Search Results (1,213)

The aim of study was to investigate the effects of foliar application of salicylic acid on cellular damage, physiological indices, and growth of dwarf cashew cultivated under salt stress. A 5 × 4 factorial scheme, resulting from the combination of five ECiw levels (0.4, 1.2, 2.0, 2.8, and 3.6 dS m⁻¹) and four salicylic acid concentrations (control—0, 1, 2, and 3 mM), with three replications. Irrigation water salinity of 3.6 dS m⁻¹ inhibited the synthesis of photosynthetic pigments, gas exchange, chlorophyll a fluorescence, and the growth of dwarf cashew plants. Foliar application of salicylic acid at concentrations ranging from 0.1 to 2.5 mM mitigated the effects of salt stress on relative water content, stomatal conductance, internal CO₂ concentration, CO₂ assimilation rate, instantaneous carboxylation efficiency, variable fluorescence, quantum efficiency of photosystem II, stem diameter at the grafting point, and plant height, while also reducing electrolyte leakage and initial fluorescence in dwarf cashew plants at 180 days after transplanting. Salicylic acid (SA), when applied at appropriate concentrations, alleviates the deleterious effects of salt stress on the growth and physiological performance of dwarf cashew plants. Full article

Sweet sorghum is a promising crop for bioethanol production in semi-arid regions, due to its tolerance to drought and salinity, where conventional energy crops face limitations. This study aimed to evaluate the agronomic performance of sweet sorghum irrigated with treated domestic wastewater (TDW) and its application as a substrate for bioethanol production under high-gravity (HG) and very-high-gravity (VHG) fermentation conditions. Field experiments were conducted in the Brazilian semi-arid using a 5 × 5 full factorial design consisting of five irrigation depths (40–160% crop evapotranspiration, ETc) combined with five potassium fertilization doses (0–80 kg·ha⁻¹), totaling 25 treatments. Agronomic performance, biomass production, and total reducing sugar accumulation were evaluated in both plant cane and ratoon crops. Sweet sorghum juice was subsequently combined with sugarcane molasses and fermented using Saccharomyces cerevisiae in batch and fed-batch processes. Irrigation with TDW associated with moderate potassium fertilization enhanced plant development, biomass yield, and sugar accumulation, particularly at irrigation depths between 100% and 130% of ETc, reaching up to 1908 kg·ha⁻¹ of TRS. Bioethanol production achieved fermentation efficiencies of 91.83% and 84.80% and productivities of 4.63 and 4.21 g·L⁻¹·h⁻¹ under HG and VHG conditions, respectively. These findings indicate that sweet sorghum irrigated with TDW is a promising feedstock for bioethanol production under high-gravity fermentation conditions while supporting the use of alternative water resources in semi-arid environments. Full article

Calcium alginate is an anionic polysaccharide that forms an ionically crosslinked hydrogel network with encapsulation properties to nucleic acids and nutrients for the amelioration of osmotic stress, ion toxicity and nutrient imbalance in saline–alkali soils. Traditional soil reclamation methods, including salt leaching, incorporation of organic matter, and gypsum application, are water-intensive under a changing climate, ultimately necessitating transformative bio-based solutions for food security. Calcium alginate-based biohydrogel represents a versatile platform with a tunable macromolecular architecture, ionic crosslinking via an “egg box” mechanism and potentially promising to deliver engineered co-encapsulated nutrients and genetically modified cargoes. The mannuronic (M) and guluronic (G) acid (M/G) ratios govern ion exchange capacity, rheological behavior and release kinetics in saline- and alkali-stressed environments. Recent studies on alginate-based nutrient encapsulation showed reduced oxidative damage and a 15–50% increase in plant-available water. The irrigation intervals extended from 7 to 14 days and yield gains by 24% in wheat, with comparable improvements in maize, tomato, rice and cotton. Calcium alginate hydrogels encapsulated salt tolerance genes (HKT1, SOS1, AVP1) encoding proteins mainly involved in Na⁺ retrieval from xylem, Na⁺ extrusion from root cells and vacuolar Na⁺ sequestration, which have achieved yield gains of 40 to 75% across wheat, rice and maize. Future research should focus on optimizing mechanical strength, crosslinking chemistry and smart bioencapsulation strategies for sustainable development so that crops are capable of withstanding variable climate stresses. Full article

Groundwater quality in arid and semi-arid regions is increasingly affected by salinization, evaporation, abstraction, and agricultural return flow. This study evaluates the hydrochemical evolution, isotopic characteristics, ²²²Rn activity, and water-use suitability of groundwater and associated waters in Karbala Governorate, central Iraq. Seventeen groundwater, lake water, and municipal supply water samples were analyzed for physicochemical parameters, major ions, δ¹⁸O, δ²H, and ²²²Rn. Hydrochemical, isotopic, and water-quality assessment methods were applied to evaluate groundwater evolution, salinization, and suitability for drinking and irrigation. The waters are near-neutral, with pH values of 6.18–7.35, but are strongly mineralized. Electrical conductivity ranges from 1440 to 16,305 µS/cm, and total dissolved solids (TDS) range from 592 to 10,191 mg/L. Most samples belong to a Ca–Mg–SO₄–Cl facies, indicating sulfate- and chloride-rich hard water evolution. The highest mineralization occurs near Karbala proper and lake-influenced sites. Ion ratios and chloro-alkaline indices indicate that evaporite dissolution, gypsum/anhydrite dissolution, carbonate interaction, evaporation, and local ion exchange jointly control groundwater chemistry. Stable isotopes indicate meteoric origin with variable evaporative enrichment; however, highly saline but isotopically depleted water, particularly W8, shows that evaporation alone cannot explain salinization. ²²²Rn activities range from below detection to 11.28 Bq/L and mainly reflect local aquifer contact and degassing. High TDS, sulfate, chloride, and very high hardness limit suitability for drinking-water use. For irrigation, the sodium hazard is low, but salinity, hardness, magnesium hazard, and permeability constraints make most samples unsuitable or restricted. Management should prioritize salinity and hardness control, treatment or blending before domestic use, restricted irrigation of the least saline wells under drainage and soil-salinity monitoring, protection of less mineralized recharge zones, and long-term monitoring of lake-adjacent and agriculturally influenced wells. Full article

Global population growth and numerous anthropogenic activities are putting increasing pressure on island aquifers. This situation is exacerbated in popular tourist destinations where seasonal population fluctuations increase water consumption. Most island aquifers are threatened by overexploitation, contamination, and seawater intrusion (SWI), which threaten these resources’ sustainability. In this study, the vulnerability of the Bozcaada Island (Türkiye) to SWI during peak seasons (summer) was assessed using the GALDIT approach. The GALDIT index takes into account six key hydrogeological characteristics, including groundwater occurrence (G), which represents the type of aquifer (confined, unconfined, or semi-confined) and influences the interface between freshwater and saline water; aquifer hydraulic conductivity (A), where higher conductivity increases the risk of SWI and determines how easily water flows; groundwater level above mean sea level (L), which indicates hydraulic pressure against SWI; distance from the coast (D), which implies higher SWI risk when close to the coast; existing intrusion status (I), which takes into account current SWI detections based on the ratio of chloride ions to bicarbonate ions in a groundwater sample; and aquifer thickness (T). Bozcaada Island hosts a large number of tourists during the summer months, when agricultural production is at its peak, with a high demand for irrigation. This significantly increases the demand for groundwater and leads to saltwater intrusion. Based on the results of the GALDIT index, the island’s groundwater reserves are heavily used throughout the summer. The GALDIT index for the summer shows that this increased groundwater abstraction intensifies the SWI problem. In summer, the island is vulnerable with 6.11 km² of extremely high SWI, 7.88 km² of high SWI, 7.34 km² of moderate SWI, 7.40 km² of low SWI and 8.50 km² of very low SWI. This study emphasizes how urgently Bozcaada Island needs sustainable water management techniques. Full article

As one of the most economically important cucurbit crops, melon (Cucumis melo L.) is extensively cultivated in semi-arid and tropical regions where high evaporative demand frequently intensifies salt accumulation. These conditions promote the evaporative concentration of salt, leading to salt accumulation in soil and irrigation water, which can impair crop development. Therefore, identifying approaches capable of maintaining seedling establishment under saline conditions is crucial for sustainable melon production. This study evaluated tolerance and antioxidant responses in different melon cultivars using seed treatments to mitigate salt stress effects. The experiment was conducted in two stages under a completely randomized design with four replicates of 50 seeds. In the first stage, a 3 × 5 factorial design tested three salinity levels (0, 60, and 120 mM NaCl) and five cultivars (‘Dali’, ‘Premier’, ‘Supreme’, ‘Imperial 45’, and ‘Asturia’), assessing morphological, physiological, and biochemical traits. In the second stage, two contrasting cultivars (‘Imperial 45’ (sensitive) and ‘Asturia’ (tolerant)) were exposed to salinity combined with stress attenuators, including hydropriming, gibberellic acid, ascorbic acid, salicylic acid, and hydrogen peroxide. Additional biochemical markers and antioxidant enzyme activities were analyzed. Results showed that gibberellic acid and ascorbic acid enhanced antioxidant activity and reduced oxidative damage, particularly in Imperial 45, whereas hydrogen peroxide was more effective in Asturia. Based on their physiological and biochemical responses during germination and early seedling development, Asturia and Imperial 45 were identified as tolerant and sensitive to salt stress, respectively. These findings indicate that the effectiveness of seed treatments depends on cultivar-specific physiological characteristics at the seedling stage. Full article

To evaluate the effects of saline water on the yield and quality of tomatoes, a late fruit-setting stage irrigation experiment was conducted in a greenhouse using two cultivars: medium-fruited, tasty Strawberry tomato (fresh-eating) and large-fruited Maofen tomato (fresh/processing). For this, plants were grown in pots containing substrate, and five irrigation water electrical conductivity (EC) levels (1.0 as control, 2.6, 4.2, 5.8, and 7.4 dS m⁻¹) were applied for each cultivar, resulting in a 2 × 5 factorial design with 10 treatments in total. Then, tomato growth, fruit ion composition, and quality attributes were evaluated. The results showed that 1.0–7.4 dS m⁻¹ saline water had no significant impact on the plant height, stem diameter, single-fruit weight, or total yield of either cultivar. However, Strawberry tomato’s marketable yield decreased by 23.5% at 7.4 dS m⁻¹. The yield per plant of Maofen tomato was 2.7 times that of Strawberry tomato. Fruit Na⁺ content increased with EC for both cultivars; Maofen tomato had higher Na⁺ and a lower K⁺/Na⁺ ratio, with greater ion content responses to salinity. Regression analysis revealed distinctly nonlinear responses in key yield, ion, and quality parameters across the salinity gradient. The fruit comprehensive quality score (CQS) rose with EC, and Strawberry tomato’s average CQS increase (109%) was significantly higher than Maofen tomato’s. In conclusion, saline irrigation initiated when the fourth-cluster fruits attained 60% of the final harvested diameter, at EC ≤ 5.8 dS m⁻¹ for Strawberry tomato and ≤7.4 dS m⁻¹ for Maofen tomato, improved fruit quality without compromising yield. Strawberry tomato is recommended for quality-oriented production, whereas Maofen tomato is better suited for yield-oriented production, providing scientific support for saline water utilization in greenhouse soil-less cultivation. Full article

Purple basil (Ocimum basilicum L.) is a medicinal plant widely recognized for its richness in bioactive compounds; however, its production in semi-arid regions is often constrained by soil and/or irrigation water salinity. Micronutrient fertilization may contribute to plant stress alleviation under salinity, since elements such as Mn, Mo, and Zn are involved in essential processes related to photosynthetic metabolism and physiological adjustment. This study aimed to evaluate the short-term effects of Mn, Mo, Zn, and their combinations on growth, gas exchange, and relative chlorophyll indices of purple basil plants subjected to severe NaCl stress under greenhouse conditions. The experiment was conducted under greenhouse conditions for 30 days in a randomized block design with nine treatments and four replicates: a non-saline control without micronutrients, a saline control without micronutrients, and plants exposed to 100 mM NaCl with substrate application of Mn, Mo, Zn, MoMn, ZnMo, ZnMn, or ZnMoMn. Micronutrient sources were applied to the substrate at 3.5 g kg⁻¹ according to each treatment. Fertilization with Mn, Mo, Zn, and their combinations enhanced plant stress alleviation under salinity compared with the saline control without micronutrients, with positive responses in growth and physiological performance, including increases in chlorophyll indices. The double combinations MoMn, ZnMo, and ZnMn attenuated the effects of NaCl, especially by increasing leaf area. Mn stood out for increasing net photosynthesis and water-use efficiency, whereas Mo and ZnMo were associated with higher relative chlorophyll indices. Although the triple combination ZnMoMn improved some traits compared with the saline control, its lower efficacy relative to selected single or double applications may indicate that the simultaneous supply of the three elements reduced specific synergistic effects, possibly due to nutritional imbalance or antagonistic interactions among micronutrients under severe salinity. Overall, micronutrient fertilization, particularly through specific double combinations, may contribute to short-term mitigation of NaCl-induced stress responses under controlled greenhouse conditions. Full article

Saline irrigation is a major constraint to crop production in newly reclaimed desert lands, even when pre-sowing soil salinity is low. This two-season field study evaluated whether plant growth-promoting rhizobacteria could improve barley performance under saline irrigation water with an electrical conductivity of 11.8 dS m⁻¹ in the El Moghra region, Egypt. The barley cultivar Giza 2000 was grown under five inoculation treatments: an uninoculated saline-irrigated control; a single inoculation with Azospirillum lipoferum; and combined inoculations with A. lipoferum and Bacillus coagulans, Bacillus circulans, or Enterobacter cloacae. Because freshwater was unavailable at the experimental site, treatment effects were evaluated relative to the saline-irrigated control. Across both growing seasons, single inoculation with A. lipoferum produced the most consistent improvements in growth, yield formation, nutrient accumulation, soil biological activity, and seed nutritional quality. The combined treatment of A. lipoferum and B. circulans was generally the second-most effective. Bacterial inoculation also improved adjustment to physiological stress, as indicated by greater proline accumulation, lower antioxidant enzyme activities, and enhanced expression of stress-related genes associated with proline biosynthesis and secondary metabolism. Overall, the results indicate that A. lipoferum applied alone was more effective than the tested combinations of bacteria under saline irrigation. These findings provide field-based evidence that inoculant performance depends on strain composition and that single-strain inoculation can be a promising strategy for improving barley production in reclaimed sandy soils irrigated with saline water. Full article

Saline irrigation is increasingly practiced in semi-arid regions to cope with freshwater scarcity; however, it strongly affects crop growth, water use, and soil salinity. This study aims to calibrate and validate the AquaCrop model to simulate key growth parameters of winter wheat (cv. Achtar) under saline irrigation conditions in the Tadla Plain, Morocco, focusing on canopy cover (CC), actual evapotranspiration (ETa), soil water content (SWC), biomass (B), and grain yield (GY). The model was first calibrated using observed data from the 2023 growing season and subsequently validated using data from the 2022 growing season. Overall, AquaCrop effectively reproduced crop growth during both calibration and validation phases. During calibration, canopy cover was accurately simulated, with average RMSE values below 1%, while biomass and grain yield were also well reproduced, with low RMSE values (0.25 t ha⁻¹ for B and 0.10 t ha⁻¹ for GY), confirming the robustness of the calibrated parameters. The model also performed well in simulating ETa and SWC, capturing the seasonal dynamics of crop water use and soil moisture. During validation, ETa was satisfactorily reproduced, with an RMSE of approximately 0.80 mm day⁻¹, while SWC showed good agreement with observations, with NRMSE values ranging from 7.9 to 10.5%. Grain yield and biomass were reliably predicted, with NRMSE values below 4%. These results demonstrate that AquaCrop is a reliable tool for simulating winter wheat under saline irrigation and for assessing crop response under salt-affected conditions, providing an integrated evaluation of crop performance, water use, and soil salinity dynamics to support improved irrigation management and water-use efficiency under semi-arid conditions. Full article

This study assesses the phytoremediation potential and biomass production of sweet sorghum (Sorghum bicolor L.) and switchgrass (Panicum virgatum L.) under saline field conditions in 2024 and 2025. Salinity was defined based on electrical conductivity (EC), and phytoremediation performance was evaluated in this study. Sweet sorghum consistently produced high biomass (56.700–78.600 kg/ha), yet saline irrigation decreased its yield by 6% in 2024 and 11% in 2025, alongside a 19% reduction in plant height in 2025. Conversely, saline irrigation promoted switchgrass growth, increasing biomass yield from 2548 to 3643 kg ha⁻¹ (43%) in 2024 and from 4503 to 5812 kg ha⁻¹ (29%) in 2025. Plant height also increased by up to 35% in 2025 under saline conditions. In this study, when the Na⁺ (me/L) results at 10 cm of irrigated soil under saline conditions were examined, sorghum and switchgrass plants produced statistically significant differences in their saline-irrigated plots compared to their plots irrigated with non-saline water. In contrast, no significant differences were observed between sorghum and switchgrass in terms of soil Na removal under either saline or non-saline irrigation conditions. Therefore, both plants have a similar sodium reduction capacity. Full article

This study aimed to determine the optimal biochar application rate for sustaining cotton productivity in moderately saline soils under dry sowing with wet emergence (DSWE) conditions in Shaya County, Xinjiang. A two-year field experiment, arranged in a randomized complete block design with two replicates, evaluated six biochar application rates (S1–S6) against a non-amended control (CK). The biochar, derived from fruit-wood via limited-oxygen pyrolysis at 500 °C (pH 9.82, porosity 64.5%), was applied as a single pre-sowing amendment. Soil water–salt dynamics, crop emergence, and growth parameters were continuously monitored. The results indicated that biochar application consistently reduced soil salinity; specifically, seedling-stage salinity decreased by 30.1–42.2% in the first year compared with the CK. Cotton emergence and yield improved significantly across both seasons. However, the optimal application rate for maximizing yield varied between years. While a high rate (S5: 25 t·hm⁻²) produced the highest first-year yield (6243.8 kg·hm⁻²), a moderate rate (S3: 15 t·hm⁻²) demonstrated greater yield stability and achieved the maximum yield (5975.2 kg·hm⁻²) in the second year. This interannual shift is likely attributable to biochar aging and structural pore saturation in the high-dose plots. Combined with high regional evaporation, these factors exacerbated secondary salinization and reduced the residual benefits of the amendment over time. In contrast, the moderate dose maintained a more effective balance between continuous water–salt regulation and nutrient availability. Under the experimental conditions, a single pre-sowing application of 15 t·hm⁻² biochar, combined with a 375 m³·hm⁻² drip irrigation volume, is recommended as an effective strategy to ameliorate salinity and support long-term yield stability. Full article

Efficient irrigation management requires reliable information on soil water content, yet low-cost capacitive sensors often lack proper calibration. This study evaluates the metrological performance of two DF Robot probes, SEN0193 (S1) and SEN0308 (S3), under controlled variations in porous media properties. Glass beads of three size classes (<50 µm, 70–110 µm, and 400–600 µm) were used to simulate fine, medium, and coarse textures. Sensors were tested at four water contents (0, 10, 20, and 30%) and four salinity levels (0, 4, 8, and 16 g NaCl L⁻¹). Results show that the manufacturer-recommended air/water calibration is unsuitable for soils or porous media; calibration should instead be performed under dry and saturated conditions specific to the medium. S1 exhibited stable and homogeneous responses, with intra-unit CV ≤ 2%, but moderate calibration accuracy (R² = 0.68–0.80; RMSE = 8.9–12.9% VWC across textures). S3 showed a wider signal range (80–90% larger than S1), better fit in coarse texture (R² = 0.96; RMSE = 3.5% VWC), but higher unit-to-unit variability (CV = 6–14%) and performance degradation in fine and saline media. Although these sensors cannot provide accurate absolute quantification, their ability to track moisture trends makes them useful for irrigation management, provided calibration accounts for medium texture and salinity. Full article

Soil salinity and alkalinity are major constraints to agricultural productivity in arid regions, particularly where treated wastewater (TWW) is used for irrigation. This study evaluated the spatial variability of water and soil physicochemical properties along Wadi Hanifa, Saudi Arabia, and compared soils from two farms irrigated with TWW for approximately 5 and 15 years to assess the effects of irrigation duration on soil properties. Soil samples were collected from 25 locations along the Wadi using a handheld Global Positioning System (GPS), and water and soil properties were analyzed using standard laboratory procedures. The treated wastewater exhibited moderate electrical conductivity (EC = 2.0 dS m⁻¹) and low sodicity hazard (SAR = 1.55), indicating its suitability for irrigation under appropriate management practices. Soils were predominantly coarse-textured and showed considerable spatial variability in salinity and chemical composition. Soil pH remained relatively stable (7.33–8.07), while EC ranged from 0.88 to 2.64 dS m⁻¹, indicating non-saline to moderately saline conditions across the study area. Comparison of soil profiles from the two farms revealed greater salinity in subsurface layers, particularly at the farm irrigated with TWW for 15 years, where EC reached 4.15 dS m⁻¹ and Na⁺ concentrations reached 16.4 meq L⁻¹. These observations suggest salt redistribution and accumulation within deeper soil horizons under prolonged irrigation. Overall, soil and water quality in Wadi Hanifa are strongly influenced by spatial variability, coarse soil texture, and arid climatic conditions. The findings highlight the importance of regular monitoring of salinity and sodicity indicators, together with adequate leaching and drainage practices, to ensure the sustainable use of treated wastewater for agricultural production in arid environments. Full article

To meet the demand for superabsorbent, long-acting water-retentive, and recyclable hydrogel materials in landscaping applications, a series of AG-PAA/DA composite hydrogels were prepared using agarose (AG) and polyacrylic acid (PAA) as the network backbone, incorporating different mass fractions (2–30%) of dopamine (DA) via free radical polymerization initiated by ultraviolet light. The effects of DA content on the chemical structure, morphology, thermal stability, mechanical properties, water retention behavior, swelling kinetics, and cyclic water absorption–desorption performance were systematically investigated. The results show that DA is successfully integrated into the AG-PAA network through hydrogen bonding, electrostatic interactions, and covalent crosslinking, forming an amorphous homogeneous system. Thermal stability increases with DA content (residual mass at 800 °C rises from 77% to 88%). Mechanical properties exhibit a trend of increasing stress but decreasing strain, with optimal toughness (~670 kJ/m³) achieved at 10 wt% DA. Water retention performance is environment-dependent: in pure water, water retention increases with higher DA content, whereas in soil the opposite trend is observed. The kinetics of swelling conform to the pseudo-second-order model. The hydrogel with 10 wt% DA exhibits an equilibrium water absorption of 50 g/g in 0.9% saline solution and 1060 g/g in deionized water, and after 20 swelling–deswelling cycles the capacity retention fluctuates by less than 5%, demonstrating excellent cyclic stability. Considering all properties, AG-PAA/DA-10 is identified as the optimal formulation. This hydrogel combines high water absorption capacity, good environmental adaptability, and recyclability, showing great promise for water-saving irrigation in landscaping. Full article