Search Results (126)

The Subsurface self-regulating, Low-Energy, Clay-based Irrigation (SLECI) system is a recently developed irrigation method. The SLECI system supplies water directly to the crop root zone by utilising the potential difference established between its permeable interior and exterior radial walls. In this study, we investigated the effect of the SLECI emitter’s operating pressure head and burial depth on the water flow characteristics in sandy loam soil. The results show that the developed COMSOL-2D model accurately predicted water flow characteristic under SLECI. The operating pressure head significantly influenced the water flow characteristics. As the operating pressure head increased, emitter discharge increased, and the wetted soil area was extended. The burial depth had a minimal effect on the emitter discharge but notably affected the advancement and time at which wetting fronts reached the soil surface and bottom boundaries. Operating the SLECI emitter at a higher operating pressure head and shallower burial depth could degrade irrigation water application and water use efficiencies. Based on a multi-objective optimisation algorithm, we recommend that the SLECI emitter be operated at a 125 cm pressure head and buried at 40 cm for crops with a root zone depth of 100 cm. Our study is expected to provide a greater understanding of the SLECI system and offer some recommendations and guidelines for its efficient deployment in sandy loam for enhanced water use efficiency in crop production. Full article

The increasing water demand, fueled by rapid development activities, has significantly strained freshwater reservoirs. A comprehensive study was conducted in the Anantnag district of Jammu and Kashmir to determine the discharge rates of key water springs and assess their capacity to meet the crop water requirements within their respective command areas. The research focused on seven vital springs—Martand, Achabal, Malakhnag, Sherbagh, Verinag, Lukhbawan, and Kokernag—which are critical for domestic and agricultural purposes. The study was carried out from May to October 2018, employed the weir formula to measure spring discharge, and utilized evapotranspiration (ETo) calculations, integrating evaporation and rainfall data to estimate crop water requirements. The results revealed significant variability in spring discharge rates, with Verinag spring being the most productive at 4.55 m³/s, followed by Sherbagh at 1.97 m³/s, while Lukhbawan exhibited the lowest discharge rate at 0.17 m³/s. Springs such as Verinag, Martand, and Achabal demonstrated sufficient capacity to meet the water demands of crops in their command areas, highlighting their potential for sustainable agricultural support. These findings emphasize the importance of integrating surface–subsurface water dynamics in water resource management to ensure efficient utilization of these springs for both domestic and irrigation needs. The study provides valuable insights into optimizing spring water use to address increasing water demands in the region, contributing to sustainable development and resource conservation. Full article

Quantifying changes in soil properties greatly benefits our understanding of soil management and sustainable land use, especially in the context of strong anthropogenic activities and climate change. This study investigated the effects of long-term reclamation on soil properties in an artificial oasis region with a cultivation history of more than 50 years. Critical soil properties were measured at 77 sites, and a total of 462 soil samples were collected down to a depth of 1 m, which captures both surface and subsurface processes that are critical for long-term cultivation effects. Thirteen critical soil properties were analyzed, among which four properties—soil organic carbon (SOC), total phosphorus (TP), pH, and ammonium nitrogen (NH₄⁺)—were selected for detailed analysis due to their ecological significance and low intercorrelation. By comparing cultivated soils with nearby desert soils, this study found that semicentennial cultivation led to significant improvements in soil properties, including increased concentrations of SOC, NH₄⁺, and TP, as well as reduced pH throughout the soil profile, indicating improved fertility and reduced alkalinity. Further analysis suggested that environmental factors—including temperature, clay content, evaporation differences between surface and subsurface layers, sparse vegetation cover, cotton root distribution, as well as prolonged irrigation and fertilization—collectively contributed to the enhancement of SOC decomposition and the reduction of soil alkalinity. Furthermore, three-dimensional digital soil mapping was performed to investigate the effects of long-term cultivation on the distributions of soil properties at unvisited sites. The soil depth functions were separately fitted to model the vertical variation in the soil properties, including the exponential function, power function, logarithmic function, and cubic polynomial function, and the parameters were extrapolated to unvisited sites via the quantile regression forest (QRF), boosted regression tree, and multiple linear regression techniques. The QRF technique yielded the best performance for SOC (R² = 0.78 and RMSE = 0.62), TP (R² = 0.79 and RMSE = 0.12), pH (R² = 0.78 and RMSE = 0.10), and NH₄⁺ (R² = 0.71 and RMSE = 0.38). The results showed that depth function coupled with machine learning methods can predict the spatial distribution of soil properties in arid areas efficiently and accurately. These research conclusions will lead to more effective targeted measures and guarantees for local agricultural development and food security. 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

This study employed the HYDRUS-2D model to simulate soil water movement and water productivity (WP) in an apple–soybean alley cropping system in the Loess Plateau region, Shanxi Province, China, under four irrigation methods: mulched drip irrigation, subsurface drip irrigation, bubbler irrigation, and rainwater-harvesting ditch irrigation, with varying water management treatments. Field experiments provided 2022 data for model calibration and 2023 data for validation using soil water content (SWC) measurements, achieving R² = 0.80–0.87 and RMSE = 0.011–0.017 cm³·cm⁻³, confirming robust simulation accuracy. The simulation results indicated that different irrigation methods had a significant impact on the soil water distribution. Mulched drip irrigation enhanced the water content in the surface layer (0–20 cm), while subsurface drip irrigation increased the moisture in the middle soil layer (20–40 cm). Bubbler irrigation was most effective in replenishing both the surface (0–20 cm) and middle (20–40 cm) layers. Rainwater-harvesting ditch irrigation significantly improved the soil water content in both the surface (0–20 cm) and middle (20–40 cm) layers, with minimal changes observed in the deep layer (40–120 cm). Furthermore, soil water variations were significantly influenced by the water uptake of tree roots. In 2022, soil moisture initially increased with distance, then decreased, and subsequently increased again, while in 2023, it increased initially and then stabilized. When the irrigation amount was limited to 75% of the field capacity in the 0–60 cm soil layer, water productivity (WP) reached its optimum, with values of 4.79 kg/m³ (2022) and 5.56 kg/m³ (2023). Based on the simulation results, it is recommended that young apple trees be irrigated using subsurface drip irrigation with a soil layer depth of 30 cm, while soybeans should be irrigated with mulched drip irrigation. Both crops should be irrigated at the podding and filling stages of soybeans, and the irrigation amount should be limited to 75% of the field water capacity in the 0–60 cm soil layer. This study was designed to aid orchard growers in precision irrigation and water optimization. Full article

China is one of the countries most seriously affected by soil salinization, while the impact of salt-controlled irrigation on the relationship between soil dissolved organic matter (DOM) and microbial in farmland affected by salinization remains largely unexplored. We conducted a comprehensive survey of soil DOM and a microbial survey of Ordos’s salinized farmland in China before and after salt-controlled irrigation. Our findings reveal a reduction of 18.4 mg/L in surface soil (0–10 cm) DOC following irrigation, whereas the subsurface soil (20–40 cm) DOC increased by 20.7 mg/L. Moreover, irrigation led to an increase in the aromaticity and humification of the soil, with the salt content of the subsurface soil rising from 2.7 to 3.7 mg/g. Additionally, the total dissolved solids (TDS) in the drained water were 2463 mg/L higher than in the irrigation water (1416.3 mg/L). This suggests that the DOM and salts from the surface soil either leached into deeper layers or were lost via runoff. Furthermore, SEM analysis and a Mantel test revealed that microbial composition significantly influenced soil DOM contents, especially increased levels of Marmoricola and MND1, which are associated with decomposing organic matter and may contribute to the leaching of soil DOM in deep layers following irrigation. Full article

The objectives of this study were to determine the effects of irrigation method on the movement of 10 commonly used pesticides in container nursery production. Pesticide transport under three irrigation methods at a nursery engineered to collect irrigation return flow (IRF) from the production surface and subsurface was determined. Pesticide applications occurred three times throughout the study, followed by a 16-day monitoring period. The irrigation applied and surface and subsurface IRF volumes generated from single irrigation events were measured and subsamples of the IRF water were analyzed to assess pesticide presence. Overhead irrigation served as the control with two microirrigation treatments, one applying a fixed amount of water each day and the other scheduled using substrate moisture sensors. Microirrigation reduced irrigation volume by >75% and surface IRF by up to 100%. Subsurface IRF was similarly reduced by microirrigation, yielding 23–47% lower volumes. Pesticides with greater solubilities and lower adsorption coefficients were more mobile than the inversely characterized compounds, particularly in subsurface IRF. The least soluble pesticides had a reduced presence in surface and, to a larger extent, subsurface IRF. Reductions or elimination of surface IRF by using microirrigation reduced the transport of all pesticides by >90%. Pesticides that had a higher solubility were found in subsurface IRF regardless of irrigation method. This study demonstrates the importance of both the irrigation delivery method and pesticide physiochemical properties on the environmental fate of pesticides in nursery settings. Microirrigation can reduce and often eliminate surface IRF, limiting the movement of pesticides regardless of physiochemical properties; whereas, the selection of pesticides that are less soluble can be an effective way to limit the subsurface movement of pesticides, regardless of irrigation method. Full article

Unsustainable groundwater extraction for domestic and agricultural purposes, particularly crop irrigation, is leading to dramatic reductions in the quantity and quality of groundwater in many developing countries, including Ethiopia. Assessing and predicting groundwater responses to hydraulic stress caused by overexploitation related to anthropogenic activities and climate change are crucial for informing water management decisions. The aim of this study is to develop a three-dimensional steady-state groundwater flow model for the Golina River Sub-Basin to understand the relationship between groundwater recharge and groundwater pumping and their impacts under steady-state conditions from the perspective of groundwater management. The model was created using MODFLOW 6 and discretized into 345 rows and 444 columns with a grid resolution of 100 m by 100 m. The subsurface was modeled as two layers: a clastic alluvial layer overlying a weathered and fractured bedrock. The surface-water divide of the Golina River Sub-Basin was treated as a no-flow boundary. The initial values of horizontal hydraulic conductivity ranged from 0.001 m/day for rhyolite to 27.26 m/day for alluvial deposits. The aquifer recharge rates from the WetSpass model ranged from 1.08 × 10⁻³ to 2.25 × 10⁻⁴ m/day, and the discharge rates from the springs, hand-dug wells, and boreholes were 2.79 × 10⁴ m³/day, known flux boundaries. Sensitivity analysis revealed that the model is very sensitive to hydraulic conductivity, moderately sensitive to aquifer recharge, and less sensitive to groundwater pumping. Calibration was performed to match observed and simulated hydraulic heads of selected wells and achieved a correlation coefficient of 0.998. The calibrated hydraulic conductivity ranged from 1.2 × 10⁻⁴ m/day for rhyolite to 20 m/day for gravel-dominated alluvial deposits. The groundwater flow direction is toward the southeast, and the water balance indicates a negligible difference between the total recharge (207,775.8297 m³/day, which is the water entering the aquifer system) and the total pumped volume (207,775.9373 m³/day, which is the water leaving the aquifer system). The scenario analysis showed that an increase in the pumping rate of 25%, 50%, and 75% would result in a decrease in the hydraulic head by 4.64 m, 10.18 m, and 17.38 m, respectively. A decrease in recharge of 25%, 50%, and 75% would instead result in hydraulic-head declines of 6 m, 15.29 m, and 46.97 m, respectively. Consequently, the findings of this study suggest that decision-makers should prioritize enhancing integrated groundwater management strategies to improve recharge rates within the aquifer system of the study area. Full article

Coordinating the spatial distribution of crop roots with soil nutrients, along with selecting appropriate types of fertilizers, is an effective strategy to enhance root nutrient absorption and increase crop yield. In Xinjiang’s current surface drip irrigation practices for rice (Oryza sativa L.), premature leaf senescence and N deficiency are common issues, resulting in decreased yields. This study investigated whether different N forms under subsurface drip irrigation can modulate rice root morphological strategies to delay senescence in later growth stages, enhancing rice N uptake and yield formation. A field experiment compared the effects of different drip irrigation positions (surface drip irrigation at the surface, DI0; subsurface drip irrigation at 10 cm depth, DI10) and N forms (urea N, UN; ammonium N, AN) in four combination treatments (DI0-UN, DI0-AN, DI10-UN, DI10-AN) on rice root morphology, aboveground growth, and yield formation. During the grain-filling stage, the total root length (RL) and root number (RN) in the DI10-AN treatment were higher than in other treatments. Root vitality increased by 23.24–133.72% during the later filling stages, while the root decline rate decreased by 1.16–32.80%. The root configuration parameters β in the DI10-AN treatment were superior to those in other treatments, indicating that roots tend to distribute deeper in the soil. The DI10-AN treatment reduced Malondialdehyde (MDA) levels and increased Superoxide Dismutase (SOD) activity, thereby alleviating water and N stress on the leaves in later growth stages and maintaining higher photosynthetic parameter values. The DI10-AN treatment significantly increased N absorption (14.37–52.88%) and yield (13.32–46.31%). Correlation analysis showed that RL, RN, and root activity (Ra) were significantly positively correlated with transpiration rate (Tr), intercellular CO₂ concentration (Ci), N uptake (NUP), one thousand-kernel weight (TKW), seed setting rate (SR), Efficient panicle (EP), and yield (r > 0.90). This study presents a new rice drip fertigation technique that combines subsurface irrigation with ammonium to enhance root growth and increase crop productivity. Full article

This study investigates the effect of the spatial distribution of soil water and nutrients on cork oak (Quercus suber) architecture. Fertirrigation is being tested in cork oak plantations to accelerate tree growth up to the production stage. To assess the impact of wet bulb location on tree development, six trees (three subjected to subsurface drip irrigation and three controls) were fully excavated at a sandy soil site, along with a seventh tree subjected to surface drip irrigation at a sandy loam soil site. The aerial parts of the trees were digitized using a Polhemus Fastrak magnetic digitizer and segmented into orders starting from the main trunk. Roots with diameters greater than 0.5 cm were digitized during excavation and segmented by size and order from the root collar. For each segment, length, orientation, and spatial location were calculated. General linear models were then applied to compare total root length across orientation and quadrant classes. Crown architecture was influenced by factors such as light competition. Irrigation treatments did not significantly affect root architecture when wet bulb formation was constrained. However, tree no. 7 had 50% of its total root length located within the wet bulb quadrant. These findings suggest that differences in soil type and irrigation method influence wet bulb formation, potentially reducing the impact of fertirrigation on root architecture. Strategies to minimize tree dependence on wet bulb zones are crucial for enabling future irrigation suppression. Full article

The Mediterranean region faces intensified climate change effects, increasing irrigation demands to sustain crop yields and increasing pressure on water resources. Adaptive management strategies such as conservation agriculture (CA) offer potential benefits for soil quality and water use efficiency. However, there is limited research on the short-term effects of this farming system under irrigated Mediterranean climatic conditions. This study aimed to explore the short-term impacts of conservation agriculture (no tillage, cover crops and crop rotation) on the soil properties, water flows and crop and water productivity in a French Mediterranean agrosystem of irrigated field crops, using a multifactorial approach. From 2021 to 2023, maize, sorghum and soybean were grown successively under either conventional tillage (CT) or conservation agriculture (CA), combined with sprinkler irrigation, subsurface drip irrigation or non-irrigated conditions. The dynamics of the surface soil properties (bulk density, penetration resistance, soil temperature), water flows (infiltration, soil evaporation) and agronomic indicators (leaf area index, crop yield, water productivity) were measured across the three cropping seasons. In the pedoclimatic conditions of the study, CA was shown to clearly impact the soil properties, water flows and crop yields, from the first year of adoption. CA practices caused an increased bulk density and soil resistance penetration, leading to decreased quasi-steady ponded infiltration in the surface horizon, particularly in the CA–subsurface drip and CA–non-irrigated conditions. These effects were also reflected in the leaf area index, crop yield and water productivity, with CA showing lower values compared to CT. Crop residues in CA reduced soil evaporation, particularly under sprinkler irrigation. However, this benefit diminished as the residues decomposed, leading to soil evaporation rates comparable to those observed in CT. Agronomic indicators were better under sprinkler irrigation than under subsurface drip irrigation. Overall, compaction emerged as a significant challenge in the adoption of CA, considering its negative impact on crop yields. Full article

The interaction between surface water and groundwater has been extensively studied due to its water management implications and the potential environmental impacts arising from it. Experimental studies and numerical modeling have supported analytical solutions; these solutions have been proposed for specific cases in which the aim has been to understand discharge/recharge and aquifer characterization. In this study, new graphical solutions or type curves are provided to estimate the subsurface flow and thermal–mechanical parameters in anisotropic porous media. Using the non-dimensionalization technique of the governing equations, new dimensionless groups (lumped parameters) that govern the solution of both the mechanical problem (uncoupled) and the thermal problem are obtained. From these groups, and by applying the pi theorem and examining numerical simulations of numerous cases, user-friendly type curves are obtained. The recharge flow and hydraulic conductivity are calculated when the thermal properties, geometrical parameters, and temperature variables are known. To evaluate the reliability of the type curves, two real case studies are presented: the interaction between the Guadalfeo River and the Motril-Salobreña coastal aquifer, and the artificial recharge program in the coastal aquifer of Agua Amarga in southern Spain. For verification, the groundwater flow obtained from the type curves is compared with the recharge data. In the case of the river–aquifer interaction, the recharge flow obtained is 13% less than that estimated in previous studies. Regarding the artificial recharge of the coastal aquifer, the flow obtained is 21% less than the volume irrigated over the salt marsh. The uncertainties related to hydrogeological features are considered to have the greatest influence on the error. Full article

The aim of this study is to construct and validate an expert system to predict the adaptation of irrigation technologies, water-saving strategies, and monitoring tools by small-scale farmers in Egypt. The research investigates the impact of economic, educational, environmental, and social factors on adaptation rates. To build the expert system, extensive knowledge was collected from experts, key concepts were identified, and production rules were created to generate tailored scenarios. These scenarios utilize the empirical cumulative distribution function (ECDF), selecting the scenario with the highest ECDF as the optimal irrigation technology. This approach ensures well-informed, data-driven decisions that are tailored to specific conditions. The expert system was evaluated under the conditions of ten small farms in Egypt. The results indicate that water cost and availability are significant drivers of technology adaptation. Specifically, subsurface drip irrigation (SDI) demonstrated an adaptation percentage of 75% at high water costs, with probabilities of 0.67 and 0.33, while soil mulching (SM) showed a 75% adaptation rate with a probability of 0.33 in high-cost scenarios. Conversely, when water availability was high, the adaptation percentage for all techniques was zero, but it reached 100% adaptation with a probability of 0.76 for SM and SDI and a probability of 1 for variable number of drippers (VND) and the use of sensors as monitoring tools during water shortages. Educational attainment and professional networks enhance the adaptation of advanced technologies and monitoring tools, emphasizing the role of knowledge and community engagement. Environmental conditions, including soil texture and salinity levels, directly affect the choice of irrigation methods and water-saving practices, highlighting the need for localized solutions. The source of irrigation water, whether groundwater or surface water, influences the preference for water-saving technologies. The study underscores the importance of tailored approaches to address the challenges and opportunities faced by small farmers in Egypt, promoting sustainable agriculture and efficient water management. The evaluation findings reveal that SDI is the most favored irrigation technology, with a probability of 0.55, followed by variable number of drippers (VND) at 0.38 and ultralow drip irrigation (ULDI) at 0.07 across various scenarios for small farmers. Regulated deficit irrigation (RDI) and SM are equally preferred water-saving strategies, each with a probability of 0.50. Sensors emerged as the preferred monitoring tool, boasting a high probability of 0.94. The analysis reveals the critical roles of economic pressures, educational levels, environmental conditions, and social networks in shaping the adaptation of sustainable agricultural practices. Full article

A field experiment was conducted on sunflowers in a mild-to-moderate saline–alkaline area in the Tumochuan Plain irrigation region in China. The experimental design included using surface drip irrigation as a control (CK) and four subsurface drip irrigation treatments at burial depths of 10 cm (D10), 15 cm (D15), 20 cm (D20), and 25 cm (D25) to analyze the effect of the drip irrigation belt burial depth on soil physicochemical properties and soil desalination in the main root zone of saline–alkaline sunflower farmland. Based on macro-genome sequencing technology, the diversity, composition, and structure of soil fungal communities in the main root zone were revealed in response to the depth of drip irrigation. The results show that subsurface drip irrigation treatments improved soil desalination with rates ranging from 15.33% to 26.96%. The D25 treatment achieved an 82.01% higher desalination rate than CK and outperformed D10, D15, and D20 by 43.35%, 13.43%, and 24.89%, respectively, demonstrating the most effective desalination with a 25 cm burial depth under the same water and fertilizer management conditions. Additionally, subsurface drip irrigation enhanced the diversity and abundance of soil fungal communities; the Shannon indices for D15 and D20 were 8.1% and 12.3% higher than that of CK, respectively, whereas the Chao1 indices increased by 21.2% and 17.4%, respectively. During the budding stage, the fungal community in the main root zone (20–40 cm) was dominated by Ascomycetes and Tephritobacterium, with Alternaria being the predominant genus. Notably, the relative abundance of Ascomycetes was 118.8% higher in D25 than in CK. Structural equation modeling quantified the relationships between soil physicochemical properties, with an SMC of 0.94, indicating a model fit within an acceptable range. An SEM analysis revealed that the soil water content (SWC), soil EC, and soil NO₃⁻-N exerted the most significant combined effect on soil fungal composition and diversity. This study examined the effects of the drip irrigation tape burial depth on soil physicochemical characteristics, the fungal community structure, and diversity in the main root zone (20–40 cm) of saline–alkaline sunflower fields under subsurface drip irrigation. This study aims to provide theoretical support for water-saving agricultural practices in saline–alkaline soils. We developed a subsurface drip irrigation method for sunflowers in the lightly to moderately saline–alkaline land in the irrigation area of China’s Tumochuan Plain, and the suitable depth of burial of the drip irrigation belt was 25 cm. Full article

Plant height is a critical biophysical trait indicative of plant growth and developmental conditions and is valuable for biomass estimation and crop yield prediction. This study examined the effects of flight altitude and camera angle in quantifying cotton plant height using unmanned aerial system (UAS) imagery. This study was conducted in a field with a sub-surface irrigation system in Lubbock, Texas, between 2022 and 2023. Images using the DJI Phantom 4 RTKs were collected at two altitudes (40 m and 80 m) and three sensor angles (45°, 60°, and 90°) at different growth stages. The resulting images depicted six scenarios of UAS altitudes and camera angles. The derived plant height was subsequently calculated as the vertical difference between the apical region of the plant and the ground elevation. Linear regression compared UAS-derived heights to manual measurements from 96 plots. Lower altitudes (40 m) outperformed higher altitudes (80 m) across all dates. For the early season (4 July 2023), the 40 m altitude had r² = 0.82–0.86 and RMSE = 2.02–2.16 cm compared to 80 m (r² = 0.66–0.68, RMSE = 7.52–8.76 cm). Oblique angles (45°) yielded higher accuracy than nadir (90°) images, especially in the late season (24 October 2022) results (r² = 0.96, RMSE = 2.95 cm vs. r² = 0.92, RMSE = 3.54 cm). These findings guide optimal UAS parameters for plant height measurement. Full article