Search Results (1,158)

Drought stress is one of the major abiotic factors limiting crop growth and yield, particularly in wheat. Water deficit leads to reduced chlorophyll content, impaired photosynthetic performance, and decreased biomass accumulation. Nitrogen fertilization may influence plant physiological responses to drought; however, its capacity to alleviate drought-induced growth reduction remains uncertain. A pot experiment was conducted to evaluate the impact of different nitrogen-based fertilizers on wheat seedlings grown under irrigation level 60% PPW (control) and 30% PPW (drought stress) conditions, with balanced levels of phosphorus and potassium maintained in all treatments. Water deficit led to substantial reductions in chlorophyll content compared to optimally irrigated plants. Similarly, the performance index (PI) decreased by 139.3% at Term 1 (1 day after foliar nitrogen application) and 27.2% at Term 2 (7 days after application). The net photosynthetic rate (Pn) declined markedly under drought conditions and was not significantly improved by nitrogen fertilization, indicating a partial and mainly short-term physiological response to nitrogen under water deficit. The application of nitrogen fertilizers, particularly urea and Nitron S, modulated the relative chlorophyll content and selected chlorophyll fluorescence (Fv/Fm, Fv/Fo, PI) and gas-exchange (E, gs, Ci) parameters under drought conditions, mainly shortly after application. However, aboveground dry biomass under drought conditions was not significantly affected by any nitrogen fertilizer. Urea induced the most consistent short-term physiological responses under both irrigation regimes, with effects more pronounced shortly after application, whereas Nitron S showed fertilizer-specific effects under drought stress. Overall, the results demonstrate that foliar nitrogen fertilization can modulate short-term physiological responses of wheat seedlings to drought but does not translate into sustained improvements in Pn or biomass accumulation. In the context of climate change and increasing water scarcity, identifying nitrogen fertilizers that support physiological functioning without overestimating growth benefits has critical implications for sustainable wheat production. Optimizing nitrogen fertilization may, therefore, contribute to improved nutrient management strategies under water-limited conditions. Full article

Nature-based Solutions (NbS) such as rolled cover crops are increasingly adopted in rainfed vineyards to reduce soil degradation and drought risk, but their effectiveness depends on local soil physical conditions. We compared spontaneous inter-row vegetation managed by mowing (Control) with a cereal-based rolled cover crop (C-R) in two vineyards of the Oltrepò Pavese (Northern Italy) with contrasting texture, structure, and slope: Canevino (CNV) and Santa Maria della Versa (SMV). From 2021 to 2025, continuous soil moisture monitoring was combined with field measurements of saturated hydraulic conductivity (K_s) and bulk density, interpreted using temporal indicators (MRD, ITS) and a drought index (SWDI) calibrated to field moisture thresholds. During wet phases, average saturation at 50 cm was consistently higher at SMV (about 78 to 84 percent) than at CNV (about 68 to 75 percent). Under water-limited conditions, management contrasts were most evident at SMV: at 50 cm during the post-termination dry phase, saturation remained around 70 percent under C-R versus about 64 percent under the Control, and K_s was higher under C-R (8.32 × 10⁻⁶ m/s in topsoil) than under the Control (7.39 × 10⁻⁶ m/s). At CNV, SWDI at 50 cm indicated a moderate improvement in one agronomic year (median −1.2 under C-R versus −5.3 under the Control in 2021 to 2022), while a full tillage operation in 2024 defined a disturbed phase that was interpreted separately. SWDI occasionally suggested severe drought levels not fully matching field evidence, highlighting the need for site-calibrated reference thresholds in structured fine-textured soils. Overall, soil physical properties set the hydrological envelope, while rolled cover management can enhance buffering and preserve conductive pathways during dry phases; therefore, NbS performance should be evaluated with site-adapted monitoring and cautious inference from temporally autocorrelated time series. Full article

The subject of this research is the exploration of the potential of remote sensing and Geographic Information Systems (GIS) for basin-scale spatio-temporal monitoring of drought and its impacts in the Ukrina River Basin, Bosnia and Herzegovina (BH), during the last decade (2015–2024). The aim is to integrate meteorological, hydrological, agricultural, and socio-economic drought signals and to delineate areas of long-term drought exposure. Meteorological drought was evaluated using CHIRPS precipitation and the Standardized Precipitation Index (SPI) calculated at 1-, 3-, 6-, and 12- month accumulation scales using Gamma fitting and a fixed long term reference period; hydrological drought was examined using available water-level records complemented by the Standardized Water Level Index (SWLI) and supported by correspondence with standardized ERA5-Land runoff anomalies; agricultural drought was mapped using remote sensing indices—the Temperature Condition Index (TCI), Vegetation Condition Index (VCI), and Vegetation Health Index (VHI)—calculated from MODIS satellite data; and socio-economic effects were assessed using municipal crop-production statistics (2015–2019). The results indicate that drought conditions were most pronounced in 2015, 2017, 2021, and especially 2022, showing consistent agreement between precipitation deficits, hydrological responses, and vegetation stress, while 2016, 2018–2020, 2023, and 2024 were generally more favorable. As a key novelty, a persistent drought-prone zone was delineated by intersecting drought-affected areas across major episodes, providing a basin-scale identification of chronic drought hotspots for a river basin in BH. The persistent zone covers 40.02% of the basin and spans nine cities and municipalities, with >93% located in Prnjavor, Derventa, Stanari, and Teslić. Hotspots are concentrated mainly in lowlands below 400 m a.s.l., with a statistically significant concentration across lower elevation classes, indicating higher long-term exposure in the central and northern valley sectors, and land use overlay further highlights high relative exposure of productive land. Overall, the integrated remote sensing and GIS framework strengthens drought monitoring by providing spatially explicit and repeatable evidence to support targeted adaptation planning and drought-risk management. Full article

Hazelnut (Corylus avellana L.) cultivation in Italy is facing constraints related to climate change, causing decreases in production as a consequence of summer droughts and late spring heatwaves. This two-year study (2024–2025, i.e., Y1 and Y2) evaluated the effectiveness of two biostimulant protocols on the eco-physiological and productive performance of a hazelnut orchard (cv ‘Tonda Gentile Romana’) in Central Italy. Treatment A included a mixture of formulations (silicon, Ecklonia maxima and microalgae), while Treatment B featured an Ecklonia maxima-containing biostimulant. Data-gathering combined ground-level measurements and remote-sensing technologies, which allowed for the extraction and assessment of vegetation indexes such as the Normalized Difference Vegetation Index (NDVI), the Normalized Difference Red Edge Index (NDRE) and the Normalized Difference Moisture Index (NDMI). Treatments A and B successfully maintained higher chlorophyll content; this beneficial effect was validated by the NDVI, but the NDRE might have suffered from soil interference due to its high sensitivity. The NDMI was positively influenced by both treatments. Treatment A brought to a remarkable production increase in both seasons, especially in Y1 with 7.75 kg plant⁻¹ (+40% vs. Control) and without negatively affecting the shell/nut ratio. These findings suggest that biostimulants could represent an effective strategy for improving productivity and enhancing abiotic stress resilience in hazelnut cultivation. Full article

Drought remains a phenomenal disaster of critical concerns in West Africa, particularly within the Niger River Basin, due to its insidious, multifaceted, and long-lasting nature. Its continuous severe impacts on communities, combined with the limitations of existing univariate index-based monitoring methods, worsen the challenge. This paper introduces and evaluates a Hybrid Drought Resilience Empirical Model (DREM) that integrates meteorological, agricultural, and hydrological indicators to improve their concurrent monitoring and early warning for effective decision-making in the region. Using reanalysis hydrometeorological data (1980–2016) and community vulnerability records, results show that the DREM-based composite index detects drought earlier than the Standardized Precipitation Index (SPI), with stronger alignment to soil moisture and streamflow variations. The model identifies drought onset when thresholds range from −0.26 to −1.19 over three consecutive months, depending on location, and signals drought termination when thresholds rise between −0.08 and −0.82. The study concludes that the DREM-based composite index provides a more reliable and integrated framework for early drought detection and decision-making across the Niger River Basin, and hence, has proven to be a suitable drought monitor for stakeholders in the Niger Basin which can be relied upon and trusted with high confidence. Full article

Heat and high-irradiance stress increasingly threaten almond production in Mediterranean environments, where rising temperatures and prolonged summer droughts impair photosynthetic performance and yield. This study evaluated the effectiveness of three mineral-based shielding materials: kaolin, basalt powder, and zeolite. We hypothesized that the foliar application of reflective mineral materials would reduce leaf temperature, enhance photosynthetic efficiency, and improve yield without altering nut nutraceutical quality. A two-year field experiment (2024–2025) was conducted using a randomized block design with four materials (untreated control, kaolin, basalt powder, and zeolite). Physiological traits (gas exchange, chlorophyll fluorescence, leaf temperature, and SPAD index), morpho-biometric and biochemical parameters, and yield components were assessed. Kaolin and basalt powder significantly lowered leaf temperature (−1.6 to −1.8 °C), increased stomatal conductance and net photosynthesis, and improved photochemical efficiency (Fv′/Fm′) and electron transport rates. These treatments also enhanced drupe weight, kernel dry matter, and productive yield (up to +32% compared with the control). Zeolite produced positive but less prominent effects. No significant differences were detected in fatty acid profile, total polyphenols, or antioxidant capacity, indicating that the materials did not affect almond nutraceutical quality. Principal component analysis confirmed the strong association between kaolin and basalt powder and improved eco-physiological performance. Overall, mineral shielding materials, particularly kaolin and basalt powder, represent a promising, sustainable strategy for enhancing almond orchard resilience under Mediterranean climate change scenarios. Full article

(1) Background: This study used Qingjian No. 1 forage pea (Pisum sativum L.) as a plant material to study its metabolic mechanisms in response to different stresses, given that saline–alkali stress and drought stress often occur simultaneously in natural environments and severely affect the growth and yield of forage pea, while the regulatory network underlying the adaptation of forage pea to combined stress remains poorly elucidated. (2) Methods: The metabolic mechanisms of forage pea in response to different stresses were elucidated by integrating phenotypic, physiological, and metabolomic analyses. (3) Results: The results show that compared to the control, all stress treatments significantly inhibited seed germination and seedling growth, with the combined saline–alkali and drought stress exhibiting the strongest inhibitory effect. In terms of physiological and biochemical responses, peroxidase (POD) activity increased with the complexity of the stress, with the highest POD activity observed under combined saline–alkali and drought stress, showing a 61.71% increase compared to the control (p < 0.05). Non-targeted metabolomic analysis revealed that isoflavone biosynthesis, nucleotide metabolism, and cutin–suberin–wax biosynthesis are the core responsive pathways. Correlation analysis revealed that isocorydine and phosphatidylinositol phosphate showed strong positive correlations with the vigor index, main root length, and superoxide dismutase (SOD) activity, and glycerophospholipid metabolites were positively correlated with ferric ion-reducing antioxidant capacity. (4) This study deepens understanding of the stress resistance mechanisms in forage peas and provides a theoretical basis for stress-resistant forage pea breeding. Full article

Drought poses a severe threat to grassland biodiversity and ecosystem function. However, quantitative frameworks that capture the interactive effects of drought intensity and duration on productivity remain scarce, limiting impact assessment accuracy. To bridge this gap, we developed and validated a novel hybrid modeling framework to quantify drought impacts on net primary productivity (NPP) across Inner Mongolia’s major grasslands (1961–2012). Drought was characterized using the Standardized Precipitation Index (SPI), and ecosystem productivity was simulated with the Biome-BGC model. Our core innovation is the hybrid model, which integrates linear and nonlinear components to explicitly capture the compounded, nonlinear influence of combined drought intensity and duration. This represents a significant advance over conventional single-perspective approaches. Key results demonstrate that the hybrid model substantially outperforms linear and nonlinear models alone, yielding highly significant regression equations for all grassland types (meadow, typical, desert; all p < 0.001). Independent validation confirmed its robustness and high predictive skill (NSE ≈ 0.868, RMSE = 20.09 gC/m²/yr). The analysis reveals two critical findings: (1) drought duration is a stronger driver of productivity decline than instantaneous intensity, and (2) desert grasslands are the most vulnerable, followed by typical and meadow grasslands. The hybrid model serves as a practical tool for estimating site-specific productivity loss, directly informing grassland management priorities, adaptive grazing strategies, and early-warning system design. Beyond immediate applications, this framework provides a transferable methodology for assessing drought-induced vulnerability in biodiverse ecosystems, supporting conservation and climate-adaptive management. Full article

Phenotypic plasticity is a key mechanism by which crops adjust to fluctuating environmental conditions, yet its genetic basis under drought remains poorly characterized in barley (Hordeum vulgare). We hypothesized that phenotypic plasticity under drought is controlled by a distinct, trait-specific genetic architecture that can be detected using complementary plasticity metrics and genome-wide association studies (GWAS). Here, we examined data from 1277 spring barley genotypes grown under well-watered and water-limited conditions to quantify plastic responses across two developmental traits (i.e., heading time, and maturity) and seven productivity-related traits (i.e., total dry matter, plant grain yield, grain number, grain weight, harvest index, vegetative dry weight, and grain-filling period). The experimental design, based on contrasting water regimes across a large diversity panel, allowed robust assessment of genotype-by-environment interactions. We combined five complementary plasticity estimators with four independent GWAS approaches to resolve the genomic architecture underlying trait-specific plasticity. Environmental effects dominated variation in yield-related traits, whereas developmental traits remained more genetically determined. The different plasticity metrics captured distinct but partially overlapping response dimensions, and their integration greatly increased the robustness of association signals. A total of 239 high-confidence SNPs obtained for top traits, those associated across metrics and methods, were enriched in coding regions and mapped to genes involved in osmoregulation, carbohydrate metabolism, hormonal pathways, and ion transport. A total of 27 high-confidence SNPs were located in coding regions, showing genotype-specific differences in the magnitude and even direction of phenotypic plasticity. These loci exhibited opposite allelic effects across water regimes, consistent with context-dependent antagonistic pleiotropy. The fact that candidate alleles for the plastic response modulate environmental sensitivity differently highlights that drought resilience arises from environment-contingent genetic architectures. Overall, these results provide a comprehensive framework for dissecting plasticity and identify concrete genomic targets for indirect selection targeting crop resilience with improved performance under increasingly variable water availability. Full article

In this study, we compare two contrasting years within the 2020–2025 period—one characterized by extreme heat and drought, and another by unusually high precipitation. We used five years of climatic data provided by the Hungarian Meteorological Service (OMSZ), along with vegetation activity indices (NDVI—Normalized Difference Vegetation Index; NDWI—Normalized Difference Water Index) derived from Sentinel-2A satellite imagery. In parallel, during three years of the study period (2020, 2022, and 2025), we collected five phytosociological relevés in each of the five vegetation types subjected to different management regimes. For data analysis, we applied Principal Component Analysis (PCA), Detrended Correspondence Analysis (DCA), and the Additive Main Effects and Multiplicative Interaction (AMMI) model. Vegetation index patterns were compared with the relative water requirements of the constituent plant species. In the ungrazed dry sandy site, climatic fluctuations did not significantly affect vegetation composition and the habitat remained a stable open sandy grassland. Among the four grazed sites, grazing intensity remained unchanged during the study in three cases (N1, N2, and SZ). Thus, vegetation changes observed in these areas can be attributed to climatic factors. Vegetation composition shifted in N1 and N2, whereas no significant change was detected in the drier SZ site. This indicates higher resistance to grazing in SZ, which can therefore be sustainably used as pasture, while the N1–N2 sites responded sensitively to precipitation variability under identical grazing pressure and are better suited for use as meadows. The most pronounced changes occurred at the P site, which had previously functioned as an animal resting area and began regenerating after abandonment in 2022. Vegetation composition shifted markedly within two years, demonstrating that land-use practices exert a stronger influence on sandy grassland vegetation than climatic fluctuations. Overall, the drier habitats were more resilient to both grazing pressure and climatic variability and are suitable for grazing, whereas the moister vegetation types were more sensitive and should preferably be managed as hay meadows. Full article

The increasing frequency and intensity of droughts, a direct consequence of climate change, represent one of the main threats to agriculture, especially for crops with a high water demand such as the processing tomato. The objective of this study is to evaluate the potential of the IrriDesK digital twin (DT) as a tool for automated irrigation management and the implementation of regulated deficit irrigation (RDI) strategies tailored to the crop’s water status and phenological stage. The trial was conducted in an experimental plot over two consecutive growing seasons (2023–2024), comparing three irrigation treatments: full irrigation based on lysimeter measurements (T1) and two RDI strategies programmed through IrriDesK (T2 and T3). The results showed water consumption reductions of 30–45% in treatments T2 and T3 compared to treatment T1, with applied volumes of 277–400 mm versus approximately 570 mm in treatment T1, thus remaining within the sustainability threshold (<500 mm, equivalent to 5000 m³ ha⁻¹). This threshold corresponds to the maximum seasonal allocation typically available for processing tomato under drought conditions in the region and was used to configure the DT’s seasonal irrigation plan. The monitoring of leaf water potential (Ψleaf) and the normalized difference vegetation index (NDVI) confirmed the DT’s ability to dynamically adjust irrigation and maintain an adequate water status during critical crop phases. In terms of productivity, treatment T1 achieved the highest yields (≈135 t ha⁻¹), while RDI strategies reduced production to 90–108 t ha⁻¹, but improved fruit quality, with increases in total soluble solids content of up to 10–15% (°Brix). These results demonstrate that IrriDesK is an effective tool for the optimization of water use while maintaining crop profitability and enhancing the resilience of processing tomatoes to drought scenarios. Full article

Climate change exacerbates soil moisture deficits, necessitating efficient water retention strategies. Superabsorbent polymers (SAPs) offer a potential solution to enhance water availability for crops during dry periods. Faba bean (Vicia faba L.) and pea (Pisum sativum L.) were selected as model legumes due to their high nutritional value, agricultural importance in temperate regions, and sensitivity to drought stress This study evaluated the effects of different SAP application rates on the yield and physiological performance of two legume species: faba bean (cv. Granit) and pea (cv. Batuta). The two-year (2017–2018) field experiments employed a randomized block design with four replicates. Treatments included three SAP doses: 0 (control, SAP0), 20 (SAP20) and 30 (SAP30) kg·ha⁻¹. The study was conducted over two years with contrasting weather: 2017 was wetter but had uneven rainfall distribution, while 2018 was drier and characterized by moisture deficits during critical growth stages. SAP application significantly increased seed yield in faba bean and pea, with the most favorable effect observed at 20 kg ha (average yield increase of 23.6% and 17.3%, respectively). SAP did not affect yield components in faba bean. However, in peas, an increase in pod number and seed number per plant was observed with the SAP30 dose compared to the SAP20 dose. Application of superabsorbent at a dose of 20 kg ha⁻¹ significantly increased photosynthesis rate in faba bean, the Fv/Fm index in the tested species, and the PI in peas compared to the control. However, the superabsorbent did not affect transpiration rate or the WUE coefficient in the tested legume species. Significantly higher yields in faba bean and pea and all tested plant structure parameters in pea were recorded in 2018 compared to 2017. The tested parameters of gas exchange and chlorophyll fluorescence were higher in pea in 2018 (except for transpiration intensity) and in faba bean in 2017. The findings suggest that SAPs can be a useful tool to mitigate water stress effects in legumes, although their effectiveness depends on environmental conditions. Therefore, SAP application may be a promising agronomic strategy in regions prone to irregular rainfall or moderate drought. Full article

Extended droughts are predicted for southwestern North America, including the arid Mojave Desert, which has plant communities dominated by desert scrub vegetation. We conducted a multi-year study in which supplemental water was provided to four native shrub species: the evergreen Larrea tridentata and deciduous Ambrosia dumosa, Ambrosia salsola, and Encelia farinosa. Water treatments included −25% of precipitation (by temporarily deploying large tarps over wooden support structures), actual precipitation, and 100% and 200% of actual precipitation. Water applied occurred within 24 h of actual precipitation events. At the end of a two-year period, we allowed the plots to remain intact, receiving no supplemental water for 3.8 years, which was anomalously dry. During the initial two-year experiment, we examined growth and other physiological responses to the treatments. We also measured soil volumetric water content with depth and calculated a plant water stress index. After the 3.8-year dry period we measured stem elongation, canopy volume, leaf xylem water potential and harvested roots and shoots for biomass estimates. Supplemental water led to higher soil water content and water use, leading to increased aspects of growth which were species dependent, whereas the −25% treatment resulted in greater stress and reduced growth, but only in some species. After the 3.8-year dry period, survival in all treatments was between 97 and 100%. However, a distinct legacy effect was observed, as plants growing under the wetter treatments during the 2-year supplemental water period had more negative leaf xylem water potentials after the 3.8-year dry period than plants that were grown under the drier treatments. In addition, canopy volumes were shown to decrease if plants were grown under the wetter treatment imposed during the supplemental water period but increased if grown under the drier treatments. Our results would suggest that the impact of climate change on Mojave Desert shrubs will be linked to how they respond to wet/dry cycles, which will be linked to drought severity and the time between wet periods. The four shrub species studied have unique morphological and physiological characteristics that allow them to grow and not just survive under arid conditions, but if extended drought events occur on a more frequent basis, these shrub species may not be able to adapt and thus avoid higher mortality rates. Full article

Mixed stands enhance climate resilience and ecosystem service provision through functional diversity, but their productivity depends on intra- and interspecific competition, forest structure, stand density, and site conditions. In this study, we analyzed the effects of competition and aridity on the growth of European beech (Fagus sylvatica L.) in mixed and pure stands, using data from 38 plots of the Italian National Forest Inventory (NFI, 2015). To understand the variables influencing European beech growth, tree-level basal area increment models were applied, incorporating different competition structures (intraspecific, interspecific, size-symmetric, and size-asymmetric) and aridity index (De Martonne). Results showed that size-asymmetric intraspecific competition negatively affected European beech growth, highlighting low self-tolerance, especially in pure stands where growth was lower than in mixed stands. In mixed stands, European beech growth was shaped by size-dependent competition and the relative dominance of coexisting species, benefiting from size-asymmetric and hindered by size-symmetric interactions. Additionally, European beech growth was shaped by aridity and stand structure (Gini coefficient and density), with drought sensitivity mitigated in mixed stands and enhanced growth in structurally diverse, low-density stands. This study highlights how species interactions, aridity, and stand structure jointly shape tree growth, underscoring their importance for climate-adaptive forest management. Full article

The Gravity Recovery and Climate Experiment (GRACE) tracks drought events by detecting changes in the global gravitational field and capturing abnormal information on the reserves of surface water, soil water, and groundwater, which makes it possible for a more comprehensive and unified global and regional monitoring of groundwater drought. This study adopted the gravity satellite GRACE data and combined it with the hydrological model dataset. Additionally, we assessed the temporal evolution and spatial pattern of groundwater drought in the Yangtze River Basin (YRB) and its sub-basins from 2003 to 2022, determined the change points of the hidden seasonal and trend components in groundwater drought, and identified the direct/indirect driving contributions of the main climatic and circulation factors to groundwater drought. The results show that (1) as a normalized index, the groundwater drought index (GDI) can reflect direct evidence of any surplus and deficit in groundwater availability. During the study period, the minimum value (−1.66) of the GDI occurred in July 2020 (severe drought). (2) The average value of GDI in the entire basin ranged from −1.66 (severe drought) to 0.52 (no drought). (3) The average Z_s values (Mann–Kendall Z-statistic) of GDI were −0.23, −0.16, −0.43, and 0.14, respectively, and the proportions of areas with aggravated drought reached 65.21%, 61.05%, 89.70% and 43.67%, respectively. (4) Partial wavelet coherence analysis can simultaneously reveal the local correlations of time series at different time scales and frequencies. Based on partial wavelet analysis, precipitation was the best factor for explaining the dynamic changes in groundwater drought. (5) The North Pacific Index (NPI), the Pacific/North American Index (PNA), and the Sunspot Index (SSI) can serve as the main predictors that can effectively capture the drought changes in groundwater in the YRB. The GRACE satellite can provide a new tool for monitoring, tracking, and assessing groundwater drought situations, which is of great significance for guiding the development of the drought early warning system in the YRB and effectively preventing and responding to drought disasters. Full article