Search Results (302)

Cyanobacterial blooms are an increasing global concern due to the release of microcystins (MCs), potent hepatotoxins that threaten aquatic ecosystems, livestock, and human health. This study investigated the efficiency of low-cost natural adsorbents—rice straw (R), corn straw (C), and sawdust (S)—compared with commercial activated charcoal (AC) for the removal of microcystins from water sources in Upper Egypt. A total of 72 water samples were collected between June and September 2022 from rivers, irrigation canals, and wastewater channels in Sohag and Assiut governorates. Samples were analyzed for intra- and extracellular MCs using ultra-performance liquid chromatography (UPLC), while adsorbents were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM), pH, moisture content, iodine number, and methylene blue adsorption. Results revealed mean total MC concentrations of 9.39, 3.18, and 11.70 µg/L in river, irrigation, and wastewater samples, respectively—exceeding the World Health Organization (WHO) guideline of 1 µg/L. Adsorption experiments demonstrated that AC exhibited the highest MC removal efficiencies (88.9% in acidified and 92.3% in neutral water), followed by sawdust (84–86.2%), corn straw (74.01–85.2%), and rice straw (75.4–74.8%). Sawdust and corn straw performed particularly well for extracellular MC removal, while AC was most effective for intracellular fractions. This study highlights the potential of agricultural by-products, particularly sawdust and corn straw, as sustainable, low-cost alternatives to activated charcoal for cyanotoxin removal. Their availability and efficiency support their application in water treatment systems without chemical pretreatment. These findings indicate that agricultural residues could serve as practical, low-cost adsorbents for mitigating cyanotoxin contamination in water, especially in resource-limited regions, while also promoting the beneficial reuse of agricultural waste. Full article

This study presents the results of long-term field experiments investigating the effects of subsurface heating and irrigation with discharged warm water (28–35 °C) on the hydrothermal, redox, biological, and salt regimes of Haplic Chernozem (Loamic, Endocalcaric) in the central Forest-Steppe zone of Ukraine. The experiments were conducted under contrasting hydro-meteorological conditions, allowing assessment of thermo-reclamation practices across a wide range of temperature and soil moisture regimes. Subsurface heating increased soil temperature by 7.3–11.1 °C at the depth of heating pipe installation, while the thermal effect gradually decreased with increasing distance from the heat source. Combined heating and irrigation created a more uniform temperature distribution within the root zone, reduced the depth and duration of soil freezing, and improved hydrothermal conditions throughout the growing season. The studied soils maintained predominantly oxidative conditions under all treatments. However, the combined application of heating and irrigation promoted a more homogeneous distribution and seasonal stabilization of soil redox potential throughout the profile. Soil heating also enhanced microbiological activity, thereby increasing cellulolytic activity, particularly during cold and dry periods when soil temperature and moisture limited microbial processes. Irrigation with slightly mineralized warm wastewater did not cause significant overall soil salinization but resulted in the redistribution of calcium and sodium within the soil profile. Subsurface heating intensified the seasonal dynamics of readily soluble salts, promoting their temporary accumulation near the heating pipes, whereas combined heating and irrigation facilitated subsequent leaching of excess salts into deeper horizons. The integrated application of subsurface heating and irrigation produced the highest and most stable perennial grass productivity, increasing biomass yield by 87–163% compared with the control, irrespective of meteorological conditions. These findings demonstrate that the integrated use of industrial waste heat for subsurface heating combined with irrigation represents a promising and environmentally sustainable thermo-reclamation technology capable of improving soil functioning and agricultural productivity, provided that long-term monitoring of soil water–salt regimes is maintained. Full article

Traditional soil management relies on “whole-field” averages, which leads to resource waste and environmental degradation under anthropogenic pressures. While combining electromagnetic induction (EMI) and remote sensing is known for digital soil mapping, current approaches lack a unified, automated framework to handle complex multi-source data dependencies for local-scale precision irrigation. To overcome this limitation, this study introduces a novel integrated methodology that couples high-resolution geophysical datasets and remote/proximal sensing through an automated machine learning workflow, capturing dynamic soil–human interaction boundaries more precisely than traditional empirical overlays. The general methodology was tested in a vineyard plot within the Torre Guaceto Natural Reserve (Southern Italy). Spatial datasets from EMI and remote sensing were integrated. Crucially, the K-means clustering algorithm was deployed early in the workflow to optimize the fused datasets and classify the plot into homogeneous zone clusters. The machine learning approach successfully identified two distinct main soil clusters. The spatial boundaries of these zones were rigorously validated using in situ soil moisture data from capacitance sensors, showing a statistically significant variance in volumetric water content between the two zones. This study demonstrates that integrated machine learning workflows can accurately delineate precision agricultural zones without relying on high-cost exhaustive sampling. It is recommended that farmers and managers within sensitive nature reserves adopt this cluster-based Variable Rate Application (VRA) for water and fertilizers to optimize resource efficiency and prevent nutrient leaching into underlying aquifers. Full article

In the future, agriculture will need better irrigation management options to produce more food and decrease its air and water pollution contributions. Hydroponic systems conserve water over field production, but up to 50% of applied irrigation could be discharged from open-drain systems. TVPD is an evapotranspiration model developed for greenhouse production, particularly for hydroponics. In this study, we calibrate and evaluate TVPD on environmental and evapotranspiration data from hydroponic tomato production and compare predictions to those of random forest (RF) and K-nearest neighbors (KNN). Using five time-ordered data splits, we sought to gauge prediction accuracy for data-limited settings, where the model needs to be implemented with the least calibration time possible, and we evaluated TVPD, RF, and KNN with a 10-fold cross-validation to assess overall model robustness. Across the five data splits, TVPD produced more accurate predictions (r²: 0.86 to 0.90; RMSE: 0.1739 to 0.5796 L tray⁻¹) than RF (r²: 0.06 to 0.73; RMSE: 0.7354 to 2.0505 L tray⁻¹) and KNN (r²: 0.06 to 0.59; RMSE: 0.7694 to 1.7090 L tray⁻¹). With calibration on only the first five days of data, TVPD was able to produce acceptable predictions (r² = 0.87, RMSE = 0.5796 L tray⁻¹). The mean r² for a 10-fold cross-validation was 0.81 for TVPD, 0.88 for RF and 0.81 for KNN, and mean RMSE values were slightly better for the cross-validation for RF (0.4970 L tray⁻¹) and KNN (0.4968 L tray⁻¹) than for TVPD (0.5922 L tray⁻¹). Overall, TVPD could be a useful model to predict evapotranspiration for irrigation management and could decrease the volume of discharged hydroponic waste solution. Full article

In the Kingdom of Saudi Arabia (KSA) and other arid regions, higher education institutions account for a significant share of energy consumption and greenhouse gas (GHG) emissions. Improving the environmental performance of higher education institutions is important to achieving nationwide impact reduction. This study evaluates the water, energy, and carbon (WEC) footprint of higher education campuses in arid environments. Qassim University (QU), KSA, is a leading public institution of higher education and research in Buraydah City and was selected for this study. A comprehensive assessment based on the GHG Protocol was conducted for the period 2022–2025, covering Scope I, II, and III emissions. This study analyzed institutional data on water use, wastewater, electricity consumption, transportation, waste generation, and air travel. The results show that total water consumption increased from 354,747 m³ in 2022 to 547,268 m³ in 2025, with per capita use rising from 46.2 to 61.7 L/c/day. Net water demand, including irrigation, reached 877,456 m³ in 2025. The declining trend in energy consumption between 2022 and 2025 reflects significant (33%) energy savings with the use of sensors and the overall tendency towards sustainability. Correspondingly, Scope II emissions decreased significantly from 147.2 million kg CO₂/year to 99.1 million kg CO₂/year and were the dominant CO₂ contributor (60–75% of total emissions). In contrast, Scope III emissions from commuting staff and students increased, with transport-related emissions rising from 36.4 million kg CO₂/year in 2022 to 52.2 million kg CO₂/year in 2025. This study also evaluated current and potential CO₂ emission reduction scenarios targeting energy and transportation systems on the QU campus. The findings indicate that the deployment of a 5.1 MW solar energy system can generate approximately 8.6 million kWh annually, resulting in a reduction of around 4000 tCO₂ and contributing to nearly 43% of the 2030 emission reduction target. In addition, transportation-focused strategies—including modal shift, vehicle electrification, and hybrid learning approaches—demonstrate significant mitigation potential, with total reductions reaching up to 18,700 tCO₂ by 2030. Overall, this study contributes to the limited body of knowledge on WEC footprint assessments on university campuses in arid regions and provides a baseline for future sustainability planning. Full article

Improving water–fertilizer use efficiency and maintaining the long-term operational stability of irrigation systems are critical challenges for sustainable agricultural development, particularly in arid and semi-arid regions. However, emitter clogging in drip irrigation systems significantly reduces irrigation uniformity, increases resource waste, and threatens the sustainability of fertigation practices. This study systematically investigated the coupled effects of fertilizer concentration and sediment content on emitter clogging in drip tape systems through a two-factor, three-level full-factorial experiment using emitters with flow rates of 2.0 and 3.0 L h⁻¹, under sediment contents of 1.0, 2.0, and 3.0 g L⁻¹ and fertilizer concentrations of 0.2, 0.5, and 0.8 g L⁻¹. The effects of these factors on the relative average flow rate (Dra), coefficient of variation (Cv), and dry weight of clogging material were analyzed. The results showed that emitter performance gradually deteriorated with operating time. At the end of the experiment (144 h), the relative average flow rate (Dra) decreased by 15.75–54.66%, the coefficient of variation (Cv) increased to 0.12–0.55, and the dry weight of clogging material reached 16.85–43.92 mg. Analysis of variance showed that sediment content was the dominant factor, fertilizer concentration acted as an aggravating factor, and their interaction was significant. The clogging material consisted primarily of silicate and carbonate minerals. Quartz and clay minerals were mainly controlled by sediment content, whereas calcite was mainly associated with fertilizer concentration; these components accumulated over time to form composite clogging deposits. Path analysis indicates that sediment directly drives the clogging process by enhancing particle deposition, while fertilizer indirectly exacerbates clogging development by promoting the accumulation of precipitates; the two factors act synergistically to exacerbate clogging development. Prediction results using the random forest model showed high accuracy (R²: 0.843–0.951). In summary, the clogging of drip irrigation emitters is driven by both sediment particle deposition and chemical precipitation of fertilizers, with sediment determining the extent of clogging and fertilizers influencing the accumulation characteristics of clogging material. In agricultural practice, controlling sediment input and optimizing fertilizer concentration can reduce emitter clogging risk, improve system stability, and support sustainable drip irrigation by enhancing irrigation uniformity and water–fertilizer use efficiency. Full article

Valorization of agricultural residues into biochar for soil applications offers dual benefits of waste management and sustainable agriculture. However, the mechanisms governing sandy soil and lettuce response to biochar under deficit irrigation are not well understood. This study evaluated the effects of biochar types on sandy soil physiochemical properties and lettuce (Lactuca sativa L.) yield at different irrigation levels. A field experiment was performed using a randomized complete block design with four treatments (soil only, cotton stalk biochar, cashew nutshells biochar, and a mix of cotton stalks+ cashew nutshells biochar) and three irrigation regimes (100%, 80, and 60% of crop water requirements ETc) in Ouagadougou, Burkina Faso. The results showed that biochar-amended soils had consistently higher water retention and macronutrients, resulting in higher fresh, marketable lettuce yields under deficit irrigation compared to untreated soils. Compared to other treatments, a mix of cotton-stalk and cashew-nutshell biochar produced the highest yield (18.1 tons/ha) under moderate irrigation (80% ETc). Achieving optimal yields with 20% less irrigation water indicates biochar’s water-saving potential in climate-resilient vegetable farming. These findings underscore the potential of combining deficit irrigation and biochar for sustainable vegetable production to mitigate food security in water-scarce regions. Full article

The chemical equilibria of metal ions between soil solution and solid phases govern the solubility of metals in soil. However, the identity of these controlling phases remains poorly understood in historically polluted environments. This study aimed to identify the dominant mineral phases regulating the activities of Zn²⁺, Cd²⁺, Pb²⁺, and Ni²⁺ in soils subjected to long-term contamination from sewage sludge, municipal solid waste, river water, and industrial effluents across India. The soil samples were collected from various locations historically polluted by sewage sludge, municipal solid waste, polluted river water and industrial effluents. The free ion activities of Zn²⁺ (pZn²⁺), Cd²⁺ (pCd²⁺), Pb²⁺ (pPb²⁺) and Ni²⁺ (pNi²⁺) in soil pore water were estimated using the geochemical speciation model WHAM-VII. The metal ion activities were higher in industrial effluents and solid waste-treated soils as compared to other contaminated soils. The solubility of Zn and Cd in soils contaminated with Zn-smelter effluents was controlled by franklinite (ZnFe₂O₄) in equilibrium with goethite (α-FeOOH) and otavite (CdCO₃), respectively. Identification of minerals further reveals that nickel ferrite (NiFe₂O₄) in equilibrium with lepidocrocite (γ-FeOOH) governs the activity of Ni²⁺ in cycle factory effluent-irrigated soils of Sonepat, Haryana. At the municipal solid waste-contaminated site, the Pb²⁺ activity was controlled by exchangeable Pb in soils, whereas Zn²⁺ activity was governed by willemite (Zn₂SiO₄) in equilibrium with quartz (SiO₂). These findings provide new insights into mineralogical controls on heavy metal solubility under diverse contamination scenarios. Formation of highly soluble minerals like otavite, willemite, and nickel ferrite suggested the potential ecological risk of Cd, Zn, and Ni, respectively, in polluted soils. Full article

Sustainable vegetable production requires strategies that optimize yield while conserving water and minimizing resource inputs. This study, conducted at the Horticulture Research Farm near Absaraka, ND, evaluated the performance of several paste-type tomato (Solanum lycopersicum) cultivars under different irrigation strategies in high-tunnel and open-field production systems to identify cultivar and irrigation combinations that support sustainable production. Across seasons and production environments, cultivar significantly influenced marketable yield, fruit number, fruit size, and the proportion of unmarketable fruit, whereas irrigation treatments had limited effects on total and marketable yield. High-yielding cultivars such as ‘Granadero’, ‘Pozzano’, ‘Cauralina’, and ‘Amish Paste’ consistently produced greater marketable yields in both production systems, although ‘Cauralina’ also exhibited higher levels of fruit cracking and unmarketable yield. In high-tunnel production, deficit irrigation strategies based on soil moisture thresholds (10% and 30% management allowable depletion) maintained yields comparable to time-based irrigation, suggesting that water-efficient irrigation scheduling can sustain productivity. In the open field, cultivar responses varied under different irrigation regimes, highlighting the importance of selecting cultivars adapted to water-limited conditions. Fruit quality attributes, including soluble solids content and titratable acidity, were primarily influenced by cultivar rather than irrigation. Overall, the findings demonstrate that cultivar selection combined with water-efficient irrigation management can maintain tomato productivity while reducing water use and production losses. These results support the development of more sustainable tomato production systems that enhance resource-use efficiency, reduce waste from unmarketable fruit, and maintain fruit quality across diverse production environments. Full article

Modern agriculture has to alleviate extremes in water demand and/or water waste. In this regard, this work showcases how soil moisture instruments can be combined with low-end microcontrollers, energy-efficient communication protocols, single-board computers, flow and pressure sensors, and purpose-built actuators to form a synergistic platform able to generate and study realistic irrigation scenarios. These scenarios, potentially emulating anomalies such as clogged emitters or pipe leaks with a satisfactory time granularity of a few minutes, provide valuable data that pave the way for the creation of intelligent models intercepting water misuse events and/or irrigation failures. The proposed system utilizes widely available, well-documented, low-cost components to form a functioning whole which is optimized for outdoor, low-power, low-maintenance and long-term operation and is accessible remotely via typical end-user devices. Two drip irrigation points were set up, each having a TEROS 12 and a TEROS 10 instrument placed at different depths, while a prototype water flow/pressure control and report system was developed. All modules sent data in real time, via LoRa, to a central node implemented using a Raspberry Pi for further processing and to make them widely available via common network infrastructures, also provisioning for remote scenario invocation. The system does not claim to achieve specific irrigation water savings, but it contributes to maintaining/increasing the benefits of modern irrigation practices (such as drip irrigation). This goal is served by emulating a wide variety of irrigation events and by gathering and studying the corresponding data. These multimodal data are collected at a frequency of a few minutes, reflecting key irrigation-specific parameters with an accuracy better than or equal to 3%. The exact steps for specific hardware and software component interoperation are clearly explained, allowing other teams of researchers and/or university educators worldwide to be inspired and benefit from platform replication. Full article

Weed management is crucial for the sustainable production of rice (Oryza sativa L.), although herbicides such as Imazamox (IZX) can persist in soils, posing risks to soils and water resources. This two-year study evaluated the effects of soil physicochemical properties under different irrigation and tillage practices, with and without compost derived from olive mill waste, on IZX behavior. The treatments implemented were as follows: no-tillage and sprinkler (NT-S), conventional tillage and sprinkler (T-S), conventional tillage and flooding (T-F), and the corresponding regimes with compost amendment (NT-SC, T-SC, and T-FC). Sorption–desorption, dissipation, and leaching of the herbicide were assessed. The IZX adsorption was lower under soil collected from sprinkler irrigation, especially in NT-S, while compost reduced the adsorption under T-SC and T-FC. Dissipation was faster in NT-S and T-S soils, in which the half-life of IZX declined up to 30% relative to T-F. Furthermore, compost further accelerated herbicide dissipation, correlating with higher organic carbon content and microbial activity. The IZX losses via leaching were significantly reduced in soils irrigated by sprinkler in combination with compost, with values ≤ 48.5% of the IZX applied. These results indicate that the irrigation regime and organic amendment strongly influence soil physicochemical properties, then influencing the environmental fate of IZX. Integrated management using sprinkler irrigation and compost can mitigate IZX persistence and leaching, improve soil health, and reduce the risk of water contamination, representing a sustainable strategy for rice cultivation. Full article

This paper presents a mathematical programming model to optimize the design and sustainability performance of the urban food–energy–water (FEW) nexus. The model incorporates a micro supply chain and addresses the supply-demand balance within existing and future FEW systems using performance indicators such as cost and carbon footprint. The problem allows for optimal discrete choices, such as investment in new assets, as well as continuous choices, including capacity of different units and produce exchange among urban farms. The model is applied to an urban agriculture network in South Florida that integrates renewable energy technologies (solar, wind, biomass), combined heat and power (CHP) units, reclaimed wastewater and stormwater for irrigation, and electric vehicles for produce transport. The optimization process identifies the most effective infrastructure investment decisions, resource allocation, and technology configurations to support circular economy practices and long-term sustainability objectives. The proposed framework enables reductions in carbon footprints, food waste, and improves food accessibility in food deserts and strengthens collaboration among urban farms. It supports the planning of resilient urban FEW systems by aligning resource use with social, economic and environmental sustainability objectives. The results provide a decision-support tool for urban planners and policymakers, offering practical insights to guide infrastructure investment and sustainability planning in other geographic regions. Full article

Water scarcity, rapid soil moisture loss, and high evaporative demand severely limit vegetable production in arid regions such as Qatar. Sustainable soil amendments that enhance water retention and stabilize plant water status are therefore critical for improving productivity. This study evaluated a biodegradable hydrogel synthesized from date-palm leaf cellulose using a sodium alginate crosslinking method and assessed its effects on soil hydro-physical properties and tomato (Solanum lycopersicum L.) performance under arid conditions. A pot experiment was conducted under semi-controlled conditions using a single-factor randomized complete design with three hydrogel rates (0, 1, and 2% w/w) and three replications, with one plant per pot. All treatments received the same seasonal irrigation depth, scheduled when soil moisture declined to approximately 60–65% of field capacity. The hydrogel exhibited rapid hydration behavior, reaching equilibrium within 30–60 min with a swelling ratio of 5.659 g g⁻¹, corresponding to a water uptake of 465.9%, and SEM analysis revealed a porous internal structure favorable for water retention. At 1 and 2% application rates, hydrogel significantly reduced bulk density, increased total porosity and field capacity, and maintained higher soil moisture across irrigation cycles. Tomato plants grown in hydrogel-amended pots showed substantial gains in fresh biomass and root length, together with higher chlorophyll content, leaf nitrogen concentration, and relative water content. Water use efficiency improved significantly at 1% hydrogel, whereas the 2% rate showed a positive but non-significant trend. Overall, the results demonstrate that hydrogels derived from date-palm waste can enhance soil water retention, plant physiological status, and tomato productivity, offering a locally relevant strategy to improve agricultural resilience in arid environments. Full article

Water scarcity in arid/semi-arid regions restricts agricultural sustainability systems and hinders the achievement of regional sustainable development goals, especially in northwest China’s extremely arid areas, where acute water supply–demand conflicts and inefficient traditional practices intensify competition for water between agricultural and ecological sectors. This study aims to verify the effectiveness of an intelligent automatic irrigation system in mitigating water scarcity pressures and enhancing agricultural sustainability in the Shule River Basin of northwestern China, a region where traditional irrigation methods not only yield suboptimal crop outputs but also undermine long-term water resource sustainability. A smart irrigation module, integrating “sensing–decision–execution” processes, was embedded within a digital twin platform to enable precise, resource-efficient water management that aligns with sustainable development principles. Sunflower (Helianthus annuus L.), the most popular cash crop in the area, was used as the test crop, with three soil moisture-based irrigation levels compared against traditional farmer practices. Key indicators including leaf area index (LAI), dry biomass, grain yield, and irrigation water use efficiency (IWUE) were systematically evaluated. The results showed that (1) LAI increased from the seedling to flowering stage, with smart irrigation treatments significantly outperforming farmer practices in both crop growth and water-saving effects, laying a foundation for sustainable yield improvement; (2) total dry biomass at maturity was positively correlated with irrigation amount but smart irrigation optimized the allocation of water resources to avoid waste, balancing productivity and sustainability; (3) grain yield peaked within 70–89% field capacity (fc), with further increases leading to diminishing returns and unnecessary water consumption that impairs sustainable water use; (4) IWUE followed a parabolic trend, reaching its maximum under the same optimal irrigation range, indicating that smart irrigation can maximize water productivity while preserving water resources for ecological and future agricultural needs. The digital twin-driven smart irrigation system enhances both crop yield and water productivity in arid regions, providing a scalable model for precision water management in water-stressed agricultural zones. The results provide a key empirical basis and technical approach for sustainably using irrigation water, optimizing water–energy–food–ecology synergy, and advancing sustainable agriculture in arid regions of Northwest China, which is crucial for achieving regional sustainable development objectives amid worsening water scarcity. Full article

The citrus processing industry generates large amounts of organic residues whose sustainable management is a major environmental challenge. The aim of this study was to evaluate the effects of incorporating citrus-derived waste (CW) into coconut-coir-based substrates on tomato (Solanum lycopersicum L., cv. Proxy) under different irrigation regimes (I) in a factorial design (CW × I) with three replications. Each replicate consisted of six plants (pots), and the replicate was considered the experimental unit. Plants were grown in substrates amended with 0%, 6.25%, 12.5%, 25.0%, and 37.5% (v/v) citrus waste and subjected to three water regimes (100%, 75%, and 50% of the standard water supply). Plant growth, biomass allocation, yield components, and fruit quality traits were assessed. Results indicate that CW can be incorporated into coconut-coir substrates without detectable penalties in total production at low-to-moderate rates (6.25–12.5%) across all irrigation regimes. Yield reductions of 18% (from 3398 to 2789 g plant⁻¹) attributable to CW were observed mostly at the highest inclusion rates under moderate deficit irrigation (75% water supply), whereas under severe deficit (50% water supply), production declined across all CW rates, including 0%, indicating that water deficit has a dominant limiting effect. Fruit quality parameters were generally maintained or improved in amended substrates, particularly under reduced irrigation with deficit irrigation, generally increasing total soluble solids at 100%, 75%, and 50% WC (+13%, +19%, and +9%, respectively). Overall, these findings support the use of citrus waste at low-to-moderate proportions as a sustainable amendment for soilless tomato cultivation without marked negative effects on yield and fruit quality, enabling its use as a locally sourced substrate component within circular-economy strategies. Full article