Search Results (2,782)

Using reclaimed water for irrigation is an effective strategy in semi-arid regions facing water scarcity. However, this water may contain pharmaceutical residues, posing potential environmental and health risks. To ensure sustainable reuse, it is essential to study how these substances accumulate in soil and transfer to crops. The aim of this research was to develop and optimise a rapid Ultrasound-Assisted Extraction method combined with Ultra-High-Performance Liquid Chromatography–tandem Mass Spectrometry for quantifying 23 pharmaceuticals in non-cultivated soil. Following optimisation, 18 compounds were successfully extracted using a MeOH:H₂O ratio of 75:25. The detection and quantification limits were found to range from 0.52 to 0.5 ng·g⁻¹ and 1.75 to 35 ng·g⁻¹, respectively. The matrix effects and recoveries varied by compounds’ type and concentration, but most results were acceptable. The evidence suggested that some drugs underwent microbial degradation. Soil irrigated with reclaimed water via subsurface drip since 2012 occasionally contained four pharmaceuticals (caffeine, carbamazepine, tamoxifen, and venlafaxine) at low concentrations, while others were absent. This indicates the capacity of soil to act as a barrier, and highlights the importance of proper water management. The study concludes that reclaimed water reuse is safe if supported by efficient treatment and management, offering a promising approach for long-term sustainability in water-scarce regions. Full article

Cold stress impairs crop productivity through cascading inhibition of root growth, nitrogen (N) metabolism, and photosynthesis, yet the systematic linkages among these physiological disruptions remain poorly understood. It is crucial to elucidate the mechanisms by which cold-tolerant varieties maintain root growth and N-metabolizing enzyme homeostasis. This two-year field study investigated how cold duration at the tillering stage impacted root traits, N metabolism, photosynthesis, and their relationships with the yield of two japonica rice varieties differing in cold tolerance. A cold-tolerant (Dongnong 428) and a cold-sensitive variety (Songjing 10) were grown in a paddy field for two consecutive growing seasons in 2021 and 2022. Cold water (15 °C) was irrigated for 0 (denoted as D0), 5 (D5), 10 (D10), and 15 days (D15) during the tillering stage. Compared to D0, cold-water treatments significantly reduced root traits and total dry weight of both varieties. Cold stress significantly impaired N metabolism and photosynthesis, leading to significant reductions in N efficiency. The magnitude of these changes turned to greater with cold-water treatment duration. Dongnong 428 showed stronger cold tolerance, attributed to its maintenance of superior root traits and photosynthetic performance, as well as higher activities of enzymes in the roots, which sustained N assimilation and utilization. These factors primarily contributed to Dongnong 428 achieving 11.6–20.9% higher yields compared to Songjing 10. Cold stress during the tillering stage disrupts root growth and photosynthesis, impairs plant N acquisition ability, resulting in substantial yield loss. Cold-tolerant varieties maintain superior root morphology/functionality and photosynthetic performance. Full article

With the advancement of modern agriculture and increasing scarcity of water and fertilizer resources, determining optimal water and nitrogen (N) management strategies for intercropping systems is critical for ensuring system productivity and enhancing resource-use efficiency. This study employed field experiments to investigate the effects of different water and N treatments on grain yield, aboveground biomass, leaf area index (LAI), photosynthetic parameters, chlorophyll fluorescence characteristics, and radiation use efficiency (RUE) in a maize–soybean intercropping system. The experiment consisted of three cropping systems (maize monoculture, soybean monoculture, and maize–soybean intercropping), two irrigation regimes (rain-fed and supplemental irrigation), and three N-application rates for maize (240, 180, and 120 kgN ha⁻¹). The results demonstrated that supplementary irrigation significantly enhanced the LAI and photosynthetic capacity of both maize and soybean during critical growth stages, thereby promoting increases in grain yield and aboveground biomass. Intercropping significantly improved the productivity and photosynthetic performance of maize compared to monoculture, whereas soybean exhibited a reduction under intercropping conditions. Furthermore, irrigation regime and N rate had significant interactive effects on the photosynthetic performance of maize at the tasseling stage. In the intercropping system, a 25% reduction in the conventional application rate of N for maize maintained system productivity, whereas a 50% reduction substantially decreased maize yield and photosynthetic performance. The intercropping system achieved land equivalent ratios (LERs) ranging from 1.06 to 1.11 and RUE advantages (ΔRUE) of 1.52 to 1.64, demonstrating significant superiority in land and light resource utilization. Considering both productivity and resource-use efficiency, supplemental irrigation combined with 180 kgN ha⁻¹ N application for maize represents the optimal water and N management strategy for achieving high yield and efficiency in maize–soybean intercropping systems in the Guanzhong plain. Full article

Oxyfertigation with hydrogen peroxide (H₂O₂) has been successfully applied in several crops and production systems, but its use in mature citrus orchards under no-tillage conditions and semi-arid Mediterranean environments remains scarcely studied. This study aimed to evaluate the physiological responses of adult citrus trees and the agronomic performance of a mature citrus orchard subjected to chemical oxyfertigation based on the application of H₂O₂ in irrigation water as an oxygen source for the root zone. The experiment was conducted over four consecutive seasons (2018–2021) on adult ‘Ortanique’ hybrid mandarin trees grown in an orchard located in Torre Pacheco (Murcia, Spain). Two treatments were established: a ‘Control’ (0 mg L⁻¹ of H₂O₂) and an ‘OXY’ treatment (50–100 mg L⁻¹ of H₂O₂ applied throughout the growing season). Oxyfertigation significantly increased the dissolved oxygen in irrigation water and soil oxygen diffusion rate, with treatment and treatment × time effects showing greater oxygenation under conditions favoring transient root-zone hypoxia. Soil CO₂ and H₂O vapor fluxes exhibited marked seasonal dynamics but no consistent treatment effect, and soil salinity and macro- and micronutrient contents were not significantly altered. At the plant level, oxyfertigation episodically enhanced leaf gas exchange and transiently improved the water status, but did not produce a sustained increase in leaf-level water use efficiency. In contrast, OXY trees showed greater pruning biomass, more fruits (+18%), higher cumulative yield (+13%), and significantly higher crop water use efficiency (YWUE) while the mean fruit weight and most quality attributes were governed by interannual climatic variability. In summary, oxyfertigation acted as a complementary and safe agronomic practice that improved rhizosphere oxygenation and supported modest gains in fruit load and YWUE in mature citrus orchards. Full article

Polyacrylamide (PAM), a water-soluble polymer, is revolutionizing horticulture by improving water use efficiency and soil health, particularly in Pakistan’s water-scarce regions, offering a transformative solution. It reduces irrigation frequency by 30–40%, saving up to 50% of water while boosting crop yield by 20–50%. This results in a net profit increase of 30–60%, depending on the crop and soil type. Global studies show that PAM reduces soil erosion by 90–95% in furrow irrigation systems and increases water infiltration by 15–30%. Its hydrophilic properties enhance soil water-holding capacity by up to 400% compared to untreated soil, enabling plants to thrive in arid and semi-arid regions. Economically, the adoption of PAM is cost-effective. PAM also supports sustainable agriculture by mitigating the effects of water scarcity. These characteristics are in line with the objective of Pakistan to achieve agricultural sustainability and productivity. In conclusion, polyacrylamide is a feasible solution to address the water shortage in Pakistan and soil erosion, as well as to provide a significant amount of economic and environmental gains to the horticulture industry. The wide adoption of the technology could be triggered by pilot projects, farmer training, and government subsidies, which would change the agricultural landscape in the country. 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

Surface soil moisture (SSM) is essential for crop growth, irrigation management, and drought monitoring. However, conventional field-based measurements offer limited spatial and temporal coverage, making it difficult to capture environmental variability at scale. This study introduces a multimodal soil moisture estimation framework that combines synthetic aperture radar (SAR), optical imagery, vegetation indices, digital elevation models (DEM), meteorological data, and spatio-temporal metadata. To strengthen model performance and adaptability, an intermediate fine-tuning strategy is applied to two datasets comprising 10,571 images and 3772 samples. This approach improves generalization and transferability across regions. The framework is evaluated across diverse agro-ecological zones, including farmlands, alpine grasslands, and environmentally fragile areas, and benchmarked against single-modality methods. Results with RMSE 4.5834% and $R^2$ 0.8956 show consistently high accuracy and stability, enabling the production of reliable field-scale soil moisture maps. By addressing the spatial and temporal challenges of soil monitoring, this framework provides essential information for precision irrigation. It supports site-specific water management, promotes efficient water use, and enhances drought resilience at both farm and regional scales. Full article

In the Hetao Irrigation District of China, land consolidation to expand cultivated areas has disrupted the regional water–salt balance, increasing soil salinization risks. This study investigates the spatial optimization of cultivated land and salt-accumulating wasteland, using the SahysMod model to simulate soil water–salt dynamics and develop multi-scenario plans. The objective is to identify optimal strategies for regulating the dry drainage system and controlling salt accumulation by optimizing three key parameters: cultivated land-to-wasteland area ratio, elevation difference between cultivated land and wasteland, and spatial layout schemes. The results show that the SahysMod model accurately simulates soil water–salt interactions. Under the current scenario, the root zone ECe of cultivated land is projected to reach 6.16 dS·m⁻¹ by 2030, surpassing the salt tolerance threshold for sunflowers and threatening crop yield. The optimized scenario, which reduces the cultivated land-to-wasteland ratio from 14.41 to 12.97, increases wasteland area to 22.01 hm² and raises the elevation difference from 20 cm to 40 cm, significantly improving salt accumulation efficiency. By 2030, the ECe in the root zone decreases to 5.37 dS·m⁻¹, bringing soil conditions within the tolerance range for major crops in the region. Between 2021 and 2025, salt accumulation in cultivated land decreases dramatically from 19.08% to 5.60% under the optimized scenario, demonstrating effective early-stage salt control. However, from 2026 to 2030, the annual salt accumulation rate stabilizes at 24.88% (optimized) versus 25.20% (current), with a difference of only 0.32%. This finding reveals that while spatial optimization effectively mitigates short-term salt buildup, it has limited efficacy in preventing long-term salt accumulation. Spatial simulations suggest that a northern concentrated and southern patchwork wasteland layout enhances salt-accumulating capacity. These results demonstrate that spatial optimization of cultivated land and wasteland configuration alone is insufficient to fundamentally resolve soil salinization. Therefore, comprehensive measures, including drainage system improvements, soil amendments, and refined irrigation management, are necessary for sustainable salt management in arid irrigation regions. Full article

Globally, lakes are increasingly recognized as sensitive indicators of climate change and ecosystem stress. Qaraoun Lake, Lebanon’s largest artificial reservoir, is a critical resource for irrigation, hydropower generation, and domestic water supply. Over the past 25 years, satellite remote sensing has enabled consistent monitoring of its hydrological and environmental dynamics. This study leverages the advanced cloud-based processing capabilities of Google Earth Engine (GEE) to analyze over 180 cloud-free scenes from Landsat 7 (Enhanced Thematic Mapper Plus) (ETM+) from 2000 to present, Landsat 8 Operational Land Imager and Thermal Infrared Sensor (OLI/TIRS) from 2013 to present, and Landsat 9 OLI-2/TIRS-2 from 2021 to present, quantifying changes in lake surface area, water volume, and pollution levels. Water extent was delineated using the Modified Normalized Difference Water Index (MNDWI), enhanced through pansharpening to improve spatial resolution from 30 m to 15 m. Water quality was evaluated using a composite pollution index that integrates three spectral indicators—the Normalized Difference Chlorophyll Index (NDCI), the Floating Algae Index (FAI), and a normalized Shortwave Infrared (SWIR) band—which serves as a proxy for turbidity and organic matter. This index was further standardized against a conservative Normalized Difference Vegetation Index (NDVI) threshold to reduce vegetation interference. The resulting index ranges from near-zero (minimal pollution) to values exceeding 1.0 (severe pollution), with higher values indicating elevated chlorophyll concentrations, surface reflectance anomalies, and suspended particulate matter. Results indicate a significant decline in mean annual water volume, from a peak of 174.07 million m³ in 2003 to a low of 106.62 million m³ in 2025 (until mid-November). Concurrently, pollution levels increased markedly, with the average index rising from 0.0028 in 2000 to a peak of 0.2465 in 2024. Episodic spikes exceeding 1.0 were detected in 2005, 2016, and 2024, corresponding to documented contamination events. These findings were validated against multiple institutional and international reports, confirming the reliability and efficiency of the GEE-based methodology. Time-series visualizations generated through GEE underscore a dual deterioration, both hydrological and qualitative, highlighting the lake’s growing vulnerability to anthropogenic pressures and climate variability. The study emphasizes the urgent need for integrated watershed management, pollution control measures, and long-term environmental monitoring to safeguard Lebanon’s water security and ecological resilience. Full article

Cashew (Anacardium occidentale L.), native to northeastern Brazil, holds significant socioeconomic value, but its cultivation is limited by salinity, which is common in semiarid regions. This study evaluates foliar magnesium (Mg) application as a strategy to mitigate salinity stress in cashew seedlings. A greenhouse experiment was conducted with two genotypes (CCP 76 and AT01), two irrigation salinity levels (0.5 and 2.5 dS m⁻¹), and three Mg doses (0, 1, and 2 mL L⁻¹). Salinity reduced growth, physiological parameters, and stomatal conductance. Foliar Mg application, particularly at 1 mL L⁻¹, alleviated these effects by increasing root dry mass, stomatal conductance, internal CO₂ concentration, and intrinsic water-use efficiency, especially in genotype AT01. The 2 mL L⁻¹ dose showed inconsistent responses, suggesting toxicity. Overall, Mg application mitigates salinity effects in cashew, with efficiency dependent on genotype and dose, and AT01 demonstrating greater tolerance. Full article

Accurate discharge measurement in irrigation channels is critical for improving water use efficiency and optimizing water allocation. To investigate the controlling factors of sediment deposition and its influence on the stage–discharge relationship, controlled experiments were conducted in a rectangular glass flume. Sediment concentration (4–16 kg/m³), bed slope (0.0005–0.002), and discharge (15–45 L/s) were systematically varied, and longitudinal deposition thickness and corresponding water stages were measured. Results indicate that sediment concentration is the dominant factor controlling deposition thickness, exhibiting a downstream-decreasing influence, with pronounced differences upstream and convergence downstream. Bed slope and discharge mitigate deposition by enhancing near-bed hydraulics; upstream deposition thickness decreased by approximately 35% and 23% as slope increased from 0.0005 to 0.002 and discharge increased from 15 to 45 L/s, respectively, with the regulatory effect diminishing along the flow direction. Three-dimensional response analysis revealed a compound “concentration-dominated and hydraulically regulated” mechanism: under low-discharge, low-slope, and high-concentration conditions, the ratio of deposition thickness to measured water depth (h_d/h) exceeded 15%, whereas it decreased below 5% under high-discharge, high-slope, and low-concentration conditions. Sediment deposition elevated the overall water stage by approximately 3–4% and caused systematic overestimation of stage-based discharge, with errors reaching 31.4% under low-discharge and high-concentration conditions and decreasing to 4.94% under high-discharge and steep-slope conditions. These findings provide quantitative evidence for discharge measurement and stage–discharge relationship calibration in sediment-laden open channels. Full article

Climate change is expected to increasingly intensify the water stress that directly impacts crop productivity in the near future. This study integrates the crop water stress index (CWSI) with high-resolution regional climate simulations produced by the weather research and forecasting (WRF) model to evaluate water stress that winter wheat and olive trees will potentially experience in Greece in the future. Decadal, high-resolution climate simulations were generated for both the present and near-future periods using the most recent shared socioeconomic pathways (SSP) framework. A bias-corrected dataset based on 18 models from the Coupled Model Intercomparison Project 6 was used for boundary conditions to mitigate errors associated with individual global model biases. Projections indicated a mean air temperature increase of 1.1–1.7 °C and a relative humidity decrease of up to 3.5%. Mean CWSI increases of up to 6% and 4% were projected in most of the country for winter wheat and olive trees, respectively. The water stress of the winter wheat was also assessed over the three growing stages defined by the FAO. The analysis showed that water stress may occur during all growing stages, inducing potential impacts on tillering, photosynthetic efficiency, biomass accumulation, or yield. Additionally, a water stress threshold (i.e., CWSI > 0.5) was applied for both species in order to carry out a spatial assessment of the water stress that is projected to occur in the future in key winter wheat-, olive oil- and table olive-producing Greek regions. The findings of this study can support the irrigation scheduling and the development of climate-resilient agricultural practices in Greece. The modeling framework that was established in this study can also be applied to other crops and regions in the Mediterranean. Full article

This study aimed to evaluate the effect of selenium concentrations in mitigating salt stress on the physiology, growth, and yield of okra plants irrigated with brackish water. Treatments consisted of four irrigation water salinity levels (ECw: 0.4, 1.3, 2.2, and 3.1 dS m⁻¹) combined with four selenium concentrations (0, 5, 10, and 15 mg L⁻¹), arranged in a randomized block design in a 4 × 4 factorial scheme, with three replicates and one plant per plot. Increasing irrigation water salinity from 0.4 dS m⁻¹ reduced relative water content, gas exchange, initial chlorophyll a fluorescence, plant growth, and production of okra, while increasing the percentage of electrolyte leakage. Irrigation Water salinity levels above 0.4 dS m⁻¹ impaired plant water status, gas exchange, growth, chlorophyll a fluorescence, yield, and water-use efficiency, while increasing electrolyte leakage. Salinity above 1.0 dS m⁻¹ also inhibited photosynthetic pigment synthesis. Selenium did not mitigate salinity-induced reductions in chlorophyll and carotenoids. However, foliar Se at 8.6–15 mg L⁻¹ enhanced gas exchange, chlorophyll a fluorescence, growth, and fruit yield under salinity up to 3.1 dS m⁻¹. These results support Se induced attenuation of salinity stress, warranting further mechanistic studies. Full article

Nitrogen (N) and water are key resources for crop production and improving the efficiency with which they are used remains a major global challenge in intensive cropping systems. Here, we report how crop yield, N and water use efficiency, N surplus, and economic benefits can be improved from optimized management and crop rotations. A conventional winter wheat–summer maize double cropping (CN/WM) rotation in a three-year field experiment in the North China Plain is compared with alternative optimized rotations. The first three optimized treatments were wheat–summer maize rotation with optimized N and irrigation rates, tillage and straw management (ON/WM), and partial manure substitution (ONM/WM) or biochar addition (ONB/WM); the fourth optimized treatment was winter wheat–summer maize–spring maize producing three harvests in two years (ON/WMM); and the last was spring maize incorporating green manure during the fallow season for one harvest per year (ON/GM). The results showed that the ON/WM, ONM/WM, and ONB/WM had comparable yields to CN/WM, but significantly increased N use efficiency by 19–41% and water use efficiency by 13–20% and reduced N surplus to 353–531 kg N ha⁻¹ 2yr⁻¹. From these three optimized treatments, the ONM/WM performed better, with a comprehensive evaluation index of 0.66 and the highest economic benefits. The ON/WMM and ON/GM treatments also significantly increased N and water use efficiency but resulted in relatively low crop yields and profits; nevertheless, they significantly reduced water use and are suitable for water saving cropping systems. We concluded that optimized management-combined manure with synthetic N fertilization in wheat–summer maize rotations can achieve high crop productivity, environmental, and economic benefits, which contribute to a more sustainable crop production. Full article

Water and nitrogen are the key factors restricting the productivity improvement of onion in the Hexi Oasis. Unreasonable water and fertilizer management not only increases input costs, but also causes environmental pollution of farmland soil, thereby affecting the sustainable development of agriculture. To explore the effects of the water–nitrogen interaction and optimized combination schemes on onion yield, water–nitrogen use efficiency, and economic benefits under mulched drip irrigation in the Hexi Oasis, a four-year (2020–2023) water–nitrogen coupling regulation experiment was conducted at the Yimin Irrigation Experimental Station in Minle County, Hexi Corridor. The onion was used as the test crop and three irrigation levels were established, based on reference crop evapotranspiration (ET_c): low water (W1, 70% ET_c), medium water (W2, 85% ET_c), and sufficient water (W3, 100% ET_c), as well as high nitrogen N3 (330 kg·ha⁻¹), medium nitrogen N2 (264 kg·ha⁻¹), and low nitrogen N1 (198 kg·ha⁻¹). Meanwhile, no nitrogen application N0 (0 kg·ha⁻¹) was set as the control at three irrigation levels. This study analyzed the effects of different water and nitrogen supply conditions on onion quality, yield, water–nitrogen use efficiency, and economic benefits. A water–nitrogen economic benefit coupling model was established to optimize water–nitrogen combination schemes targeting different economic objectives. The results revealed that medium-to-high water–nitrogen combinations were beneficial for improving onion quality, while excessive irrigation and nitrogen application inhibited bulb quality accumulation. Both yield and economic benefits increased with the increasing amount of irrigation, whereas excessive nitrogen application showed a diminishing yield-increasing effect, simultaneously increasing farm input costs and ultimately reducing the economic benefits. In the four-year experiment, the N3W3 treatment in 2020 achieved the highest yield, economic benefits, and net profit, reaching 136.93 t·ha⁻¹, 20,376.3 USD·ha⁻¹, and 14,320.8 USD·ha⁻¹, respectively, with no significant difference from the N2W3 treatment. From 2021 to 2023, the N2W3 treatment achieved the highest yield, economic benefits, and net profit, averaging 130.87 t·ha⁻¹, 28,449.5 USD·ha⁻¹, and 21,881.5 USD·ha⁻¹, respectively. Lower irrigation and nitrogen application rates mutually restricted the water and nitrogen utilization, resulting in low water use efficiency, irrigation water use efficiency, nitrogen partial factor productivity, and nitrogen agronomic use efficiency. The relationship between the irrigation amount, nitrogen application rate, and the economic benefits of onion fits a bivariate quadratic regression model. This model predicts that onion’s economic benefits are highly correlated with the actual economic benefits, with analysis revealing a parabolic trend in economic benefits as water and nitrogen inputs increase. By optimizing the model, it was determined that when the irrigation amount reached 100%, the ET_c and nitrogen application rate was 264 kg·ha⁻¹, and the economic benefits were close to the target range of 27,000–29,000 USD·ha⁻¹; this can be used as the optimal water and nitrogen management model and technical reference for onion in the Hexi Oasis irrigation area, which can not only ensure high yield and quality but also improve the use efficiency of water and nitrogen. Full article