Search Results (1,574)

Breeding wheat varieties that are resilient to arid climates, which impart a complex combination of stresses, including excessive Ca, high pH, nutrient deficiency, and aridity, is important. Afghan landrace wheat is assumed to have evolved with a specific prototypical pattern of traits to adapt to its challenging, composite stress environment. Here, a useful semi-hydroponic double cup screen aiding proteomic analysis was exploited to reconstruct the combined excessive Ca²⁺ (100 ppm) and extreme pH (11.0) of the soils and to dissect specific morpho-physiological characteristics and adaptation strategies in Kihara Afghan landrace wheat (KAWLR). When compared to other cultivars and growth habits, several winter-type KAWLR showed lower unused N-K-P and greater rhizosphere pH stability in the bottom cup and higher tolerance in terms of greater root allocation shift, and most of their above ground traits (shoot biomass, chlorophyll content, and stomatal conductance) were strongly correlated with root length and biomass under stress conditions. Quantitative proteomics on the roots of a tolerant winter-type KAWLR, Herat-740 (KU-7449), showed a strong decreasing trend in changed proteins (12 increased/816 decreased). The proteins (such as mitochondrial phosphate carrier protein, cytoskeleton-related α-, and β- tubulin) that increased in abundance were associated with energy transport and cell growth. A metabolism overview revealed that most proteins that were mapped to glycolysis, fermentation, and the TCA cycle decreased in abundance. However, proteins related to cell wall and lipid metabolism pathways remained unchanged. Our results suggest that winter-type KAWLR adopts a homeostatic stress adaptation strategy that globally downshifts metabolic activity, while selectively maintaining root growth machinery. Root allocation shift, rhizosphere pH stabilization (nutrient solubilization), and a selective proteome response maintaining the root growth machinery in winter-type KAWLR could be breeding selection markers for early-stage screening in calcareous-alkaline arid land. Full article

The infiltration process is an essential element of the hydrological cycle and water management. To provide a consideration for selecting an infiltration model and setting parameter values in the Oum Zessar watershed, the effectiveness of four infiltration models—Horton, Philip, Kostiakov, and Green–Ampt—is systematically evaluated using infiltration rate data measured in several field locations. The constant infiltration rate (CIR) of several locations was assessed using the double-ring infiltrometer technique and juxtaposed with values derived from the models. The parametric equations of each model were calibrated using time-series infiltration data obtained from the experimental observations. Excel functions were used to simplify the intricate mathematical calculations of the parameters. The model’s accuracy was assessed using six statistical metrics: Root Mean Square Error (RMSE), Sum of Squared Errors (SSE), Standard Error (STD ERR), and bias, along with the highest values of Nash–Sutcliffe Efficiency (NSE) and correlation (CORR). The greatest values of NSE and CORR, along with the lowest values of RMSE, SSE, STD ERR, and bias, indicate the optimal model. Moreover, the Model Performance Index (MPI) was implemented to evaluate the effectiveness of the modules by providing a clear scoring system for the models. The obtained results indicated that Kostiakov model displays the optimal fitting values on all indicators and locations, and the Horton model showed the second-best fitting values in most of the indicators. Full article

Background/Objectives: The escalating antimicrobial resistance crisis underscores the urgent need to explore underexplored ecological niches as reservoirs of novel bioactive compounds. The Brazilian Caatinga, a unique semi-arid biome, represents a promising reservoir for microbial discovery. Methods: In this study, we report the polyphasic characterization of Streptomyces galbus I339, a strain isolated from Caatinga soil. Whole-genome sequencing and phylogenomic analysis confirmed its taxonomic identity. In silico mining of the genome was conducted to assess biosynthetic potential. This genetic promise was experimentally validated through an integrated metabolomic approach, including liquid chromatography-tandem mass spectrometry (LC-MS/MS), nuclear magnetic resonance (NMR) spectroscopy, and gas chromatography-mass spectrometry (GC-MS) profiling. The anti-mycobacterial activity of the crude extract was evaluated against Mycobacterium tuberculosis. Results: The strain S. galbus I339 possesses a 7.55 Mbp genome with a high GC content (73.17%). Genome mining uncovered a remarkable biosynthetic potential, with 45 biosynthetic gene clusters (BGCs) predicted, including those for known antibiotics like actinomycins, as well as numerous orphan clusters. Genome mining uncovered a remarkable biosynthetic potential, with 45 biosynthetic gene clusters (BGCs) predicted, including those for known antibiotics like actinomycins, as well as numerous orphan clusters. Metabolomic analyses confirmed the production of actinomycins and identified abundant diketopiperazines. Furthermore, the crude extract exhibited antimycobacterial activity, with a potent MIC of 0.625 µg/mL. Conclusions: The convergence of genomic and metabolomic data not only validates the expression of a fraction of this strain’s biosynthetic arsenal but also highlights a significant untapped potential, with the majority of BGCs remaining silent under the tested conditions. Our work establishes S. galbus I339 as a compelling candidate for biodiscovery and underscores the value of integrating genomics and metabolomics to unlock the chemical diversity of microbes from extreme environments. Full article

Understanding how cultivated xerophytic shrubs physiologically regulate canopy water loss under anomalously wet conditions is crucial for predicting ecohydrological responses and for providing practical guidance in landscape restoration under the ongoing warming–wetting trend on the northern Loess Plateau. This study tested hypotheses concerning the hierarchy of atmospheric and soil-water controls on canopy transpiration (E_c), stomatal conductance (g_s), the strength of canopy–atmosphere coupling, and species-specific soil-water sensitivities and water-use strategies in Caragana korshinskii and Salix psammophila. Concurrent measurements of branch-level sap flow, meteorological variables, and soil water content (SWC) at multiple depths were conducted in two adjacent stands during the wet season of a climatically wet year (July–September 2017). Meteorological factors, particularly vapor pressure deficit (VPD), were the dominant drivers of daily E_c and g_s, whereas SWC exerted secondary but species-specific influences. Both shrubs were strongly coupled to the atmosphere, with consistently low decoupling coefficients (Ω ≈ 0.11–0.15) on daily scales. C. korshinskii maintained stable water use through access to deeper soil, whereas S. psammophila responded sensitively to fluctuations in shallow SWC. These contrasting patterns indicate depth-partitioned water-use strategies and a context-dependent continuum between isohydric and anisohydric behavior rather than fixed species traits. The findings support improved parameterization of shrub water use in ecohydrological models, more effective water-use management, and informed species selection and nursery practices for landscape restoration in semi-arid regions experiencing warming–wetting climatic shifts. Full article

Understanding the factors that structure freshwater invertebrate assemblages is essential for predicting biodiversity patterns across heterogeneous landscapes. Here, we provide the first comprehensive assessment of ostracod diversity across multiple freshwater ecoregions of Botswana, a semi-arid country encompassing a wide range of hydrological and climatic conditions. We analyzed ostracod assemblages from 19 sites, integrating spatial, regional, and local environmental variables with biotic predictors derived from macro-, meio-, and microinvertebrate communities. Multivariate analyses revealed that spatial variables, strongly correlated with bioclimatic gradients, were the dominant predictors of ostracod assemblage composition. These gradients reflected broad-scale climatic differences among ecoregions and explained substantially more variation than local physical and chemical water properties. Biotic interactions, represented by taxonomic and functional composition of associated invertebrates and vegetation type, also significantly contributed to model performance, highlighting their previously underappreciated role in shaping ostracod assemblages. Local abiotic environmental factors had comparatively weak explanatory power. Our findings demonstrate that ostracod diversity in Botswana is primarily structured by large-scale spatial–bioclimatic patterns, with additional influence from biotic interactions. This study provides new insights into the ecological drivers of freshwater microcrustaceans in semi-arid regions and establishes a baseline for future biodiversity assessments in southern Africa. Full article

Wildfire occurrence in arid and semiarid landscapes is increasingly driven by shifts in climatic and biophysical conditions, yet its dynamics remain poorly understood in the mountainous environments of western Saudi Arabia. This study modeled wildfire probabilities across the Aseer, Al Baha, Makkah Al-Mukarramah, and Jazan regions via multisource Earth observation datasets from 2012–2025. Active fire detections from VIIRS were integrated with ERA5-Land reanalysis variables, vegetation indices, and Copernicus DEM GLO30 topography. A random forest classifier was trained and validated via stratified sampling and cross-validation to predict monthly burn probabilities. Calibration, reliability assessment, and independent temporal validation confirmed strong model performance (AUC-ROC = 0.96; Brier = 0.03). Climatic dryness (dew-point deficit), vegetation structure (LAI_lv), and surface soil moisture emerged as dominant predictors, underscoring the coupling between energy balance and fuel desiccation. Temporal trend analyses (Kendall’s τ and Sen’s slope) revealed the gradual intensification of fire probability during the dry-to-transition seasons (February–April and September–November), with Aseer showing the most persistent risk. These findings establish a scalable framework for wildfire early warning and landscape management in arid ecosystems under accelerating climatic stress. Full article

Evapotranspiration (ET) is challenging to measure directly, motivating the use of remote sensing products as alternatives. We evaluated five high-resolution (≤1 km) global ET products (SSEBop, MOD16, ETMonitor, PMLv2, and FAO’s WaPOR) against five eddy covariance (EC) measurements in Morocco’s semi-arid Tensift Al-Haouz region, with observations spanning from 2006 to 2019. These five products were selected because they offer the finest spatial resolution (around 1 km or less) among freely downloadable global ET datasets, making them well-suited for comparison with local EC flux tower data. The study area was chosen for its reliable ground-truth EC stations, extensive knowledge of local irrigation practices, and a semi-arid climate that provides a rigorous testbed for ET model evaluation in water-limited conditions. Precipitation observations were included to assess each product’s sensitivity to soil moisture and precipitation-driven ET variations, particularly to identify which models respond to rainfall and irrigation inputs (i.e., differences between rainfed and irrigated fields). Results indicate that PMLv2 achieved the best agreement with EC (R² up to 0.65, RMSE as low as 0.4 mm/day, and PBIAS under 10% at most sites), followed by WaPOR and SSEBop which captured seasonal ET patterns (R² ~0.3–0.5) with moderate bias (~20–30%). In contrast, ETMonitor and MOD16 underperformed, showing larger errors (RMSE ~1–2.5 mm/day) and substantial underestimation biases (e.g., MOD16 PBIAS ~50–80% in irrigated sites). These findings underscore the impact of algorithmic differences and highlight PMLv2, SSEBop, and WaPOR as more reliable options for estimating ET in semi-arid agricultural regions lacking in situ measurements. Full article

Agriculture in semi-arid regions faces challenges, such as water scarcity and low soil fertility, making the forage cactus a highly important crop due to its crassulacean acid metabolism (CAM) pathway. The productivity of the forage cactus, however, depends on proper water and nutrient management, especially nitrogen. Despite its importance, there is little research into the effects of nitrogen fertilisation on productive, photochemical, physiological and biochemical parameters, or on intercropping systems. Increasing doses of nitrogen are assumed to enhance CAM pathway, improving productivity, gas exchange, photochemical efficiency and antioxidant accumulation, in addition to mitigating the effects of oxidative stress under adverse conditions. The experiment was conducted in Serra Talhada, Pernambuco, Brazil, in a randomised block design with four replications. Changes in the biometric, productive, photochemical, physiological and biochemical parameters were evaluated in forage cactus intercropped with sorghum (Sorghum bicolor) or pigeon pea (Cajanus cajan) subjected to different doses of nitrogen (0, 75, 150, 300 and 450 kg ha⁻¹). The results showed that nitrogen fertilisation promoted a higher photosynthetic rate and greater stomatal conductance, increased transpiration, and higher levels of pigment and soluble proteins, in addition to reducing lipid peroxidation. Our findings revealed that the cactus—pigeon pea intercropping system has better photosynthetic, enzymatic and productive performance at a dose of 150 kg N ha⁻¹, whereas the cactus—sorghum intercropping system required 450 kg N ha⁻¹ to achieve similar results. Overall, proper nitrogen management in intercropping systems can optimise the physiological performance and productivity of the forage cactus in semi-arid environments. Full article

Nitrogen deficiency is a major constraint on maize (Zea mays L.) productivity in Afghanistan, where poor soil fertility limits yields. This study investigated the effect of urea fertilizer on maize growth, physiology, and yield under semi-arid conditions in Balkh Province with a Calcisols soil type, focusing on maize cultivated for grain production. A field experiment was conducted in 2019 using a randomized complete block design with three replications and four nitrogen levels: 0 (control), 38.4, 76.8, and 115.2 kg ha⁻¹. The region consists of fertile alluvial plains suitable for crop cultivation, though maize productivity is constrained by soil nutrient limitations, especially nitrogen deficiency. The soil at the experimental site is silty loam in texture, moderately fertile with alkaline pH (8.1), low organic matter (0.5%), and limited available nitrogen (15 mg kg⁻¹). Growth traits (plant height, leaf number, leaf area, SPAD value), physiological parameters (leaf area index, crop growth rate, biomass), and yield components (cob length, cob diameter, seed number, 100-seed weight, biological yield, and Brix content) were recorded. Results showed that nitrogen application significantly improved all traits compared to the control. The highest values for plant height (260.2 cm), cob length (31.67 cm), biological yield (216.6 t ha⁻¹), and Brix content (8.6%) were observed at 115.2 kg ha⁻¹, although 76.8 kg ha⁻¹ produced nearly similar results. Correlation analysis revealed strong positive associations between SPAD values, vegetative traits, and yield. The findings indicate that 115.2 kg ha⁻¹ urea is an efficient and practical nitrogen rate for enhancing maize productivity under Afghan conditions. Full article

The Tarim Basin is currently the largest petroliferous basin in China, with hydrocarbons primarily hosted in Ordovician marine carbonate paleokarst fracture–vug reservoirs—a typical example being the Tahe Oilfield located in the northern structural uplift of the basin. The principle of “the present is the key to the past” serves as a core method for studying paleokarst fracture–vug reservoirs in the Tahe Oilfield. The deep and ultra-deep carbonate fracture–vug reservoirs in the Tahe Oilfield formed under humid tropical to subtropical paleoclimates during the Paleozoic Era, belonging to a humid tropical–subtropical paleoepikarst dynamic system. Modern karst types in China are diverse, providing abundant modern karst analogs for paleokarst research in the Tarim Basin. Carbonate regions in Eastern China can be divided into two major zones from north to south: the arid to semiarid north karst and the humid tropical–subtropical south karst. Karst in Northern China is characterized by large karst spring systems, with fissure–conduit networks as the primary aquifers; in contrast, karst in Southern China features underground river networks dominated by conduits and caves. From the perspective of karst hydrodynamic conditions, the paleokarst environment of deep fracture–vug reservoirs in the Tarim Basin exhibits high similarity to the modern karst environment in Southern China. The development patterns of karst underground rivers and caves in Southern China can be applied to comparative studies of carbonate fracture–vug reservoir structures in the Tarim Basin. Research on modern and paleokarst systems complements and advances each other, jointly promoting the development of karstology from different perspectives. Full article

This narrative review aims to summarize, synthesize, and organize current knowledge on the adaptation of sheep and goats to stressful environments and to discuss how these adaptations contribute to food security in vulnerable communities. A structured search of Web of Science, Scopus, PubMed, and Google Scholar was conducted using combinations of terms related to sheep and goats, harsh environments (e.g., arid and semi-arid regions, heat stress, water restriction, poor-quality forage), and adaptation or resilience, combined with Boolean operators. A total of 1718 research publications were found, of which 86 were retained as the most relevant because they provided direct and detailed evidence on anatomical, physiological, digestive–microbiome, behavioral, and genomic adaptations of sheep and goats to stressful environments. The selected studies describe a wide range of phenotypic and integumentary traits, thermoregulatory and endocrine responses, digestive and microbial adjustments, behavioral strategies, and genomic signatures that, together, allow small ruminants to maintain basic functions, reproduction, and production under conditions of climatic and nutritional stress. Evidence from these studies also highlights how adaptive traits support herd productivity, economic stability of households, and the sustainable use of natural resources in regions where climatic variability and resource scarcity are common. Overall, the synthesis presented here underscores the importance of conserving and strategically using locally adapted sheep and goat breeds, incorporating resilience-related traits into breeding and management programs, and prioritizing further research on genomic, microbiome, and epigenetic mechanisms that underpin adaptation to harsh environments. Full article

Waste generated from agricultural activities is anticipated to increase in the future, especially in less developed countries, and this could cause environmental health risks if these wastes are not well managed. The anaerobic digestion (AD) by co-digesting organic waste is a technology used to produce biogas while utilizing biodigestate as a biofertilizer; however, AD requires a lot of water to be efficient, which could pose water challenges to arid areas. This study evaluated biogas production under semi-dry conditions by augmenting the process with a high-water content wild melon and determined the nutrient composition of the resultant biodigestate. Batch studies of AD were performed to evaluate methane potential of the different animal waste using an online and standardized Automatic Methane Potential Test System (AMPTS) II light for approximately 506 h (21 days) at 38 °C. The highest biomethane potential (BMP) determined for mono and co-substrate digestion was 29.5 NmL CH₄/g VS (CD) and 63.3 NmL CH₄/g VS (CMWM), respectively, which was calculated from AMPTS biomethane yield of 3166.2 NmL (CD) and 1480.6 NmL (CMWM). Water-displacement method was also used to compare biogas yield in wet and semi-dry AD. The results showed high biogas yield of 8480 mL for CM (mono-substrate) and 10,975 mL for CMCC in wet AD. Semi-dry AD was investigated by replacing water with a wild melon (WM), and the highest biogas production was 8000 mL from the CMCC combination augmented with WM. Generally, in wet AD, co-digestion was more effective in biogas production than mono-substrate AD. The biodigestate from different substrate combinations were also evaluated for nutrient composition using X-ray Fluorescence (XRF) analysis, and all the samples contained fair amount of essential nutrients such as calcium (Ca), phosphorus (P), potassium (K) and microelements such as chloride (Cl), magnesium (Mn), iron (Fe), zinc (Zn). This study successfully implemented semi-dry AD from co-digested animal wastes to produce biogas as an energy solution and biofertilizer for crop production, thereby creating a closed-loop system that supports a circular bioeconomy. In addition, the study confirmed that lowering the water content in the AD process is feasible without compromising substantial biogas production. This technology, when optimized and well implemented, could provide sustainable biogas production in areas with water scarcity, therefore making the biogas production process accessible to rural communities. Full article

With its millennia-long agricultural history, Olive (Olea europaea L.) is one of the most strategic crops of the Mediterranean basin and a key component of the Turkish economy. This study assessed the effects of climate change on the potential distribution of olive in Türkiye using machine learning-based species distribution models (SDMs). Analyses were conducted using the 1970–2000 reference period and future projections for 2041–2060 and 2081–2100 under the SSP2-–4.5 and SSP5–8.5 scenarios, incorporating bioclimatic variables as well as topographic factors such as elevation, slope, and aspect. The model showed strong predictive performance (AUC = 0.93; TSS = 0.77) and identified elevation, winter precipitation (Bio19), and mean temperature of driest quarter (Bio9) as the primary variables influencing the distribution of olive trees. Model results predict a significant shift in suitable areas for olive cultivation, both northward—from the traditional Aegean and Mediterranean coastal belt toward the Marmara and Black Sea regions—and upward in elevation into higher-altitude inland areas. High-suitability areas, which accounted for 4.4% of Türkiye’s land area during the reference period, are projected to decline to 0.2% by the end of the century under the SSP5–8.5 scenario. UNEP Aridity Index analyses indicate increasing aridity pressure on olive habitats. While 87.2% of suitable habitats were classified as sub-humid in the reference period, projections for 2081–2100 under SSP5–8.5 suggest that 40.1% of these areas will shift to dry sub-humid and 26.4% to semi-arid conditions. Full article

Nickel contamination poses a serious risk to ecosystems and human health. Phytoremediation provides a sustainable solution. This study evaluates the ability of Helinathus annuus L. to tolerate and accumulate nickel under simulated Mediterranean and semi-arid conditions, representing a short-term contamination event with nickel-enriched irrigation. Laboratory experiments assessed growth, tolerance, and Ni distribution within plant tissues. Results showed that Ni uptake increased with concentration, mainly in roots, while translocation to aerial parts remained limited. The bioconcentration factors ranged from 1.32 to 2.55, and the translocation factors from 0.46 to 0.60, indicating efficient uptake but restricted metal mobility. Higher water availability enhanced Ni absorption, suggesting that soil moisture facilitates metal transport and root activity. Helinathus annuus L. demonstrated good tolerance at moderate Ni levels but reduced growth and accumulation efficiency at higher concentrations, confirming its potential for phytostabilization in Mediterranean soils affected by metal contamination. Full article

Managing hydraulic behaviour and water quality in semi-arid, transboundary rivers such as the Talas River in Kazakhstan requires reliable numerical tools for predicting free-surface flow through porous hydraulic structures. This study develops and verifies a two-dimensional computational fluid dynamics (CFD) framework for simulating free-surface water flow through porous media and demonstrates its applicability to a real river reach of the Talas in the Zhambyl region. The model combines the Volume of Fluid (VOF) method with the Darcy–Forchheimer formulation to represent porous resistance, while turbulence is described by the RNG k–$\epsilon$ model, and pressure–velocity coupling is handled by the PISO algorithm. Model verification is conducted against a classic dam-break experiment involving a rectangular porous barrier across a laboratory channel. The simulations successfully reproduce the main experimental observations, including rapid drawdown after gate opening, formation and attenuation of the free-surface wave, localized depression above the porous insert, and the subsequent approach to a quasi-steady state. Time histories of water levels at control points and the spatial progression of the wet front show close agreement with measurements. Using the validated setup, a site-specific two-dimensional domain for the Talas River is constructed to analyse the hydraulic influence of a porous bar. The model quantifies velocity redistribution and energy dissipation across the porous patch and provides physically consistent flow fields suitable for engineering assessments under various discharge conditions. Full article