Search Results (131)

Desalination is becoming crucial to meet the increasing global demand for potable water. Despite its benefits, desalination produces reject brine, a highly concentrated saline byproduct, which poses substantial environmental risks if not managed properly. It contains high levels of salts and other potentially harmful compounds, which, when discharged into oceans or land, can disrupt habitats, degrade soil quality, and harm biodiversity, creating serious environmental challenges. In response to these challenges, this study investigated various uses for reject brine, aiming to reduce its environmental footprint and explore its potential applications. This review paper synthesizes findings from previous studies on the disposal, management, and applications of reject brine in fields such as concrete production, road construction, and ground stabilization. In addition, this review highlights the potential cost savings and resource efficiency resulting from the utilization of reject brine, as well as the mitigation of environmental impacts associated with traditional disposal methods. This paper also provides a comprehensive overview of existing technologies and approaches used to utilize reject brine in various industries, including construction. This review contributes to the growing body of knowledge on environmentally friendly solutions for reject brine, emphasizing its potential role in supporting sustainable development goals through resource reutilization and waste minimization. The study also highlights current research gaps that are still unaddressed, hindering the complete realization of the full potential of reject brine as a sustainable resource. Full article

The coastal tidal flat area of Jiangsu Province, China, is vast and has great potential for carbon sequestration. Planting oat in saline–alkaline land can increase carbon sequestration from the atmosphere into soil and, thus, improve soil quality. Harvesting oats can act as a biological desalination mechanism, and long-term planting may transform saline–alkaline land into high-quality arable land. Our experiment selected two oat varieties, Caesar (V1) and Menglong (V2), and used urea, organic fertilizer, microbial inoculant, and biochar as experimental factors to investigate the effects of fertilizers and soil amendments on soil improvement and carbon sequestration when cultivating oats. The results showed that when planting V1, the carbon sequestration of the farmland ecosystem was the highest with microbial inoculant and organic fertilizer treatments, and the soil salinity decreased the most with biochar treatment. When planting V2, the carbon sequestration of the farmland ecosystem was the highest with the urea + biochar treatment, the soil salinity decreased the most with organic fertilizer + microbial inoculant treatment, and the soil organic carbon content increased the most with organic fertilizer + biochar treatment. We found that the application of organic fertilizer and biochar significantly increased soil organic carbon (SOC) content by 22.03% compared to the control treatment. Additionally, the combined treatment of urea and biochar resulted in the highest agricultural carbon sink, with a 74.62% increase in oat carbon storage compared to conventional fertilization. Full article

Soil salinization presents a significant challenge, driven by factors such as inadequate drainage, shallow aquifers, and high evaporation rates, threatening global food security. The sunflower emerges as a key cash crop in such areas, providing the opportunity to convert its straw into biochar, which offers additional agronomic and environmental benefits. This study investigates the effectiveness of biochar interlayers in enhancing salt leaching and suppressing upward salt migration through integrated laboratory and field experiments. The effectiveness of varying biochar interlayer application rates was assessed in promoting salt leaching, decreasing soil electrical conductivity (EC), and enhancing crop performance in saline soils through a systematic approach that combines laboratory and field experiments. The biochar treatments included a control (CK) and different applications of 20 (BL20), 40 (BL40), 60 (BL60), and 80 (BL80) tons of biochar per hectare, all applied below a depth of 20 cm, with each treatment replicated three times. The laboratory and field experimental setups maintained consistency in terms of biochar treatments and interlayer placement methodology. During the laboratory column experiments, the soil columns were treated with deionized water, and their leachates were analyzed for EC and major ionic components. The results showed that columns with biochar interlayers exhibited significantly higher efflux rates compared to those of the control and notably accelerated the time required for the effluent EC to decrease to 2 dS m⁻¹. The CK required 43 days for full discharge and 38 days for EC stabilization below 2 dS m⁻¹. In contrast, biochar treatments notably reduced these times, with BL80 achieving discharge in just 7 days and EC stabilization in 10 days. Elution events occurred 20–36 days earlier in the biochar-treated columns, confirming biochar’s effectiveness in enhancing leaching efficiency in saline soils. The field experiment results supported the laboratory findings, indicating that increased biochar application rates significantly reduced soil EC and ion concentrations at depths of 0–20 cm and 20–40 cm, lowering the EC from 7.12 to 2.25 dS m⁻¹ and from 6.30 to 2.41 dS m⁻¹ in their respective layers. The application of biochar interlayers resulted in significant reductions in Na⁺, K⁺, Ca²⁺, Mg²⁺, Cl⁻, SO₄²⁻, and HCO₃⁻ concentrations across both soil layers. In the 0–20 cm layer, Na⁺ decreased from 3.44 to 2.75 mg·g⁻¹, K⁺ from 0.24 to 0.11 mg·g⁻¹, Ca²⁺ from 0.35 to 0.20 mg·g⁻¹, Mg²⁺ from 0.31 to 0.24 mg·g⁻¹, Cl⁻ from 1.22 to 0.88 mg·g⁻¹, SO₄²⁻ from 1.91 to 1.30 mg·g⁻¹ and HCO₃⁻ from 0.39 to 0.18 mg·g⁻¹, respectively. Similarly, in the 20–40 cm layer, Na⁺ declined from 3.62 to 3.05 mg·g⁻¹, K⁺ from 0.28 to 0.12 mg·g⁻¹, Ca²⁺ from 0.39 to 0.26 mg·g⁻¹, Mg²⁺ from 0.36 to 0.27 mg·g⁻¹, Cl⁻ from 1.18 to 0.80 mg·g⁻¹, SO₄²⁻ from 1.95 to 1.33 mg·g⁻¹ and HCO₃⁻ from 0.42 to 0.21 mg·g⁻¹ under increasing biochar rates. Moreover, the use of biochar interlayers significantly improved the physiological traits of sunflowers, including their photosynthesis rates, stomatal conductance, and transpiration efficiency, thereby boosting biomass and achene yield. These results highlight the potential of biochar interlayers as a sustainable strategy for soil desalination, water conservation, and enhanced crop productivity. This approach is especially promising for managing salt-affected soils in regions like California, where soil salinization represents a considerable threat to agricultural sustainability. Full article

An experimental evaluation of water productivity and footprint was carried out in a Mediterranean greenhouse tomato crop irrigated with different blends of desalinated seawater (DSW) for two different growing media: soil and soilless culture. Total and commercial water productivity values (expressed in terms of kg of fruit/m³ of water) and water footprint were calculated from empirical data on water consumption and crop yields. Regarding the growing media, the results of the experiment showed that the soilless culture had significantly lower water productivity and a higher water footprint, mainly due to the greater water consumption in these systems. These findings seem to indicate that fostering closed-loop soilless systems with water and nutrient recirculation is highly beneficial for improving the efficiency and sustainability of these soilless systems. The salinity of the irrigation water blends did not seem to have a significant influence on water productivity and water footprint. Nevertheless, treatments with higher DSW fractions and better quality showed slightly better productivity values and lower water footprints than those with higher salinity. These findings seem to support the fact that the conjunctive use of DSW and conventional water, within the range proposed in this study, is a favorable option from both economic and environmental perspectives. Full article

This study addresses secondary soil salinization driven by shallow groundwater in the Yanqi Basin of southern Xinjiang, focusing on subsurface drainage system (SDS) optimization for salt regulation and oil sunflower productivity improvement in severe saline–alkali soils. Through controlled field experiments conducted (May–October 2024), we evaluated five SDS configurations: control (CK, no drainage) and four drain spacing/depth combinations (20/40 m × 1.2/1.5 m). Comprehensive monitoring revealed distinct spatiotemporal patterns, with surface salt accumulation (0–20 cm: 18.59–32.94 g·kg⁻¹) consistently exceeding subsurface levels (>20–200 cm: 6.79–17.69 g·kg⁻¹). The A3 configuration (20 m spacing, 1.5 m depth) demonstrated optimal root zone desalination (0–60 cm: 14.118 g·kg⁻¹), achieving 39.02% salinity reduction compared to CK (p < 0.01). Multivariate analysis revealed strong depth-dependent inverse correlations between groundwater level and soil salinity (R² = 0.529–0.919), with burial depth exhibiting 1.7-fold greater regulatory influence than spacing parameters (p < 0.01). Crop performance followed salinity gradients (A3 > A1 > A4 > A2 > CK), showing significant yield improvements across all SDS treatments versus CK (p < 0.05). Multi-criteria optimization integrating TOPSIS modeling and genetic algorithms identified A3 as the Pareto-optimal solution. The optimized configuration (20 m spacing, 1.5 m depth) effectively stabilized aquifer dynamics, reduced topsoil salinization (0–60 cm), and enhanced crop adaptability in silt loam soils. This research establishes an engineering framework for sustainable saline–alkali soil remediation in arid basin agroecosystems, providing critical insights for water–soil management in similar ecoregions. Full article

Incessant urbanization and industrialization have resulted in several pollutants being increasingly produced and continuously discharged into the environment, altering its equilibrium, with a high risk for living organisms’ health. To restore it, new advanced materials for remediating gas streams, polluted soil, water, wastewater, groundwater and industrial waste are continually explored. Carbon-based nanomaterials (CNMs), including quantum dots, nanotubes, fullerenes and graphene, have displayed outstanding effectiveness in the decontamination of the environment by several processes. Carbon nanotubes (CNTs), due to their nonpareil characteristics and architecture, when included in absorbents, filter membranes, gas sensors, etc., have significantly improved the efficiency of these technologies in detecting and/or removing inorganic, organic and gaseous xenobiotics and pathogens from air, soil and aqueous matrices. Moreover, CNT-based membranes have displayed significant potential for efficient, fast and low-energy water desalination. However, despite CNTs serving as very potent instruments for environmental detoxification, their extensive utilization could, paradoxically, be highly noxious to the environment and, therefore, humans, due to their toxicity. The functionalization of CNTs (F-CNTs), in addition to further enhancing their absorption capacity and selectivity, has increased their hydrophilicity, thus minimizing their toxicity and carcinogenic effects. In this scenario, this review aims to provide evidence of both the enormous potential of CNTs in sustainable environmental remediation and the concerning hazards to the environment and living organisms that could derive from their extensive and uncontrolled utilization. To this end, an introduction to CNTs, including their eco-friendly production from biomass, is first reported. Several literature reports on CNTs’ possible utilization for environmental remediation, their potential toxicity due to environmental accumulation and the challenges of their regeneration are provided using several reader-friendly tools, to better capture readers’ attention and make reading easier. Full article

In arid regions, soil salinization and inefficient water use are major challenges to sustainable agricultural development. Optimizing subsurface drainage system layouts is critical for improving saline soil reclamation efficiency. This study conducted field experiments from 2023 to 2024 to evaluate the effects of varying subsurface drainage configurations—specifically, burial depths (1.0–1.5 m) and pipe spacings (20–40 m)—on drainage and salt removal efficiency in silty loam soils of southern Xinjiang, aiming to develop an optimized scheme balancing water conservation and desalination. Five treatments (A1–A5) were established to measure evaporation, drainage, and salt discharge during both spring and winter irrigation. These variables were analyzed using a water balance model and multifactorial ANOVA to quantify the interactive effects of drainage depth and spacing. The results indicated that treatment A5 (1.5 m depth, 20 m spacing) outperformed all the others in terms of both the drainage-to-irrigation ratio (R_d/i) and the drainage salt efficiency coefficient (DSEC), with a two-year average R_d/i of 32.35% across two spring and two winter irrigation events, and a mean DSEC of 3.28 kg·m⁻³. The 1.5 m burial depth significantly improved salt leaching efficiency by increasing the salt control volume and reducing capillary rise. The main effect of burial depth on both R_d/i and DSEC was highly significant (p < 0.01), whereas the effect of spacing was not statistically significant (p > 0.05). Although the limited experimental duration and the use of a single soil type may affect the generalizability of the findings, the recommended configuration (1.5 m burial depth, 20 m spacing) shows strong potential for broader application in silty loam regions of southern Xinjiang and provides technical support for subsurface drainage projects aimed at reclaiming saline soils in arid regions. Full article

The improved multi-stage drip irrigation scheduling, combined with agronomic engineering, was successfully applied for spring re-vegetation in coastal saline soils. To date, few studies have addressed summer vegetation planting using this method. The aim of this study is to reveal the desalinization mechanism associated with summer afforestation and multi-stage drip irrigation. A three-year field experiment was conducted in the coastal saline land of southern China. The trial consisted of four irrigation stages, with the soil moisture potential (SMP) monitored directly beneath the drip emitter at a depth of 0.2 m, correspondingly controlled to be higher than −10 kPa (Stage I), −25 kPa (Stage II), and −45 kPa (Stage III), respectively. Results indicated that soil bulk density decreased by 14%, while soil moisture increased by 30% compared to initial conditions. The average electrical conductivity (EC) value across the entire soil layer decreased by 65.64% to 97.79%. Soil pH gradually increased during the first three irrigation stages, with the rate of increase accelerating during the rainfed stage, reaching values between 9.22 and 9.87. The concentrations of soil ions, including Ca²⁺, K⁺, Mg²⁺, Na⁺, and SO₄²⁻, decreased by 95.18%, 79.67%, 87.74%, 89.68%, and 57.19%, respectively, in the final irrigation stage. Throughout the entire soil profile, the average sodium adsorption ratio (SAR) decreased by 49.37%, while the average exchangeable sodium percentage (ESP) increased by 9.98%. This study demonstrated that multi-stage drip irrigation scheduling significantly influenced the soil physicochemical properties, soil salt ions, and vegetation growth, and thereby explained the efficient desalinization mechanism associated with this irrigation strategy. It is recommended to increase the amount of irrigation water and apply acidic regulators during the rainfed stage to reduce soil pH for vegetation establishment in coastal saline areas. Full article

Coastal saline–alkaline soils are characterized by high salinity and poor permeability. Subsurface drainage and biochar amendment are both practical methods, and their combination may overcome the limitations of individual measures and achieve rapid desalination and soil improvement. To evaluate the impact of different subsurface drainage spacing and biochar amendment on soil properties and crop yield, the salt-tolerant plant “alfalfa” was used as the main material. We designed four drainage spacing treatments (0 m (CK), 6 m (S1), 12 m (S2), and 18 m (S3)) and three biochar amendment rates (5 t ha⁻¹ (C1), 10 t ha⁻¹ (C2), 15 t ha⁻¹ (C3)). Soil physical indicators, salinity, and alfalfa yield are measured. The results showed that smaller drainage spacing and higher biochar amendment rates were beneficial for soil improvement, including bulk density, porosity, and field capacity. The experimental treatments affected the entire soil profile (0–80 cm), with subsurface drainage showing a greater impact on reducing salinity than biochar amendment. The S1 treatment had the most significant yield-increasing effect compared to other spacings. The increase in the biochar amendment rate promoted alfalfa yield, particularly for the first harvest. Overall, the results indicated that the drainage spacing of 6 m and the biochar amendment of 15 t ha⁻¹ were most beneficial in improving soil properties in the plow layer and promoting alfalfa yield in saline–alkaline soils. Full article

Groundwater depth has a significant impact on salinization in irrigated areas. In this study, different groundwater depths were controlled via pit tests and we conducted pit tests with different groundwater depths (DGWs) to investigate the relationship between irrigation water volume and salt migration during the crop growth period, as well as the influence of DGW on maize growth and yield. The aim of this study was to determine an appropriate DGW for maize growth in the Hetao Irrigation District, the largest irrigation area of Asia, under the dual goals of water conservation and salt control. The results showed that the upward replenishment of groundwater was 179.60 mm, 139.17 mm, 119.98 mm, 68.62 mm, and 48.38 mm for each respective DGW, i.e., negatively correlated with DGW during the maize growth period. Soil electrical conductivity (EC) was exponentially related to DGW. For DGWs > 1.75 m, surface soil EC decreased significantly and soil EC exhibited less variation with DGW. Moreover, the desalination rate and depth after irrigation were improved at DGW values of 2.00 m and 2.25 m. Shallow DGW values resulted in increased evapotranspiration and intensified crop stress, which reduced water use efficiency. To reduce resource waste and salt stress on crops, we suggest that a DGW of 2.00~2.25 m is more suitable for maize growth and development. These results provide a reference for determining appropriate DGWs for maize growth in salinized irrigation areas. Full article

Western Kazakhstan is susceptible to desertification, with surface water resource scarcity constraining agricultural development. Groundwater has substantial potential as a reliable and secure alternative to other water resources, particularly for irrigation, which is required to ensure food security. Eight aquifer segments with an exploitable potential of 0.24 km³/year have been identified for the integrated assessment of groundwater’s suitability for irrigation. The assessment criteria included hydro-chemical groundwater characteristics and irrigated land soil-reclamation conditions. The primary objectives of this study were to assess the groundwater quality for irrigation and to develop a practical operation scheme for rational groundwater use in water-saving irrigation technologies and optimize agricultural crop cultivation. Approximately 90% of the groundwater in these aquifer segments was found to be suitable for irrigation, with a total amount of 6520 thousand m³/day and a salinity of up to 1 g/L, and an additional 12,971 thousand m³/day had a water salinity of up to 3 g/L. Only approximately 10% had TDS values above 3 g/L and up to 6.5 g/L, categorized as conditionally suitable for restricted customized agricultural crop irrigation. Irrigated land development by complex soil desalination agro-reclamation operations enabled the use of brackish water for irrigation. The integrated analysis allowed the development of drip irrigation and sprinkling system irrigation schemes that gradually replaced wasteful surface irrigation. The irrigated land prospective area recommended for groundwater irrigation development is 653 km², with the further restructuring of cultivated areas, reducing the number of annual grasses and grain crops and increasing the number of vegetables, potatoes, and perennial grasses. Full article

Halophytes hold significance for soil desalination and co-cultivation in farming systems. A major impediment to their use is the standardization of their performance, since halophytes are mainly wild plants, in addition to the need for a constant supply of the most suitable species. In this work, using highly salt-tolerant clones of Arthrocaulon macrostachyum obtained previously from in vitro micropropagation and selection, we compared the physiological and biochemical responses of these clones and their wild counterparts to high salinity levels (428 mM NaCl) under glasshouse conditions. In vitro-derived clones displayed a superior biomass production (27%) and higher chloride concentration in the shoot (28%), compared to the wild plants. On the other hand, wild specimens showed more stress symptoms and a less efficient photosynthesis, which was correlated with higher levels of oxidative stress and with a remarkable induction of peroxidase activity. Therefore, a higher incidence of salinity-related oxidative stress in the wild halophytes in comparison to the clones is concluded. This represents the first ex vitro evaluation of halophyte clones selected by means of micropropagation and provides insights into the salinity tolerance mechanisms of A. macrostachyum. Full article

Global challenges such as soil degradation and water scarcity necessitate sustainable agricultural practices, particularly in regions where saline water is increasingly used for irrigation. This study investigates the effects of four compost treatments, including surface-applied mulch compost (MC), Johnson–Su biologically active compost incorporated into soil (JCI), mulch compost incorporated into soil (MCI), and no compost as control (NC), on soil fertility, microbial activity, and Capsicum annuum (chili pepper) growth. Greenhouse experiments were conducted using soil from two different sites (New Mexico State University’s (NMSU) agricultural research plots and agricultural field-testing site at the Brackish Groundwater National Desalination Research Facility (BGNDRF) in Alamogordo, New Mexico) and two irrigation water salinities (brackish at ~3000 µS/cm and agricultural at ~800 µS/cm). The Johnson–Su compost treatment demonstrated superior performance, due to its high soil organic matter (41.5%), nitrate (NO₃⁻) content (82.5 mg/kg), and phosphorus availability (193.1 mg/kg). In the JCI-treated soils, microbial biomass increased by 40%, and total microbial carbon reached 64.69 g/m² as compared to 64.7 g/m² in the NC. Plant growth parameters, including chlorophyll content, root length, and wet biomass, improved substantially with JCI. For instance, JCI increased plant height by 20% and wet biomass by 30% compared to NC treatments. The JCI treatment also effectively mitigated soil salinity, reducing Na⁺ accumulation by 60% and Cl⁻ by 70% while enhancing water retention and soil structure. Principal Component Analysis (PCA) revealed a distinct clustering of JCI treatments, demonstrating its ability to increase nutrient retention and minimize salinity stress. These results indicate that biologically active properties, such as fungi-rich compost, are critical to providing an effective, environmentally resilient approach for enhancing soil fertility and supporting sustainable crop production under brackish groundwater irrigation, particularly in regions facing freshwater scarcity. Full article

The salt distribution characteristics in arid areas are directly related to the sustainable development of agriculture. We study the characteristics of spatial changes of soil water and salt in farmland under the full anniversary of different culvert pipe arrangements and optimize the salt drainage parameters of underground drains suitable for the local area so as to promote the management of saline and alkaline land in Xinjiang. A subsurface drainpipe salinity test was conducted in the Yanqi Basin (Bayingoleng Mongolian Autonomous Prefecture, Xinjiang Uygur Autonomous Region, China) to analyze changes in soil water and salt dynamics before and after irrigation-induced salt flushing, assessing the impact of drainpipe deployment parameters. It was found that at a 1.4 m depth of burial, the maximum desalination rates of soil in different soil layers from the subsurface drainpipes in 20, 30, and 40 m spacing plots were 78.28%, 50.91%, and 54.52%, respectively. At a 1.6 m depth of burial, the maximum desalination rates of soil in different soil layers from the subsurface drainpipes in 20, 30, and 40 m spacing plots were 70.94%, 61.27%, and 44.12%. Reasonable deployment of subsurface drainpipes can effectively reduce soil salinity, increase the desalination rate, and improve soil water salinity condition. This study reveals the influence of the laying parameters of subsurface drainpipes on soil water salinity distribution characteristics in arid zones, which provides theoretical support and practical guidance for the management of soil salinization in arid zones. Full article

The yield and quality of rice are influenced by soil conditions, and the soil issues in saline–alkaline land limit agricultural productivity. The saline–alkaline fields in the northern irrigation area of Yinchuan, Ningxia, China, face challenges such as low rice yield, poor quality, low fertilizer utilization efficiency, and soil salinity and alkalinity obstacles. To improve this situation, this study conducted experiments in 2022–2023 in the saline–alkaline rice–crab integrated fields of Tongbei Village, Tonggui Township, Yinchuan. This study employed a single-factor comparative design, applying 150 mL·hm⁻² of brassinolide (A1), 15 kg·hm⁻² of diatomaceous (A2), 30 kg·hm⁻² of Bacillus subtilis agent (A3), and an untreated control (CK) to analyze the effects of different biological amendments on rice growth, photosynthesis, yield, quality, and microbial communities. The results indicated that, compared with CK, the A3 increased the SPAD value and net photosynthetic rate by 2.26% and 28.59%, respectively. Rice yield increased by 12.34%, water use efficiency (WUE) by 10.67%, and the palatability score by 2.82%, while amylose content decreased by 8.00%. The bacterial OTUs (Operational Taxonomic Units) and fungal OTUs increased by 2.18% and 22.39%, respectively. Under the condition of applying 30 kg·hm⁻² of Bacillus subtilis agent (A3), rice showed superior growth, the highest yield (8804.4 kg·hm⁻²), and the highest microbial OTUs. These findings provide theoretical and technical support for utilizing biological remediation agents to achieve desalinization, yield enhancement, quality improvement, and efficiency in saline–alkali rice–crab co–culture paddies. Full article