in geographical conditions of semi-arid climate in Northeast Brazil, during the wet and dry seasons. The floral phenology of the melon was evaluated by recording the number of flowers produced/plant/day from 30 plants, the insects that visited the flowers were recorded following three methods: visual counts, sweep collection and counting and identification, we observe and count the number of visits to flowers from 30 plants (n = 30) during the first 45 minutes of each hour. This study reports the diversity of melon pollinators in geographical conditions located in a semi-arid climate region, with specific seasonal fluctuations, which explains the behavior pattern found at work. The order Hymenoptera predominated among floral visitors, especially Apis melífera and Trigona spinipes. The flowering cycle was influenced by seasonality, with a longer duration in the dry season, the flowering and visiting peaks were higher during the hottest hours of the day, regardless of the season. There was a preference for visitation in the morning hours, with a peak at 10 a.m. and a gradual decrease in the presence of insects in the late afternoon.

Spatial assessment and chemical characterization of degraded (salt-affected) soils at post-reclamation stage of the Indo-Gangetic Plain in Haryana State.

Dynamics of soil salinity and sodicity is a common feature driven by anthropogenic causes such as soil reclamation, the effect of extreme climate events, disturbed salt, and water balance in irrigated areas that are devoid of any good quality groundwater source and adequate natural surface drainage condition in a semiarid climatic region. Periodic soil salinity assessment is therefore vital to know the current soil salinity status, plan reclamation, and/or management strategies for sustained agricultural growth and livelihood security. Temporal studies using Indian Remote Sensing (IRS) LISS III data, at pre- (1997) and post-reclamation (2017) stages have indicated spatial changes as reclaimed areas (~ 35%) and dynamics of soil salinity as increased areas (~ 61%) under irrigation across the Gangetic plain of Haryana State. The prominent areas of reclaimed sodic soil soils were located in the old alluvial plain which covered Panipat (12.32%), Karnal (6.01%), and Jind (5.9%) districts. Based on pH, ECe, and ESP values, these were classified as slight (Sso1, 8.75%), moderate (Sso2, 24.73%), and strong (Sso3, 18.20%) sodic soils, respectively. Significant salinity-inflictions (emerging areas) were identified at low-lying, poorly drained, irrigated soils in south and central Haryana that cover Jhajjar (13.99%), Sirsa (11.06%), Hisar (10.15%), Rohtak (8.73%), Bhiwani (6.43%), Palwal (4.31%), and Rewari (3.01%) districts. Slight (Ssa1, 16.82%), and moderate (Ssa2, 22.13%), categories are dominant soils, respectively. Among the landforms, significant areas (28.24%) were identified in the old alluvial plain with sand dunes (OAPSD), aeo-fluvial plain (AFP, 8.6%), and fluvio-aeolian plain (FAP, 6.0%), respectively. Dominant areas of reclaimed soils (14.4%) were identified in OAPSD. The soil analysis data indicated that these soil are moderate to strongly sodic (pH 8.7-11.0) and saline (ECe 4-26 dS m-1). The reclaimed sodic soils showed prominent improvement in soil pH and sodicity levels (pH 8.3-9.2) at 0-15cm depth and are commonly located in the Ghaggar and Yamuna river plains. Poor quality groundwater with high Residual Sodium Carbonate (RSC) was dominant at selected locations under the arid and semiarid climate. The database can also be used as a reference database for further monitoring of soil salinity status particularly in the irrigated regions. Currently, it is also used as a primary database for harmonization, monitoring, and reconciling of similar soils of the world under the Global Soil Partnership projects.

Tecnologias para redução do uso de água no abacaxizeiro em região semiárida

ABSTRACT: In irrigated systems, the adoption of management methods like soil cover, polymers which absorb the water present in the soil and the utilization of shading screens can decrease the water consumption by the plants. This is achieved as these means protect the plant and soil against radiation and wavelengths of light undesirable for cultivation. However, for pineapple cultivation in the semi-arid climate regions, very little study has been done regarding these technologies. Hence, the present study conducted to assess the pineapple growth, production and quality when various kinds of soil cover, red shading screen and water absorption polymers are employed. To accomplish this, a field trial was performed utilizing four types of soil cover in the plots (plastic mulching; organic matter; organic matter + red shading screen 50%; plastic mulching + red shading screen 50% and the control (no cover).Two treatments were included in the subplots namely, either the absence or presence of a water-absorbing polymer in the planting hole (0.5 g per plant), arranged in subdivided plots. We adopted the Randomized Complete Block (RCB) , with three replications. The following aspects of the plants were studied: naturally flowering, stem diameter; leaf area index; D-leaf area and total leaf area; fruit weight with crown; fruit weight without crown; fruit length with crown; and fruit length without crown, as well as the traits of the post-harvest fruit, soluble solids, titratable acidity, pH and the soluble solids/titratable acidity ratio. Further, the productivity in t ha-1 and efficiency of water use (EUA) were ascertained. It was evident that the plastic mulching + 50% red shading screen favored the vegetative development and productivity of the ‘IAC Fantástico’ pineapple plants. The characteristics of the quality of the postharvest fruit were unaffected by the treatments. The shading screen reduced the percentages of natural flowering in the treatments which included organic matter + red shading screen 50% and plastic mulching + red shading screen 50%.

Estimation of Water Surface Reflectance and Total Suspended Solid Using MODIS Images for a Reservoir in the Brazilian Semiarid Region

Reservoirs are essential sources to ensure water supply, especially in regions with a semiarid climate, prone to prolonged drought periods and water scarcity. An exemplary case is the semiarid region of Paraíba State, Brazil. Monitoring of water surface reflectance (WSR) and total suspended solids (TSS) is indispensable to address issues such as erosion, sediment transport, depo sition, reservoir siltation, water pollution, and associated human health risks, ultimately aiding in water resources management. This study introduced a novel approach to estimating the spatiotemporal dynamics of WSR and TSS, utilizing automated methods and MODIS images over 17 years (2000 ~ 2016) for the Epitácio Pessoa Reservoir. Three models, (a) model 1 (M1), (b) model 2 (M2), and (c) model 3 (M3), were employed to estimate WSR and TSS, chosen for their replicability, mathematical simplicity, and ecosystem similarity. A total of 775 images from the Moderate Resolution Imaging Spectroradiometer (MODIS) onboard the Terra satellite, along with observed data, were used for the estimation. Model M3 yielded the best performance for estimating TSS, with values ranging from 270 ~ 961 mg/L (r = 0.57). Furthermore, a strong correlation (r > 0.93) was observed between the mean reflectance values for pixels sampled using two distinct extraction procedures (longitudinal profile and specific sampling points). This strong correlation underscores the potential utility of MODIS images for effective monitoring of WSR and TSS in comparatively smaller bodies of water in the Brazilian semiarid region. Importantly, this study represents one of the first applications for estimating WSR and TSS for a reservoir situated in a semiarid climate region. The estimates of WSR and TSS could hold significant implications for environmental monitoring and water management of such reservoirs. In conclusion, automated estimation of WSR and TSS could serve as a valuable tool for decision-makers in predicting silting, sediment yield, and reservoir water quality.

Dairy cattle and buffaloes harbouring gastrointestinal parasites in various zones and climatic regions established by scientometrics

The prevalence of gastrointestinal parasites (GIP) in cattle and buffaloes from different zones and climatic regions in India was determined by scientometrics. The GIP prevalence studies (64) described during 2004–2021 were retrieved from online databases, and offline literature and meta-analyses were conducted by meta package in R-Software. The GIP prevalence in India was 47% (95% level CI 41–54%, PI 12–85%) in cattle, 42% (95% level CI 35–50%, PI 9–84%) in buffaloes and 45% (95% level CI 40–51%, PI 12–84%) in cattle and buffaloes obtained from 40,884, 27,624 and 74,579 samples, respectively. The GIP prevalence was higher in the South zone (60%) for cattle, North zone (52%) for both buffaloes, and cattle and buffaloes. A higher GIP prevalence was observed in Tamil Nadu for cattle, Chhattisgarh and Tamil Nadu for buffaloes, and Karnataka for cattle and buffaloes. Prevalence of Ostertagia spp. in cattle, Buxtonella spp. in buffaloes, and Haemonchus spp. in cattle and buffaloes were higher among parasitic species. The polar and Semi-Arid Steppe climatic region harbours more GIP than other regions. Thus, the higher prevalence zones, states, sample types, parasite classes, parasitic species, and climatic regions identified in the present study may be used by policymakers for making informed decisions and effectively using scarce resources. However, there is a need to prevent GIP infections by implementing scientific managemental practices in dairy farms, rotational use of anthelmintic drugs, appropriate control, and preventive measures, which will result in beneficial dairy farming in India.

Quantifying Drought Characteristics in Complex Climate and Scarce Data Regions of Afghanistan

Droughts cause critical and major risk to ecosystems, agriculture, and social life. While attempts have been made globally to understand drought characteristics, data scarcity in developing countries often challenges detailed analysis, including climatic, environmental, and social aspects. Therefore, this study developed a framework to investigate regional drought analysis (RDA) using regional drought intensity-duration-frequency (RD-IDF) curves and regional drought risk assessment (RDRA) based on the drought hazard indicator (DHI) and drought vulnerability indicator (DVI) for scarce data regions in Afghanistan. The drought characteristics were analyzed using the regional standardized-precipitation-index (SPI), and standardized precipitation-deficit distribution (SPDD). Further, L-moment statistics were used to classify different homogenous regions based on regional frequency analysis (RFA). The historical monthly precipitation data from 23 rainfall stations for the years 1970 to 2016 were collected from the Ministry of Water and Energy of Afghanistan. Based on the analysis performed, the area was classified into six homogeneous regions R-1, R-2, R-3, R-4, R-5, and R-6. The drought was very consistent—almost 50% of the years—irrespective of the homogeneous region classified. R-4, located in the northeast of the country, had a one-year extreme drought with high resiliency and low risk to drought compared to other regions. As R-1, R-3 and R-5 are located in the southwest, center and southeast parts of Afghanistan, they experience moderate drought with low resiliency and high drought risk due to long period of droughts. Moreover, the uniform distribution of precipitation deficit (Dm), was less in arid climate regions. In contrast, the semi-arid climate regions showed higher values of Dm. Furthermore, in the results in all the regions, the IDF curves showed a high drought intensity with increasing drought return periods. In contrast, the intensity significantly decreased when the time scale increased, and fewer were enhanced within the increasing drought return period. However, the outcome of this study may contain essential information for end users to make spatially advanced planning for drought effect mitigation in Afghanistan.

RLNformer: A Rainfall Levels Nowcasting Model Based on Conv1D_Transformer for the Northern Xinjiang Area of China

Accurate precipitation forecasting is of great significance to social life and economic activities. Due to the influence of various factors such as topography, climate, and altitude, the precipitation in semi-arid and arid areas shows the characteristics of large fluctuation, short duration, and low probability of occurrence. Therefore, it is highly challenging to accurately predict precipitation in the northern Xinjiang area of China, which is located in the semi-arid and arid climate region. In this study, six meteorological stations in the northern Xinjiang area were selected as the research area. Due to the high volatility of rainfall in this area, the rainfall was divided into four levels, namely, “no rain”, “light rain”, “moderate rain”, and “heavy rain and above”, for rainfall level prediction. In order to improve the prediction performance, this study proposed a rainfall levels nowcasting model based on Conv1D_Transformer (RLNformer). Firstly, the maximum information coefficient (MIC) method was used for feature selection and sliding the data, that is, the data of the first 24 h were used to predict the rainfall levels in the next 3 h. Then, the Conv1D layer was used to replace the word-embedding layer of the transformer, enabling it to extract the relationships between features of time series data and allowing multi-head attention to better capture contextual information in the input sequence. Additionally, a normalization layer was placed before the multi-head attention layer to ensure that the input data had an appropriate scale and normalization, thereby reducing the sensitivity of the model to the distribution of input data and helping to improve model performance. To verify the effectiveness and generalization of the proposed model, the same experiments were conducted on the Indian public dataset, and seven models were selected as benchmark models. Compared with the benchmark models, RLNformer achieved the highest accuracy on both datasets, which were 96.41% and 88.95%, respectively. It also had higher accuracy in the prediction of each category, especially the minority category, which has certain reference significance and practical value.

Remote sensing delineation of wildfire spatial extents and post-fire recovery along a semi-arid climate gradient

Understanding the wildfire extent and post-fire vegetation recovery is critical for fire and forest management. Remote sensing imagery is widely used in wildfire detection because it provides continuous and large-scale surface monitoring capability. In this study, we apply and evaluate the performance of the LandTrendr algorithm in wildfire detection across a semi-arid climate region with a marked precipitation gradient. The aims are to compare the performance of four spectral indices for the burned areas and post-fire recovery detection for different climate conditions and investigate the relationship between suitable model parameters and climate conditions. The results show that NDVI outperforms other indices, including NBR, in burned area detection for drier areas (annual precipitation <400 mm). Disturbance signal-to-noise ratio can serve as an indicator for suitable index selection for semi-arid areas. Although the performance in the detection of burned pixels varies among different indices, they are all suitable for delineating post-fire recovery except for the wet site (annual precipitation of 575 mm) where NBR displays the best performance. Parameter optimization results along the climate gradient show that climate conditions have a significant impact on suitable parameter selection. These findings provide guidance on vegetation wildfire detection in arid and semi-arid climates to support wildfire risk and forestry management.

Application of empirical mode decomposition, particle swarm optimization, and support vector machine methods to predict stream flows.

Modeling stream flows is vital for water resource planning and flood and drought management. In this study, the performance of hybrid models constructed by combining least square support vector machines (LSSVM), empirical model decomposition (EMD), and particle swarm optimization (PSO) methods in modeling monthly streamflow was evaluated. For establishing the models, 42years of monthly average streamflow data was used in two hydrometer stations located in the Konya Closed Basin, covering 1964 to 2005. Lagged streamflow values ​​were selected as inputs according to partial autocorrelation values ​​in establishing the models. The dataset was divided into 70% training and 30% testing. Model performances were evaluated according to mean square error, root mean square error, correlation coefficients, scatter plot, and Taylor and Violin diagrams. As a result of the analysis, it was determined that the PSO-LSSVM and EMD-LSSVM models were slightly more successful than the single LSSVM model, and the best model was obtained with the EMD-PSO-LSSVM. In addition, in estimating monthly stream flows, 1-, 9-, 10-, 11-, and 12-month lagged streamflow values were the input combination that gave the best results in semi-arid climatic regions. This result demonstrated that EMD improved the performance of both LSSVM and PSO-LSSVM models by 1% to 5% based on correlation coefficient (R) values.

Effects of pipeline and well‐pad reclamation on topsoil properties: A meta‐analysis

AbstractThe development of horizontal drilling and hydraulic fracking has led to an increase in oil and natural gas extraction. Development of infrastructure to extract and transport these resources is expected to increase over the next few decades, resulting in extensive land disturbance. Although reclamation aims to sufficiently return disturbed lands to their pre‐disturbance use in an ecological sense, reclaimed rights‐of‐ways (ROW) commonly produce reduced crop yields. The objective of this study was to use meta‐analysis to determine soil disturbance trends across studies found in the peer‐reviewed literature. Papers that reported soil property data on disturbed ROWs and adjacent undisturbed sites were retrieved by searching the Web of Science database. Papers were separated by climate regions, resulting in analyses being conducted for studies in semiarid and humid climate regions. Results indicate that soil bulk density, soil organic matter, and pH are significantly increased on reclaimed ROWs. Soil metrics not incorporated in meta‐analysis due to insufficient observations or the possible presence of publication biases like a desire to publish significant results and poor study design (cation exchange capacity, calcium, phosphorus, magnesium, total nitrogen, electrical conductivity, sodium, sodium adsorption ratio, and texture) are assessed and discussed. Best management practices gleaned from studies incorporated into meta‐analysis are discussed to provide strategies to limit soil property disturbances.

Experimental analysis on thermophysical properties of clay found in geographical areas of India and their ability to cool water for semi-arid climate regions

The Thermo physical behaviour of soil is the fundamental behaviour and plays significant position in its “utilization” as “electrical and heat insulation”. However, numerous “researchers have studied” thermo-physical properties of soil. Still, the study on the relationship between soil's properties and its cooling effect through evaporation has not been investigated in detail. In this analysis, soil samples and earthen pots were collected from four states of India: Haryana, Delhi, Rajasthan, and Uttar Pradesh. The performance parameters used to evaluate the cooling effect of the soil, and earthen pot samples are “water-holding capacity”, porosity, “thermal-conductivity”, texture, and particle and bulk density. The application of “high temperature” fluctuate the “internal microstructure” of clay/soil and subsequently disturbs its “physical and thermal properties”. The sand/clay is converted into an earthen pot by applying high temperatures in kilns. The pot samples collected are heated in kilns to bring them to the final form for the study. We are studying the properties after that treatment. In this paper, the impact of “firing temperature” (maximum 900°C) on the “thermo-physical properties” of earthen pots made up of soil of a similar kind as the soil samples collected and the impact of thermo-physical properties on the cooling of the earthen pots has been examined via experiments. The results specify that the “thermal conductivity” of soil/clay samples is less compared to earthen pot. The “porosity and water-holding capacity” of the soil are greater than earthen pots because pore space or pore volume has decreased due to the heating effect. From the experimental analysis, it was found that the soil of the Sohna location in Haryana state has a high water cooling capacity due to its high water-holding (49.28%) capacity and porosity (48.75%). The pot made out of clay, having higher porosity, and water-holding capacity, gives the maximum cooling temperature.

Early Evidence That Soil Dryness Causes Widespread Decline in Grassland Productivity in China

The burning of fossil fuels by humans emits large amounts of CO2 into the atmosphere and strongly affects the Earth’s carbon balance, with grassland ecosystems changing from weak carbon sinks that were previously close to equilibrium to core carbon sinks. Chinese grasslands are located in typical arid–semi-arid and semi-arid climatic regions, and drought events in the soil and atmosphere can have strong and irreversible consequences on the function and structure of Chinese grassland ecosystems. Based on this, we investigated the response of the gross primary production (GPP) of Chinese grasslands to land–atmosphere moisture constraints, using GPP data simulated through four terrestrial ecosystem models and introduced copula functions and Bayesian equations. The main results were as follows: (1) Soil moisture trends were not significant, and changes were dominated by interannual variability. The detrended warm-season SM correlated with GPP at 0.48 and 0.63 for the historical and future periods, respectively; thus, soil moisture is the critical water stress that regulates interannual variability in Chinese grassland GPP. (2) The positive correlation between shallow SM (0–50 cm) and GPP was higher (r = 0.62). Shallow-soil moisture is the main soil layer that constrains GPP, and the soil moisture decrease in shallow layers is much more likely to cause GPP decline in Chinese grasslands than that in deep-soil water. (3) The probability of GPP decline in Chinese grasslands caused by drought in shallow soils of 0–20 and 20–50 cm is 32.49% and 27.64%, respectively, which is much higher than the probability of GPP decline in deeper soils. In particular, soil drought was more detrimental to grassland GPP in Xinjiang and the Loess Plateau. (4) The probability of soil drought causing GPP decline was higher than that of atmospheric drought during the historical period (1.78–8.19%), but the probability of an atmospheric drought-induced GPP deficit increases significantly in the future and becomes a key factor inhibiting GPP accumulation in some regions (e.g., the Loess Plateau). Our study highlighted the response of grassland ecosystems after the occurrence of soil drought, especially for the shallow-soil-water indicator, which provides important theoretical references for grassland drought disaster emergency prevention and policy formulation.

Response characteristics of an insertion tensiometer investigated via the vacuum saturation method

Tensiometers are devices that can be used to monitor suction variation in landslides and slopes. The soil suction that can be measured with a conventional tensiometer is limited to 85 ∼ 90 kPa due to water cavitation in the tensiometer. This low measurement range of suction may be insufficient to interpret and determine the hydraulic properties of unsaturated soil, especially in semihumid and semiarid climate regions. However, in most geotechnical engineering studies, conventional tensiometers are still utilized. Although several types of high-suction tensiometers have been developed in recent decades, high suction measurements are difficult in the field because the saturation procedures for these tensiometers are complex and time consuming. Hence, the development of a simple and rapid saturation method is necessary to support their application. The vacuum saturation technique is a simple and reliable technique for saturating the porous ceramic cup of a tensiometer. However, if a high-suction tensiometer is saturated via a vacuum syringe, the measurable maximum suction is usually<200 kPa, which limits the application of tensiometers in geotechnical engineering. In this paper, we proposed a simple saturation device and a saturation method (the vacuum cylinder saturation method, VCSM) to saturate high-suction tensiometers. Soil column experiments were conducted to investigate the advantages of the VCSM and the response characteristics of insertion tensiometers. The results indicated that high-suction tensiometers could easily and steadily measure a maximum suction of 350 kPa if saturated via the VCSM. The VCSM could effectively prevent or retard the occurrence of cavitation due to the high vacuum pressure and slow progress of water filling in the tensiometer shaft. In addition, the response curve of insertion tensiometers could be divided into three stages: installing disturbance stage, delayed response stage and equilibrium stage. The extent of the disturbance caused by insertion tensiometer installation is a key factor influencing the delayed response characteristics of the tensiometer response curve. This paper also provides greater insight into the saturation method of tensiometers and the application of insertion tensiometers.

Towards the effects of moss-dominated biocrusts on surface soil aeration in drylands: Air permeability analysis and modeling

Soil aeration is an important factor influencing soil biological and biochemical processes because it directly affects soil microbial activity and respiration. As an important living skin of the soil, biocrusts strongly impact various soil properties and play a vital role in maintaining surface soil structure and multifunctionality. Although there are several studies concerning the effects of biocrusts on soil respiration processes, it is still not well understood how biocrusts affect air permeability (Ka) and soil aeration in drylands. In a semiarid climate region of the northern Chinese Loess Plateau, the Ka and air-filled porosity (εa) of moss-dominated biocrusts established on aeolian sand and loess soil were measured as a function of soil water content under laboratory and in situ conditions and compared to measurements of bare soils. The relative air permeability (Kra) of biocrusts and bare soils was further analyzed and estimated with commonly applied Kra models that are based on the soil water retention curve (SWRC), and the performance of these models was specifically assessed for biocrusts. The in situ measurements yielded a 51.8% and 76.7% higher Ka for the biocrust-colonized aeolian sand and loess soil, respectively, when compared to the bare soils. Correspondingly, in comparison to the bare soils, the εa of the biocrusts also increased by 38.0% for the aeolian sand and by 52.4% for the loess soil. The laboratory measurements showed an 8.5%–9.3% increase of Ka for the biocrust-colonized soils from wet to dry conditions when compared to their bare counterparts, which was mainly attributed to their higher fine particle and organic matter contents as well as to the moss rhizoids. Moreover, a positive linear relationship (R2 > 0.43) was found between the log Ka and log εa for both biocrusts and bare soils. Additionally, the biocrusts exhibited higher water content at almost all matric potentials in comparison to the bare soils. The Kra of biocrusts was 22.0% higher for aeolian sand and 42.1% higher for loess soil when compared to the bare soils. The van Genuchten-Burdine and Brooks and Corey-Burdine models performed best with regard to the estimation of Kra (RMSE ≤ 0.100, bias ≤ 0.018). In general, biocrusts may greatly increase surface soil aeration due to their higher Ka and εa, and the soil aeration status of biocrusts can be indirectly assessed through their effective degree of soil water saturation. Our findings suggest that biocrusts should be carefully considered in further studies of soil aeration related to biological processes and gas and vapor transport in dryland ecosystems.