Search Results (5,267)

Soil organic carbon (SOC) stocks in cacao agroecosystems are characterized by accumulating large amounts. They depend on the balance between organic matter inputs (plant residues, roots) and losses (decomposition, erosion), being closely related to climatic conditions, soil nature, vegetation type, topography, and land management practices. The objective of this study was to quantify SOC stocks (0–30 cm) and assess key soil fertility indicators across 107 georeferenced sampling locations in cacao production systems of Guamal (Meta, Colombian Llanos Piedmont). Soil pH varies between extremely acidic and moderately acidic (3.8–6.0; mean 4.57), while available P (Bray II) and exchangeable bases showed low concentrations. Organic carbon concentration averaged 1.18% and bulk density averaged 1.17 g cm⁻³. SOC stocks averaged 41.10 Mg C ha⁻¹, ranging from 7.49 to 81.55 Mg C ha⁻¹, evidencing marked spatial contrasts in carbon storage. Spearman correlations highlighted coupled soil chemical controls, including positive associations of pH with Ca²⁺ and P availability and strong negative associations of pH and P with exchangeable Al³⁺, consistent with acidity-driven fertility constraints. Principal component analysis (PCA) further identified a dominant fertility gradient structured by pH, P availability, and Ca²⁺, and a second axis related to organic carbon and cation retention. Spatial modeling using inverse distance weighting (IDW) in ArcGIS supported the visualization of SOC stock variability across the study area. Overall, the results indicate that SOC stocks in these predominantly sandy soils are strongly influenced by acidity-related constraints and heterogeneous nutrient status, underscoring the need for site-specific management to jointly enhance soil fertility and climate-mitigation potential in cacao systems. Therefore, it would be advisable in the future to address the study of differential variations in soil C storage related to chemical fertilizer application rates, especially in the long term. Full article

Riparian vegetation plays an important role in the morphological evolution of rivers; here, an alternative numerical methodology for modeling river morphodynamics influenced by vegetation is presented. The approach integrates a vegetation growth and flow-resistance submodule coupled with the TELEMAC–MASCARET system. Vegetation is represented at the patch scale, and its hydraulic effect is incorporated through an additional drag force in the momentum equation, while stem obstruction is accounted for using the porosity formulation in TELEMAC-2D. Vegetation dynamics consider water depth variability, interspecific competition, and nutrient availability. The model is applied to a braided river reach in southeastern Mexico. The results indicate that riparian vegetation promotes more organized flow paths, enhances bar development, and plays a significant role in modulating bar stability. These findings highlight the importance of explicitly representing flow–sediment–vegetation feedback in river hydro-morphological modeling. Full article

This study demonstrates a hierarchical spectral modelling approach for predicting pasture nutrition metrics using TabPFN (Tabular Prior-Data Fitted Network), a transformer-based machine learning architecture. In the face of climate variability, aligning stocking rates with pasture resources is crucial for sustainable livestock grazing, requiring accurate assessments of both pasture biomass and nutrient composition. Our research, conducted across diverse growth stages at five tropical and subtropical savanna rangeland properties in Queensland, Australia, with native and introduced C4 grasses, employed a hierarchical sampling and modelling strategy that scales from laboratory spectroscopy to Sentinel-2 satellite predictions via uncrewed aerial vehicle (UAV) hyperspectral imaging. Spectral data were collected from leaf (laboratory spectroscopy) through field (point measurements), UAV hyperspectral imaging, and Sentinel-2 satellite imagery. Traditional laboratory wet chemistry methods determined plant leaf and stem nutrient content, from which crude protein (CP = total nitrogen (TN) × 6.25) and dry matter digestibility (DMD = 88.9–0.779 × acid detergent fibre (ADF)) were derived. TabPFN models were trained at each spatial scale, achieving validation R${}^2$ of 0.76 for crude protein at the leaf scale, 0.95 at the UAV scale, and 0.92 at the Sentinel-2 satellite scale. For dry matter digestibility, validation R${}^2$ was 0.88 at the UAV scale and 0.73 at the Sentinel-2 scale. A pasture classification masking approach using a deep neural network with 98.6% accuracy (7 classes) was implemented to focus predictions on productive pasture areas, excluding bare soil and woody vegetation. The Sentinel-2 models were trained on 462 samples from 19 site–date combinations across 11 field sites. The TabPFN architecture provided notable advantages over traditional neural networks: no hyperparameter tuning required, faster training, and superior generalisation from limited training samples. These results demonstrate the potential for accurate and efficient prediction and mapping of pasture quality across large areas (100 s–1000 s km${}^2$) using freely available satellite imagery and open-source machine learning frameworks. Full article

An experiment was conducted in a commercial broiler farm to evaluate birds’ growth performance, intestinal morphology (IM), and total blood carotenoid levels when adding different inclusion rates of microbial muramidase (MUR) to broilers’ feed formula. A total of 336-day-old broilers from Ross 308 were assigned to three groups and were fed from day 1 to day 42. Treatment 1 (T1), the control treatment, was a basal corn soybean meal diet that followed Aviagen nutrient specifications; Treatment 2 (T2) was the control treatment + 350 g MUR per ton of feed; Treatment 3 (T3) was the control treatment + 450 g MUR per ton of feed. Body weight gain (BWG), feed intake (FI), the feed conversion ratio (FCR), carotenoid levels (CLs), and IM from samples of the duodenum, jejunum, and ileum were evaluated on day 42. MUR significantly outperformed the control diet in terms of body weight (BW), resulting in BWs of 2513 g (p = 0.005) and 2463 g with T3 and T2, respectively, versus 2377 g with T1. Daily weight gain (DWG) was 58.77 g and 57.58 g in T3 and T2 (p = 0.0004), respectively, versus 55.54 g in T1. The Daily Feed Intake (DFI) on day 42 was higher in T3 compared to T1 (98.90 g p < 0.0001 versus 97.72 g). The morphology results show higher effects in the duodenum with T3 versus T2 and T1. In addition, the results were significantly higher in the jejunum when using T2 and T3 compared to T1. Goblet cells were not influenced by MUR use in the diets. The broilers’ blood carotenoid levels were significantly higher in T3 (1.75 mg/L p = 0.0026) compared to T1 (1.02 mg/L). These results shed light on broilers’ performance, intestinal health, and nutrient availability when using MUR at different inclusion rates in broiler feed for broilers raised under near-commercial conditions. Full article

Polyunsaturated fatty acids (PUFAs), especially the long-chain omega-3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), are essential nutrients for aquatic organisms and play key roles in growth, reproduction, neural development, and immune function. In freshwater ecosystems and aquaculture systems, the availability of these lipids depends on complex interactions within aquatic food webs, where PUFAs are produced by primary producers and transferred to higher trophic levels. This review summarizes current knowledge on the biosynthesis, regulation, and trophic transfer of PUFAs in freshwater aquaculture food webs, with particular emphasis on interactions among microalgae, zooplankton, and fish larvae. The main biochemical pathways and regulatory mechanisms responsible for PUFA synthesis in microalgae are described, together with the environmental factors that influence their production. The role of zooplankton at an intermediate trophic level is discussed, highlighting their ability to retain, modify, and transfer dietary fatty acids to higher consumers. Finally, the capacity of freshwater fish larvae to synthesize and regulate long-chain PUFAs through key metabolic enzymes is examined, along with the influence of diet and environmental conditions on these processes. By integrating information from molecular, biochemical, physiological, and ecological studies, this review provides an overview of the mechanisms underlying PUFA production and trophic transfer in freshwater aquaculture food webs. Full article

Human cerebral organoids, derived from pluripotent stem cells, are powerful models for studying human brain development. The understanding of how morphogens can be used to guide patterning and differentiation has matured rapidly; however, the influence of basal media components on organoid development remains unclear. Standard organoid media frequently contain non-physiological concentrations of nutrients, including glucose, a central regulator of cellular metabolism and signaling. Here, we examine how glucose availability shapes cerebral organoid growth, morphology, and cell type composition by comparing conventional hyperglycemic media to media with glucose levels more closely resembling normoglycemic conditions. We find that organoids derived from multiple human pluripotent stem cell lines can grow in low glucose, but they exhibit altered growth rates, structural features, and lineage distributions. In H9 embryonic stem cell-derived organoids, inhibition of the mammalian target of rapamycin pathway under low glucose restores neurodevelopmental cell types otherwise diminished in these conditions. These findings highlight glucose as a key determinant of organoid lineage specification and cellular signaling. Importantly, however, glucose modulation does not reduce variability across organoids or cell lines, underscoring the need to better understand and control sources of heterogeneity to improve organoid models. Full article

High-density apple (Malus domestica Borkh.) orchards yield fruits as early as three years after planting but nutrient inputs and availability are paramount to a successful orchard; sustainable practices that balance tree growth and production with environmental concerns are not widely available. In this three-year study, we implemented a split-plot design in three orchards across the Mid-Atlantic region of the USA to evaluate integrated soil management approaches that combine locally sourced carbon-based organic mulch with fertilizers on rhizosphere microbes and tree growth. Bacterial and fungal communities were sampled at the end of the first and third growing seasons in addition to soil and tree-related physicochemical properties. Mulch treatment showed the most significant effect on both the bacterial and fungal groups. Most of these changes reflect the increase in soil organic matter and the increase in carbon cycling. Sequence variants belonging to Flavobacteria and Cytophaga were enriched by the mulch application. A key result from this project is the suppression of the relative abundance of potential soil-borne plant fungal pathogens in all orchards in all years. Additionally, arbuscular mycorrhizal fungi were enriched under the mulch treatment. Microbial shifts accompanying the mulch treatments supported higher trunk cross-sectional areas by the third sampling year that increased by 33.5%. Fertilizer treatments had less pronounced effects on microbial communities. These results highlight the potential for using sustainable, integrated nutrient management strategies to promote healthy orchard soils and support vigorous tree growth while reducing fungal pathogens. Our work will contribute to regional and location-specific fertilizer recommendations for apple producers. Full article

Dietary composition and the intestinal nutrient availability modulate metabolic pathways linked to nutrient sensors, generating molecular adaptations that influence birds’ feeding behavior and performance. The present study investigated the impact of reducing dietary crude protein (CP) and the essential amino acids (AA) lysine (Lys), methionine (Met), threonine (Thr), and tryptophan (Trp) on mRNA expression of the nutrient sensors T1R1 and T1R3, as well as on feeding behavior and productive performance in broiler chickens. A total of 64 one-day-old male Ross 308 broiler chicks were allocated to four dietary treatments: a control diet meeting recommended CP and AA levels (target live weight < 2.0 kg; T1); a diet with 3% reduction in CP and full exogenous AA supplementation (T2); a diet with 3% reduction in CP and 50% AA supplementation (T3); and a diet with 3% reduction in CP without AA supplementation (T4). After a 7-day adaptation, a 32-day single-choice test offered an AA matrix, containing Lys, Met, Thr, and Trp at eight concentrations (0.1–3.5%) for 4 h/day to assess acceptability and palatability. On day 39, six birds per treatment were sampled from the duodenum, jejunum, and ileum for quantitative PCR. Relative to controls, birds fed diets T2, T3, and T4 displayed lower feed consumption, daily gain, feed conversion ratio, and body weight (p < 0.050). These diets downregulated T1R1 and T1R3 mRNA expression (p < 0.001), indicating a molecular adaptation to the nutritional environment, and increased acceptability but reduced palatability (p < 0.050), suggesting altered feeding motivation and sensory perception. Overall, CP and AA reduction impaired performance and modified nutrient-sensor expression and feeding behavior. Full article

Sustainable hydrogen production in water-scarce regions poses critical environmental challenges due to limited freshwater availability and the energy intensity of seawater treatment. This study examines the environmental trade-offs of providing water for hydrogen production via seawater desalination (with or without brine treatment) or freshwater purification, using a comprehensive life cycle assessment (LCA) framework. The assessment centers on three water-stressed countries: the United Arab Emirates (UAE), Spain, and Australia. Results reveal clear trade-offs between freshwater conservation and marine environmental pressures. Brine treatment reduces nutrient-related marine impacts but increases energy-related burdens, particularly under fossil-dominated electricity systems. Water sourcing for electrolysis coupled with energy-intensive desalination systems generally exhibits higher environmental pressures than alternative configurations, whereas freshwater-based supply for hydrogen production pathways shows lower burdens in several impact categories but raise concerns regarding freshwater resource use. Sensitivity analysis confirms that system performance is strongly influenced by water demand and electricity characteristics, highlighting the importance of aligning hydrogen deployment strategies with regional energy and water conditions. Overall, the findings demonstrate that water sourcing decisions play a critical role in shaping the environmental sustainability of hydrogen systems in water-stressed regions and must be evaluated through integrated water–energy planning. Full article

This research evaluated the efficacy of using two types of biochar (non-modified and acidified) from date palm residues (fronds, leaves, pits) as soil amendments for enhancing soil fertility and maize growth. These biochars were produced through slow pyrolysis under oxygen-limited conditions at 500 °C. Our innovative approach was to minimize gas emissions by converting smoke into liquid fertilizer (LS), which was expected to improve seed germination and early plant growth stages. To assess this aim, a completely randomized experiment was conducted under lab conditions, in which 10 maize seeds were placed on double filter papers in Petri dishes and then exposed to seven concentrations of LS (0.0, 0.01, 0.10, 1.0, 10 and 100%, using distilled water for dilution v/v). The LS contains nutrients and bioactive compounds that may enhance seed germination and early plant growth at low concentrations, whereas higher concentrations may cause phytotoxic effects. Results showed that liquefied smoke at 0.1% increased the absolute percentage of maize germination from 75% (control) to 100% and achieved the highest root length of 9.80 cm. Acidified biochars at 5% reduced soil pH from 8.87 to 8.12 and enhanced potassium availability to 87.93 mg kg⁻¹. Conversely, the non-modified biochars contributed to further increases in soil organic matter (up to 1.02%), nitrogen, and phosphorus. In addition, the application of acidified leaf biochar (5%) enhanced maize shoot growth by 133%, chlorophyll content by 39%, and potassium uptake by 110%. This research establishes a scalable approach for converting agricultural waste into climate-resilient resources, effectively addressing soil degradation in arid environments, boosting crop resilience, and furthering the objectives of a circular bioeconomy. Full article

Effective management of wastewater discharges requires understanding the spatial distribution of pollutants both within engineered infrastructure and in receiving environments. However, spatial data sparsity constrains comprehensive assessment. This critical review examines the role of Geographic Information Systems (GIS) and statistical interpolation techniques in bridging these data gaps for wastewater-derived pollutants. Moving beyond a simple compilation of methods, this paper provides a synthesizing framework that categorizes and evaluates interpolation techniques-from deterministic and geostatistical approaches to emerging machine learning (ML) and hybrid models- based on their ability to address specific challenges in wastewater systems. A key contribution is a systematic review and meta-analysis following PRISMA guidelines, synthesizing evidence from 22 studies that directly compare interpolation methods for wastewater-relevant parameters (BOD₅, COD, nutrients, heavy metals) in both engineered systems and impacted water bodies. Results indicate that machine learning methods significantly outperform traditional approaches, with a pooled 21% reduction in RMSE compared to Ordinary Kriging (95% CI: 15–27%). However, subgroup analyses reveal context dependency: ML advantages are most pronounced for organic pollutants (29% reduction) and data-rich environments (27% reduction with n > 100), while geostatistical methods remain competitive for physical parameters (8% reduction, non-significant) and data-sparse scenarios (12% reduction with n < 50). Co-Kriging achieves 15% RMSE reduction over Ordinary Kriging when auxiliary variables are available. The review explores applications in pollutant tracking, infrastructure planning, and environmental impact assessment, highlighting how integration of real-time sensor data (IoT) and remote sensing is transforming static maps into dynamic monitoring tools. Finally, a forward-looking research roadmap is presented, emphasizing hybrid modeling frameworks, digital twin integration, and improved uncertainty communication for decision support. By quantitatively synthesizing the current state-of-the-art and identifying critical knowledge gaps, this review aims to guide future research towards more intelligent, adaptive, and reliable spatial assessments of wastewater-derived pollutants. Full article

This review investigates the multifaceted roles of nitrogen-fixing and phosphate-mobilizing bacteria in natural ecosystems, with a particular focus on their contributions to plant growth and sustainable soil management. These microbial communities contribute substantially to nutrient cycling by converting atmospheric nitrogen into plant-available forms and mobilizing insoluble phosphorus in soil, thereby enhancing soil fertility and promoting sustainable plant productivity. This review synthesizes current knowledge on the mechanisms underlying biological nitrogen fixation, phosphate solubilization and mineralization, and the production of plant growth–promoting metabolites. Particular attention is given to plant–microbe interactions and their role in improving nutrient availability, regulating plant physiological processes, and enhancing tolerance to abiotic stresses such as salinity, drought, and heavy metal contamination. The findings underscore the ecological importance of these plant-associated microbial communities and highlight their potential applications in biofertilizer and biostimulant development for sustainable agriculture and reduced dependence on synthetic fertilizers. Full article

Sustainable aquaculture growth necessitates innovative strategies to meet the global protein demand while minimizing environmental impacts. This narrative review synthesizes the current understanding and emerging approaches for optimizing nutrient cycling and trophic transfer efficiency in pond-based aquaculture systems. We highlight two primary strategies: ‘demand-oriented feeding’, which adaptively balances feed inputs with natural food availability, and the ‘nutritious pond concept’, which enhances pond ecology through carbon/nitrogen ratio management and waste-driven nutrient recycling. A critical examination of the scalability and environmental trade-offs associated with these strategies is also presented. Despite the challenges presented by these strategies, their combination could create a more dynamic, ecosystem-based approach to aquaculture that is more resource-efficient and environmentally friendly, contributing to the development of ponds as sustainable, productive ecosystems that enhance efficiency, reduce waste, and support economic viability. Finally, we explored polyculture as an ecological strategy, highlighting its synergistic mechanisms for maximizing food web efficiency and its potential to enhance the two primary strategies. Full article

The coupling of water and nitrogen (N) availability critically constrains alpine plant growth and ecosystem productivity, yet the mechanistic links between plant functional traits and resource use efficiencies (rain use efficiency, RUE; nitrogen use efficiency, NUE) along precipitation gradients remain unclear. This study aimed to test whether coordinated shifts in plant functional traits are associated with spatial variation in RUE and NUE across a precipitation gradient on the Changtang Plateau. Here, combining transect surveys with N-addition experiments on the Changtang Plateau, we measured biomass and leaf/root functional traits on four typical grasslands and analyzed the spatial variations in RUE, NUE, and fertilizer use efficiency (FUE). Our results demonstrated contrasting spatial patterns: with increasing precipitation, soil resource availability, community species richness, and biomass significantly improved, and vegetation shifted from a water-conservative strategy in arid regions to a nutrient-efficient strategy in humid regions. FUE increased with precipitation (p < 0.05), with low-dose nitrogen addition exerting more pronounced effects in humid regions, indicating greater responsiveness to fertilization. This transition in resource use patterns is underpinned by a coordinated divergence in functional traits: as water limitation eases, communities exhibited decreasing specific root length (high specific root length, SRL) coupled with increasing specific leaf area (high specific leaf area, SLA) along the gradient. Our findings demonstrate that functional trait variation is associated with the optimization of resource acquisition across environmental gradients. These results provide a mechanistic basis for adaptive management in climate-sensitive alpine biomes, where differentiated grassland management schemes may enhance ecosystem productivity—water conservation and reduced disturbance in arid regions, with moderate low-dose nitrogen fertilization and species diversity protection in humid regions. Long-term ecosystem responses to such management approaches require further investigation. Full article

Circadian rhythms are predictable biological patterns that recur about every 24 h and, in mammals such as humans, are entrained to daylight by the hypothalamic suprachiasmatic nucleus (SCN). Although light is a potent zeitgeber for the SCN, cells outside of the SCN can synchronize to daily nutrient and metabolic cues. In these tissues, nutrient metabolic processes are regulated by the molecular clock in anticipation of food availability or scarcity. Furthermore, nutrients and metabolic processes themselves may act upon members of the molecular clock to regulate their expression and activity. These interactions maintain synchrony between the SCN and food-entrainable clocks when activity and nutrient intake align. However, the light-entrainable SCN and food-entrainable clocks can become desynchronized, particularly in modern society where humans are commonly exposed to shift work and jet lag. Therefore, the mechanisms for sensing nutrients at specific times of day are critical components of circadian timekeeping and organismal homeostasis. In the following narrative review, we aim to synthesize current evidence on time-of-day-dependent nutrient sensing in mammalian systems, examine how nutrient-derived signals and metabolic processes interact with molecular clock mechanisms across cellular and tissue levels, and evaluate the integration of central and peripheral clocks in regulating gene expression, energy utilization, and organismal homeostasis, including the impacts of feeding cycles and circadian disruption. While previous reviews have discussed circadian nutrient metabolism, this review provides conceptual support for the role of nutrients as time-of-day signaling mechanisms. Full article