Search Results (109)

Subsurface drainage and biochar application are conventional measures for improving saline–alkali soils. However, their combined effects on the fate of nitrogen (N) fertilizers remain unclear. This study investigated the combined effects of subsurface drainage and biochar amendment on the fate of nitrogen (N) in coastal saline–alkali soils, where these conventional remediation measures’ combined impacts on fertilizer N dynamics remain seldom studied. Using ¹⁵N-labeled urea tracing in an alfalfa–soil system, we examined how different drainage spacings (0, 6, 12, and 18 m) and biochar application rates (5, 10, and 15 t/ha) influenced N distribution patterns. Results demonstrated decreasing in drainage spacing and increasing in biochar application; these treatments enhanced ¹⁵N use efficiency on three harvested crops. Drainage showed more sustained effects than biochar. Notably, the combination of 6 m drainage spacing with 15 t/ha biochar application achieved optimal performance of ¹⁵N use, showing N utilization efficiency of 46.0% that significantly compared with most other treatments (p < 0.05). ¹⁵N mass balance analysis revealed that the plant absorption, the soil residual and the loss of applied N accounted for 21.6–46.0%, 38.6–67.5% and 8.5–18.1%, respectively. These findings provide important insights for optimizing nitrogen management in coastal saline–alkali agriculture, demonstrating that strategic integration of subsurface drainage (6 m spacing) with biochar amendment (15 t/ha) can maximize N use efficiency, although potential N losses warrant consideration in field applications. Full article

Groundwater serves as a vital resource for sustainable water supply, particularly in semi-arid regions where surface water availability is limited. This study explores groundwater potential zones in the East Desert, Qift–Qena, Egypt, using a multidisciplinary approach that integrates remote sensing (RS), geographic information systems (GIS), geostatistics, and field validation with water wells to develop a comprehensive groundwater potential mapping framework. Sentinel-2 imagery, ALOS PALSAR DEM, and SMAP datasets were utilized to derive critical thematic layers, including land use/land cover, vegetation indices, soil moisture, drainage density, slope, and elevation. The results of the groundwater potentiality map of the study area from RS reveal four distinct zones: low, moderate, high, and very high. The analysis indicates a notable spatial variability in groundwater potential, with “high” (34.1%) and “low” (33.8%) potential zones dominating the landscape, while “very high” potential areas (4.8%) are relatively scarce. The limited extent of “very high” potential zones, predominantly concentrated along the Nile River valley, underscores the river’s critical role as the primary source of groundwater recharge. Moderate potential zones include places where infiltration is possible but limited, such as gently sloping terrain or regions with slightly broken rock structures, and they account for 27.3%. These layers were combined with geostatistical analysis of data from 310 groundwater wells, which provided information on static water level (SWL) and total dissolved solids (TDS). GIS was employed to assign weights to the thematic layers based on their influence on groundwater recharge and facilitated the spatial integration and visualization of the results. Geostatistical interpolation methods ensured the reliable mapping of subsurface parameters. The assessment utilizing pre-existing well data revealed a significant concordance between the delineated potential zones and the actual availability of groundwater resources. The findings of this study could significantly improve groundwater management in semi-arid/arid zones, offering a strategic response to water scarcity challenges. 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

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

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

The salinization of cultivated soil in arid zones is a core obstacle restricting the sustainable development of agriculture, particularly in regions like Xinjiang, China, where extreme aridity and intensive irrigation practices exacerbate salt accumulation through evaporation–crystallization cycles. Conventional drip irrigation, while temporarily mitigating surface salinity, often leads to secondary salinization due to elevated water tables and inefficient leaching. Recent studies highlight the potential of integrating drip irrigation with subsurface drainage systems to address these challenges, yet the synergistic mechanisms governing ion transport dynamics, hydrochemical thresholds, and their interaction with crop physiology remain poorly understood. In this study, we analyzed the effects of spring irrigation during the non-fertile period, soil hydrochemistry variations, and salt ion dynamics across three arid agroecosystems in Xinjiang. By coupling drip irrigation with optimized subsurface drainage configurations (burial depths: 1.4–1.6 m; lateral spacing: 20–40 m), we reveal a layer-domain differentiation in salt migration, Cl⁻ and Na⁺ were leached to 40–60 cm depths, while SO₄²⁻ formed a “stagnant salt layer” at 20–40 cm due to soil colloid adsorption. Post-irrigation hydrochemical shifts included a 40% decline in conductivity, emphasizing the risk of adsorbed ion retention. Subsurface drainage systems suppressed capillary-driven salinity resurgence, maintaining salinity at 8–12 g·kg⁻¹ in root zones during critical growth stages. This study establishes a “surface suppression–middle blocking–deep leaching” three-dimensional salinity control model, providing actionable insights for mitigating secondary salinization in arid agroecosystems. Full article

Karst aquifers can be highly productive water sources but are vulnerable to contamination by pathogens because of integrated surface and subsurface drainage. Our study focuses on the karstic Royal Spring basin in Kentucky, encompassing urban and agricultural land uses. The city of Georgetown distributes treated water from Royal Spring to over 33,000 customers. We examined E. coli dynamics at Royal Spring from June 2021 through June 2022, assessing variability under wet versus dry weather conditions. We also used quantitative microbial risk assessment (QMRA) to estimate potential health risks from the pathogenic bacterium E. coli O157:H7. E. coli concentrations in weekly water samples varied from 12 to 1732.8 MPN/100 mL, with a geometric mean of 117.2 MPN/100 mL. The mean concentration in wet periods was approximately double that during dry conditions. Because the pathogen was not detected by quantitative PCR (qPCR), we conducted QMRA based on literature data for water treatment plant operations (occupational) and recreational activities near the spring. The median probability of annual infection was 5.11 × 10⁻³ for occupational exposure and 1.45 × 10⁻² for recreational exposure. Uncertainty and sensitivity analyses revealed that health risks were most sensitive to the pathogen/E. coli ratio and ingestion rate. Although the pathogen was not detected by qPCR, the presence of E. coli suggests potential fecal contamination. This highlights the importance of continued monitoring and investigation of different detection methods to better understand potential health risks in karst systems. Full article

This study presents the effectiveness of two vertical subsurface flow (VF) constructed wetlands (CWs), one planted with Juncus effusus (PCW) and the other unplanted (CCW), for the remediation of acid mine drainage (AMD) from the Ouixane abandoned mine site located in Morocco. The VFs were fed with highly acidic AMD (pH < 2.5) and were evaluated over a period of 150 days. The substrate was composed of limestone, as a neutralizing agent, river gravel, and natural peat moss, with the goal of promoting the growth of sulfate-reducing bacteria (SRB) and metals precipitation. The results showed that both VFs successfully neutralized the acidity, with effluent pH values ranging from 3.57 to 8.5, indicating effective alkalinization of the AMD. Significant differences (p < 0.05) were observed between the metal removal rates of the CCW and the PCW, except for Mn. Both types of constructed wetlands (CWs), the planted system (PCW) and the unplanted system (CCW), exhibited similar efficiencies in metal removal from the influent. The rates of metalloid removal were as follows: 99.9% vs. 99% for Cr, 99% vs. 80% for As, 96% vs. 94 for Zn, 99.94% vs. 99% for Fe, and 90% vs. 81% for Al. Microbial sulfate reduction was increased from 43% to 50% by the presence of plants. Sediment analysis revealed that metals were primarily in stable forms: Fe and Zn were mostly associated with Fe-Mn oxides, while Mn and Ni were predominantly present as carbonates. These observations indicate a relative stability of metals in the CWs’ sediment. This study highlights the effectiveness of the studied CWs, particularly those with vegetation, for AMD remediation, emphasizing the importance of neutralizing agents, plants, and organic substrates in the treatment process. Full article

Drainage is an important aspect of effective water management in row-crop agriculture. Drainage systems can be broadly categorized as either subsurface or surface drainage. A significant amount of design goes into subsurface drainage installations, such as tile networks, and permanent surface drainage installations, such as waterways and berms. However, many farmers also implement temporary surface drainage installations to drain localized areas within their fields each year. This practice involves creating shallow water paths, typically using spinner ditchers, and it is especially commonplace in areas with poor soil permeability. However, this practice is traditionally performed using only observations by farmers and without any data-based workflows. The objective of this study was to analyze the potential yield benefits from a more data-informed approach to surface drainage on a production row-crop farm by exploring corn and soybean yield data from 2008–2021 from two fields where a data-informed approach to surface drainage was implemented. Field topography and drainage information were combined with yield maps from prior years with traditional ad hoc drainage and the years following the incorporation of the data-informed approach to better understand the impact of the workflow. Geospatial distribution of the average normalized crop yields and elevation maps for the fields were analyzed to isolate the yield impacts of the areas affected by the data-informed on-farm surface drainage artifacts. In the years after implementation of the data-informed surface drainage approach, Field 1 and Field 2 showed respective increases of 18.3% and 13.9% in average corn yields. Further analysis isolating three areas affected by the surface drainage using topography and drainage layout showed that all three isolated areas improved more than the field averages, ranging from 15.9–26.5% for Field 1 and 21.4–40.2% for Field 2. Similarly, soybean yields were also higher in the isolated affected areas after the data-informed drainage ditch construction. The findings highlight the effectiveness of data-informed on-farm surface drainage, a relatively straightforward approach that proved beneficial for both soybean and corn production. Full article

Citrus trees, particularly oranges, are a highly significant plant genus due to their consumption as fresh produce and the multiple compounds derived from them, which are extensively used in the food, cosmetic, and pharmaceutical industries. Despite recent advancements, the understanding of metabolic processes in the Citrus genus remains limited, especially in the context of variable agricultural practices. This study aimed to investigate the metabolomic evolution in leaves of sweet orange (Citrus sinensis) cultivated under different conditions over two key developmental periods: pre-winter (t₁) and spring sprouting and flowering (t₂). Using proton nuclear magnetic resonance (H-NMR) spectroscopy, this research identified 27 key metabolites across five distinct cultivation treatments (T0, T1, T2, T3, T4), including amino acids, organic acids, and sugars, and their variation over time. T0 represents the traditional crop of the control plot, while T1, T2, T3, and T4 incorporate different strategies aimed at water-saving, such as the use of weed control mesh and subsurface drainage systems, all designed to improve profitability and crop efficiency under the same soil and climatic conditions. The treatments were evaluated for their impact on plant growth parameters such as height, trunk diameter, and flower production, with a focus on reducing water usage without compromising crop performance. The results indicate that the use of weed control mesh significantly improves plant growth, increases flower production, and stabilizes key metabolite levels, contributing to a concept termed “plant metabolomic homeostasis.” These findings are particularly relevant in regions like southeastern Spain, where water scarcity is a major concern. The study provides compelling evidence that the implementation of weed control mesh in orange cultivation can enhance water efficiency, promote healthier plant development, and maintain metabolic stability under variable growing conditions. These results suggest that such agricultural practices could be recommended for broader commercial application in citrus cultivation to improve sustainability and crop profitability. Full article

Subsurface (or tile) drainage offers a valuable solution for enhancing crop productivity in poorly drained soils. However, this practice is also associated with significant nutrient leaching, which can contribute to water quality problems at the regional scale. This research presents the findings from a 4-year tile depth and spacing study in central Illinois that included three drain spacings (12.2, 18.3, and 24.4 m) and two drain depths (0.8 and 1.1 m) implemented in six plots under the corn and soybean rotation system (plots CS-1 and CS-3: 12.2 m spacing and 1.1 m depth, plots CS-2 and CS-4: 24.4 m spacing and 1.1 m depth, and plots CS-5 and CS-6 18.3 m spacing and 0.8 m depth). Our observations indicate that drain flow and NO₃-N losses were higher in plots with narrower drain spacings, while plots with wider drain spacing showed reduced drain flow and NO₃-N losses. Specifically, plots set up with drain spacings of 18.3 m and 24.4 m showed significant reductions in drain flow compared to plots featuring a 12.2 m drain spacing. Likewise, plots characterized by 18.3 m and 24.4 m drain spacings (except CS-4) showed better NO₃-N retention and lower leaching losses than those with 12.2 m spacing (CS-1 and CS-3). Crop yield results over a 3-year period indicated that CS-2 (wider spacing plot) showed the highest productivity, with up to 13.6% higher yield compared to other plots. Furthermore, when comparing plots with the same drainage designs, CS-2 and CS-4 showed 5.1% to 2.6% higher corn yield (3-year average) compared to CS-1 and CS-3, and CS-5 and CS-6, respectively. Overall, a wider drainage system showed the capacity to export lower nutrient levels while concurrently enhancing productivity. These findings represent that optimizing tile drainage systems can effectively reduce nitrate losses while increasing crop productivity. Full article

In South Korea, paddy fields are increasingly being planted with soybeans to address rice supply and demand issues and increase soybean self-sufficiency. The field crops cannot grow healthily without adequate drainage due to the paddy fields storing water easily. In this study, we identified that Rice Husk Filling Drainage Method (RHDM) technology improved soil permeability and soil aeration. We also found that the soil moisture content was reduced and the water table remained at a lower level in the RHDM plot as compared to the control plot. The soybean moisture stress index showed that in the RHDM plot, the safety standard for stress due to excessive moisture at the 2 m interval was met. The soybean yield was increased by up to 35% in the 2 m RHDM construction interval compared to the control plot. In addition, the high hydraulic conductivity of the rice husk used as the hydrophobic material confirmed sufficient drainage performance and was considered economically advantageous. Therefore, our results show that RHDM is a highly efficient and economical drainage method in poorly drained paddy soils. Drainage management is essential for stable crop production in poorly drained paddy fields. Our research findings suggest that an efficient open field water management method is viable, which we believe will lead to future advances in open field smart agriculture. Full article

Combined heavy mineral analysis and detrital zircon geochronology have enabled us to track detritus supplied by the ancestral river systems draining the North American continent into the deep subsurface of the Gulf of Mexico, in both the coastal plain and the offshore deep water areas. During deposition of the Paleocene–Eocene Wilcox Group, sandstones in the western part of the area are interpreted as the products of the Rosita system derived via paleo-Rio Grande material, with a large component of sediment shed from the Western Cordillera. By contrast, samples from wells further east have high proportions of zircons derived from the Yavapai-Mazatzal Province and are attributed to the Rockdale system with sediment fed predominantly by the paleo-Colorado or paleo-Colorado-Brazos. There is evidence that sediment from the Rosita system occasionally extended into the central Gulf of Mexico, and, likewise, data indicate that the Rockdale system sporadically supplied sediment to the western part of the basin. During the Late Eocene of the central Gulf of Mexico (Yegua Formation) there was a distinct shift in provenance. The earlier Yegua sandstones have a large Grenville zircon component and are most likely to have had a paleo-Mississippi origin, whereas the later Yegua sandstones are dominated by zircons of Western Cordilleran origin, similar to Wilcox sandstones fed by the Rosita system via the paleo-Rio Grande. The switch from paleo-Mississippi to paleo-Rio Grande sourcing implies there was a major reorganisation of drainage patterns during the Late Eocene. Miocene sandstones in the deepwater Gulf of Mexico were principally sourced from the paleo-Mississippi, although the paleo-Red River is inferred to have contributed to the more westerly-located wells. Full article

Groundwater resources are essential for sustaining ecosystems and human activities, especially under the pressures of climate change. This study employed Electrical Resistivity Tomography (ERT) to assess the impact of Gully Land Consolidation (GLC) engineering on the groundwater hydrological field of small watersheds in the China Loess Plateau (CLP). Results revealed ample subsurface water storage in backfilled areas, primarily migrating along the original river path owing to topographical limitations. Although the distribution patterns of soil moisture in each backfilling block varied slightly, the boundaries of soil moisture content and variation mainly appeared at depths of 8 m and 20 m underground. Significant moisture variation occurred across the 0–20 m underground layers, suggesting the 8–20 m layer could function as a groundwater collection zone in the study area. Human activities could disturb groundwater, altering migration pathways from the original river path. An optimized “Drainage–Conveyance–Barrier” system is proposed to enhance GLC sustainability, involving upstream groundwater level control, midstream soil moisture management, and downstream hydrological connectivity improvement. These findings carry substantial implications for guiding the planning and execution of GLC engineering initiatives. The novelty of this study lies in its application of ERT to provide a detailed spatial and temporal understanding of soil moisture dynamics in the GLC areas. Future research should focus on factors such as soil types and topographical changes for a comprehensive assessment of GLC’s impact on small watershed groundwater hydrology. Full article

Drainage water management (DWM), also known as controlled drainage (CD), is one of the edge-of-field strategies mainly designed to reduce the nitrate load from subsurface drainage systems. By limiting runoff, we also increase local retention, contributing to the sustainable management of water resources. For that purpose, CD involves using different kinds of controlled drainage devices. They are usually based on simple flashboard risers or stop-logs that regulate the drainage intensity by raising and lowering the drainage outlet. The problem with this type of device is the need for manual control, which can cause the CD system to be more demanding in terms of maintenance. A new approach to water management by CD allows the possibility of individual disassembly of each board without necessarily removing all of them. Thanks to the use of sideling runners, the water management process is much quicker. This is especially important when a farmer needs to manage water in a few controlled drainage devices in the field. The different variants of the design are shown here, as well as the way of stop-log assembly and control and the costs of maintaining similar devices. The advantages and disadvantages are described, and the usefulness of the new patented solution is assessed. Full article