Search Results (2,713)

The rhizosphere, the zone around the roots of plants, including the root, the soil on the root itself, and the surrounding area soil, is the hotspot for the production of reactive oxygen species (ROS). Functioning as redox signaling mediators, rhizosphere ROS regulate a series of key processes in the rhizosphere microenvironment. These biological and geochemical events cover root morphogenesis, the formation of beneficial plant–microbe symbioses, and element biogeochemical transformations. Nevertheless, the pronounced spatial heterogeneity, drastic redox fluctuations, and intricate interfacial interactions within the rhizosphere impede accurate in situ detection of ROS. Beyond technical barriers, the coupled regulatory effects exerted by biotic and abiotic factors on ROS dynamics, together with the associated ecological outcomes induced by rhizosphere ROS, remain difficult to fully disentangle. This review first discusses updated strategies and optimized methodologies for in situ rhizosphere ROS monitoring. We then characterize the spatial distribution patterns and microscale hotspots of rhizosphere ROS. Importantly, this review dissects the complex coupled regulatory network formed by biotic, abiotic, and environmental factors and molecular regulatory pathways that control ROS production. Furthermore, this study systematically illustrates diverse environmental effects triggered by rhizosphere ROS. Finally, the present work identifies prevailing research gaps and unresolved limitations in current studies. On this basis, we further propose targeted research directions for future studies in this field, providing comprehensive theoretical evidence to deepen the understanding of rhizosphere ROS formation and their mediated biogeochemical processes. Full article

The mixed application of plant residues to treat petroleum-contaminated soil may increase remediation efficiency by leveraging their mixed decomposition effects. However, it remains unclear whether this approach may also lead to opposite effects. In this study, plant residues of 7 common plant species, namely, Bothriochloa ischaemum (Bi), Lespedeza davurica (Ld), Artemisia gmelinii (Ag), Heteropappus altaicus (Ha), Artemisia annua (Aa), Sophora davidii (Sd), and Agropyron cristatum (Ac), from the petroleum-producing area of northern Shaanxi and their 9 mixtures were used to treat petroleum-contaminated soil with a crude oil content of 15.00 g kg⁻¹. The samples were incubated at 25 °C under constant humidity for 120 days to determine the potential effects of mixed plant residues on stimulating contaminant degradation and restoring soil biological and chemical properties. The results revealed that (1) among all mixed plant residue treatments, combinations of BiLdAg, LdSd and HaAa significantly weakened the overall contaminant degradation efficiency. In particular, the LdSd and HaAa mixtures simultaneously strongly inhibited the degradation of saturated hydrocarbons and aromatic hydrocarbons; compared with the expected theoretical values, their degradation rates decreased by 12.36–35.25% and 9.91–19.82%, respectively (p < 0.05). (2) Mixtures including LdAgHa, BiLdAg, LdSd, LdAgHaAa, LdHa and HaAgAcSd significantly impaired the capacity of plant residues to replenish soil available nutrients and activate soil enzyme activities. The LdAgHa mixture exhibited the strongest antagonistic effect: its improvement efficiency in terms of soil nitrate nitrogen content and sucrase, dehydrogenase and polyphenol oxidase activities (the increase relative to that in contaminated soil) decreased by 30.60–76.89% relative to the theoretical expectations (p < 0.05). Overall, the effects of mixed plant residue addition on contaminant degradation and the restoration of damaged soil biochemical properties were negatively correlated. (3) Increased chemical specialization of mixed residues and higher mass proportions of Ld and Bi residues in mixtures tended to aggravate the above antagonistic inhibitory effects. When all the remediation indicators were comprehensively evaluated, the mixed application of plant residues failed to universally improve the remediation performance of crude oil-contaminated soil. Under experimental conditions, BiLdAg and LdSd residue combinations may lead to remarkable antagonistic interactions and lower the efficiency of necrophytoremediation, which should be avoided in practical field applications of this remediation technology. Full article

Plant diversity is often expected to enhance soil organic carbon (SOC) storage through greater and more heterogeneous plant inputs, but its relationships with functionally distinct SOC fractions in natural forests remain uncertain. This study compiled published SOC fraction data from 341 surface soil observations in natural forests across China and spatially matched these records with gridded plant alpha diversity, forest age, climate, topographic and soil properties datasets to evaluate biotic and abiotic associations with SOC, particulate organic carbon (POC), mineral-associated organic carbon (MAOC) and MAOC/SOC. Linear regression, multiple regression, piecewise structural equation modelling and stratified analyses were used to evaluate whether plant diversity was associated with the absolute accumulation and relative stabilization of SOC fractions. Plant alpha diversity was negatively associated with ln[SOC], ln[POC] and ln[MAOC] at the national scale, whereas its bivariate relationship with MAOC/SOC was weak. After accounting for forest age and environmental covariates, plant alpha diversity remained negatively related to the absolute contents of SOC fractions while showing a positive association with MAOC/SOC. Forest age was positively associated with ln[SOC], ln[POC] and ln[MAOC], and POC was more strongly related to plant diversity and forest age than MAOC. In contrast, MAOC and MAOC/SOC were more strongly associated with mineral protection potential, soil pH and precipitation background. Structural equation models indicated that mineral protection potential and mean annual precipitation were associated with greater MAOC accumulation and SOC allocation to the mineral-associated fraction, whereas temperature and topography were linked to MAOC partly through indirect associations with soil physicochemical conditions. Stratified analyses showed that plant diversity associations varied among forest types and climatic backgrounds. Additional interaction models showed that mineral protection potential significantly moderated the associations between plant alpha diversity and ln[SOC], ln[POC] and ln[MAOC], with negative diversity associations weakening under higher mineral protection potential. These findings indicate that plant diversity associations with SOC fractions in natural forests cannot be interpreted as universally positive input relationships. Instead, their direction and strength depend on hydroclimatic context and soil mineral protection, especially for the absolute accumulation of SOC fractions. Full article

Nanobubble-saturated water (NBSW) has gained prominence in agricultural research due to its ability to affect root-zone oxygenation and soil–plant interactions. This review aimed to analyze the available research on the impacts of NBSW on soil moisture storage, percolation, electrical conductivity (EC), microbial activity, and soil structural dynamics across different gas types and soil textures. Therefore, a systematic literature search was carried out, and the retrieved publications were synthesized with keyword co-occurrence and bibliometric analysis. This review fills the gap in the literature by integrating findings on root-zone oxygenation, nutrient dynamics, and soil structural responses into a single framework. Research showed that NBSW may influence water partitioning by increasing evaporation and lowering percolation, leading to different vertical moisture gradients. However, the effects could be impacted by the soil texture, as finer textures retained more moisture, while coarser soils increased oxygen penetration and microbial stimulation. Furthermore, increased oxygen availability under NBSW further changed microbial community activity, which could impact soil CO₂ emissions and nitrogen and phosphorus cycling. While repeated NBSW application may gradually increase soil compaction, particularly in finer-textured soils, overall, NBSW demonstrated versatile watering modifications that might influence soil physical, chemical, and biological processes. However, further research is needed to determine the appropriate gas types and application strategies for different soils under real field-scale agricultural conditions. Full article

Biochar has emerged as one of the most promising nature-based strategies for improving soil quality, enhancing crop productivity and supporting climate-smart agriculture. However, the agronomic performance of biochar remains highly variable because its effects are governed by complex interactions among feedstock characteristics, pyrolysis conditions, soil properties and management practices. This review synthesizes recent advances in biochar research (2019–2026), examining how production variables determine biochar physicochemical properties and how these properties subsequently influence soil functioning, plant performance and long-term agricultural sustainability. The review integrates evidence on feedstock selection, pyrolysis technologies, biochar modification strategies and the relationships between biochar properties and soil physical, chemical and biological processes. Particular attention is given to crop productivity, nutrient use efficiency, stress mitigation, contaminant immobilization, greenhouse gas mitigation and long-term soil resilience. Across the literature, the most consistent agronomic benefits were observed when biochar was applied to degraded or resource-limited soils and integrated with complementary management practices, whereas responses were often limited under fertile soils, low application rates or short experimental periods. Rather than identifying a universally superior biochar, the evidence indicates that agronomic performance depends on matching biochar characteristics to specific production objectives and environmental conditions. Based on these findings, this review proposes a transition from generalized biochar application towards optimized deployment strategies supported by standardized characterization, long-term multi-site validation and integrated environmental and economic assessments. This synthesis provides a comprehensive framework for guiding future research and facilitating the effective implementation of biochar within sustainable and regenerative agricultural systems. Full article

Iron (Fe) and selenium (Se) deficiencies are global health concerns associated with adverse health outcomes. Plants constitute a dietary source of these elements, particularly for individuals following plant-based diets. However, plant Fe availability is limited by soil processes that reduce Fe mobility and uptake, whereas Se accumulation is constrained by the low abundance of Se in soils. Increasing Fe and Se concentrations in edible plant parts through biofortification represents a sustainable strategy to alleviate micronutrient deficiency. This review examines the mechanisms governing Fe and Se uptake, translocation, metabolism, and genetic regulation, and discusses current biofortification strategies, including agronomic practices, natural and microbial-based approaches, conventional breeding and marker-assisted selection, transgenic technologies, and nanoparticles. While cereals remain the principal targets of large-scale biofortification programs, recent advances in horticultural crops are also highlighted because of their growing nutritional and commercial importance. Current evidence indicates that integrated agronomic and genetic approaches are more effective than single interventions, although simultaneous Fe and Se biofortification remains largely underexplored. Successful biofortification is also strongly influenced by soil properties, nutrient interactions, and crop genotype. Emerging tools, including plant–microbe interactions and synthetic biology, offer promising opportunities to enhance micronutrient accumulation and bioavailability. Further research should optimize integrated Fe–Se biofortification strategies while addressing agronomic and socioeconomic constraints to support their large-scale adoption and contribute to sustainable food systems. Full article

Improving the nutritional quality of food through advanced and sustainable agricultural practices has become a key objective of modern vegetable crop production. Emphasis is placed on increasing the content of health-promoting bioactive compounds, such as vitamins and polyphenols, particularly flavonoids whose accumulation is strongly affected by various biotic and abiotic stress factors. To mitigate stress-induced limitations and enhance plant performance, biostimulants are increasingly applied. Among them, Trichoderma spp. are widely recognized for their ability to promote plant growth and resilience, primarily through enzymatic activity and the production of bioactive metabolites. The aim of this study was to evaluate the potential of the native Trichoderma sp. strain STP8 to enhance the production of bioactive compounds through seed and soil applications at planting and 26 days after planting (DAP), applied individually or in combination. A spore suspension (4 × 10⁶ spores mL⁻¹) was used. The experiment was arranged in a randomized complete block design with five replicates. At harvest (43 DAP), dry matter, ascorbic acid, chlorophyll, and carotenoid contents were determined. Additionally, flavonoids and non-flavonoids, total phenolics, individual phenolic compounds, and antioxidant capacity were analyzed. Achieved results demonstrate that the effects of the native Trichoderma sp. strain STP8 on lettuce secondary metabolism and antioxidant properties are strongly dependent on the developmental stage at which inoculation is performed, providing further insight into the stage-specific interactions between plans and Trichoderma. Practically, a single application at planting proved to be the most effective strategy for enhancing the accumulation of bioactive compounds, indicating that optimized application timing may improve the efficacy of Trichoderma-based biostimulants, while avoiding unnecessary repeated applications. These findings support the potential use of native Trichoderma strains as sustainable tools for improving the nutritional and functional quality of lettuce. Further research integrating physiological, biochemical, and molecular analyses is required to elucidate the mechanisms by which the native Trichoderma sp. strain STP8 regulates the biosynthesis of bioactive compounds in lettuce. Full article

Urban rocky desertification areas are characterized by shallow soils, rock–soil mosaics, and strong human disturbance, so infiltration processes may differ from those in homogeneous soils. However, interactions among multiple controlling factors remain insufficiently quantified. This study compared soil infiltration under artificially restored vegetation (planted grassland (PG) and planted woodland (PW)), and natural secondary vegetation (secondary grassland (SG) and secondary woodland (SW)). Saturated hydraulic conductivity (Ks) and falling-head duration (T) were measured using falling-head tests on undisturbed soil columns. Soil physical properties were then integrated with partial least squares structural equation modeling (PLS-SEM) to assess the effects of rocky desertification, soil aggregates, and porosity. Soil bulk density was significantly lower under artificially restored vegetation, whereas capillary porosity, non-capillary porosity, and water-holding capacity were significantly higher (p < 0.05). Infiltration performance followed PW > PG > SW > SG. PLS-SEM indicated that rocky desertification (−0.78), porosity (0.51), and aggregates (−0.03) jointly regulated infiltration, with non-capillary porosity as the dominant positive factor. Higher infiltration in artificially restored plots was mainly associated with improved pore structure. These findings support vegetation configuration and soil–water management in urban rocky desertification areas. Full article

Legume–rhizobium symbiosis is fundamental to sustainable agriculture because it supplies biologically fixed nitrogen, improves soil fertility, and reduces reliance on synthetic fertilizers. However, abiotic and chemical stresses, including drought, salinity, flooding, temperature extremes, heavy metals, and organic pollutants, disrupt nodulation and biological nitrogen fixation, limiting crop productivity and ecosystem sustainability. This review synthesizes current knowledge of the regulatory networks that enable legume–rhizobium symbiosis to adapt to environmental stress. We discuss how stress influences symbiotic signaling, infection, oxygen homeostasis, nitrogenase protection, phytohormonal regulation, antioxidant defenses, exopolysaccharide production, and plasmid-mediated adaptation. We further highlight the roles of root nodule-associated microorganisms and microbial interactions in maintaining symbiotic stability under adverse conditions. Finally, recent advances in multi-omics, genome editing, synthetic biology, and microbial consortia are evaluated for their potential to improve stress-resilient bioinoculants. Collectively, this review emphasizes that resilience of the legume–rhizobium symbiosis is an integrated property of both plant and microbes and identifies key regulatory mechanisms that can be exploited to develop climate-resilient and sustainable agricultural systems. Full article

Litter and understory are key components of forest ecosystems, playing vital roles in soil carbon inputs and microhabitat regulation. Their removal is a common forest management practice: litter removal (L) reduces fire and pest risks while promoting nutrient cycling, whereas understory removal (U) alleviates nutrient competition between understory plants and trees. However, the combined effects and underlying mechanisms of litter removal (L) and understory removal (U) on soil nematode communities remain unclear. This study investigated the individual and interactive effects of L and U on soil nematode communities in a coniferous–broadleaved mixed forest in a subtropical–warm temperate transition zone. The results showed that L significantly reduced soil nematode abundance by 18.1%, increased the relative abundance of bacterivores and omnivores-predators by 21.1% and 103.3%, respectively. U significantly elevated the relative abundance of fungivores by 30.8%, while both L and U reduced the relative abundance of plant-parasitic nematodes. Significant interactive effects between L and U were observed on soil nematode abundance, relative abundances of fungivores, plant-parasites, maturity index, and plant parasite index. Litter plus understory removal (LU) alleviated soil nematode resource limitation through synergistic regulation of resource pulses and microhabitat modification. Faunal analysis based on structure and enrichment indices indicated that LU enhanced food web structural complexity and resource-use efficiency. Redundancy analysis identified microbial biomass carbon, microbial biomass nitrogen, and soil total carbon as key drivers of nematode community differentiation. This study reveals the synergistic regulatory patterns of litter and understory vegetation on soil nematode communities, providing a theoretical reference for understanding the responses of soil nematodes to understory disturbance during the growing season in climate transitional forests, and offering basic data for long-term monitoring and forest soil management. Full article

Mediterranean olive agroecosystems are increasingly recognized as potential contributors to climate change mitigation, mainly through the sequestration and storage of soil organic carbon (SOC). However, the mitigation potential of such an agroecosystem cannot be inferred solely from changes in SOC stock. This reflects the interconnected nature of perennial tree cropping systems, where biomass growth, soil carbon stabilization, management-induced greenhouse gas emissions and accounting assumptions interact to determine mitigation outcomes. This review synthesizes current knowledge on carbon dynamics in olive agroecosystems from a system-level perspective. We show that SOC is the most persistent carbon pool, and its accumulation is governed by organic inputs, stabilization processes, disturbances, and site-specific constraints. Management practices can increase carbon inputs or reduce losses, but also create trade-offs through erosion, decomposition, and non-CO₂ emissions. Existing assessments are limited by methodological inconsistencies, system boundaries, life-cycle assumptions, and MRV requirements. Olive agroecosystems should be assessed as connected soil–plant–atmosphere systems rather than isolated SOC reservoirs. We conclude that climate change mitigation in woody agroecosystems should be assessed through integrated carbon balance frameworks combining SOC dynamics, biomass turnover, greenhouse gas fluxes, and management pathways within transparent system boundaries. This synthesis highlights the value of Mediterranean olive agroecosystems as representative perennial systems for evaluating climate change mitigation processes. Full article

Intensified paddy production plays a crucial role in sustaining rice productivity and food security; however, long-term high-frequency puddling, heavy machinery operations under wet soil conditions, simplified cropping systems, and insufficient organic matter inputs have progressively degraded the physical structure of paddy soils. Such structural degradation not only weakens soil water movement, nutrient supply, and aeration but also restricts rice root penetration, alters rhizosphere processes, and disrupts plant–soil feedbacks. Previous studies have largely focused on individual aspects such as soil compaction, amendment-based improvement, water management, or root responses, whereas an integrated understanding of the multi-source drivers, functional consequences, and restoration pathways of soil structural degradation in intensified paddy fields remains limited. Following the overarching theme of soil degradation and regeneration, this review systematically synthesizes the indicator framework, formation mechanisms, degradation typology, ecological consequences, and regulation strategies of paddy soil structural degradation. We further clarify the transition of degraded paddy soils from single physical constraints to the coupled decline of physical, chemical, and biological functions, and compare the agronomic performance, environmental implications, implementation feasibility, and trade-offs of different restoration pathways. Existing evidence indicates that soil structural degradation in paddy fields can impair root-zone pore connectivity, rhizosphere oxygen supply, nutrient acquisition, microbial-mediated carbon and nitrogen cycling, and greenhouse gas regulation, thereby affecting rice growth, yield stability, and the ecological sustainability of paddy systems. Accordingly, the restoration of degraded paddy soils should move beyond short-term loosening or single-factor amendment toward integrated regeneration strategies that maintain soil structural health, reconstruct plough-layer functions, enhance root–soil interactions, and promote the synergistic recovery of pore networks, aggregates, organic carbon, and microbial processes. This review provides a theoretical basis and research reference for the precise restoration of soil structural constraints and the sustainable management of plant–soil systems in intensified paddy fields. Full article

Grafting and foliar calcium application are common practices for improving vegetable crops, but their interactions in soil and soilless cultivation systems are not well understood. To address these knowledge gaps for sustainable greenhouse cucumber production, this study investigated the effects of calcium foliar application (control, 200 mg/L as nano-CaCO₃ or CaCl₂) and grafting (no grafting, grafting on Ganate rootstock or Routpower rootstock) on the growth and yield of greenhouse cucumber cv. Saba in soil and soilless systems. It should be noted that the two cultivation systems differed in several management factors (pot size, substrate, irrigation frequency, and fertilization method), and this study compares complete production packages rather than isolating individual factors. The experiment was conducted in a greenhouse using a factorial design with four replications. The results showed that the cultivation system was the dominant factor. Soilless cultivation significantly increased shoot fresh weight (307–344 g), plant height (265–326 cm), number of fruits (36–54 per plant), and fruit yield (2.7–4.5 kg per plant) compared to soil cultivation (shoot fresh weight: 177–216 g; yield: 0.4–1.0 kg per plant). Conversely, plants grown in soil had higher leaf dry weight percentage, root dry weight percentage, chlorophyll, and carotenoids. The effects of grafting were system dependent, with non-grafted plants performing as well or better in soilless culture, while grafted plants (especially Saba/Routpower combination) showed some soil-based advantages, including greater root length. Foliar calcium did not significantly improve most parameters, indicating that standard nutrient management provided sufficient calcium or that the 200 mg/L concentration was insufficient. Under the conditions tested, ungrafted plants grown without foliar calcium supplementation in soilless culture achieved yields comparable to more complex treatments, suggesting a simpler and more cost-effective production strategy. Full article

Heavy metals are persistent environmental contaminants that accumulate in soils and vegetation, posing significant risks to ecological systems and human health. Pinus nigra needles are widely recognized as effective biomonitors for reflecting spatial and temporal variations in atmospheric heavy metal deposition. However, the complex, nonlinear interactions among multiple pollutants, environmental factors, and site-specific conditions limit the effectiveness of conventional statistical approaches in accurately modeling and predicting contamination patterns. This study investigated the spatial and seasonal distribution of heavy metals in soils and Pinus nigra needles across different environmental settings in Adıyaman, Türkiye, including urban traffic zones, an organized industrial area, a cement factory vicinity, and a clean reference site. Metal concentrations were determined using inductively coupled plasma mass spectrometry (ICP–MS) following standardized acid digestion procedures. To address the limitations of traditional methods and capture complex nonlinear relationships, advanced machine learning (ML) algorithms—multilayer perceptron, Random Forest, XGBoost, LightGBM, CatBoost, and Gradient Boosting—were employed to model elevation based on heavy metal concentrations. The dataset was divided into training (80%) and testing (20%) subsets, and model performance was evaluated using R², RMSE, MAE, MAPE, and EVS. Among the models, XGBoost exhibited superior predictive performance. Excluding Cd, Cr, and Cu, it achieved R² = 0.9996 (RMSE = 0.068) in training and R² = 0.9526 (RMSE = 17.77) in testing. Including these metals further improved performance to R² = 0.9999 (RMSE = 0.054) for training and R² = 0.9890 (RMSE = 5.55) for testing. The results confirm that Pinus nigra needles are reliable bioindicators of heavy metal accumulation. More importantly, the integration of biomonitoring data with ML techniques provides a powerful framework for capturing complex environmental interactions and improving predictive accuracy, thereby supporting more effective environmental monitoring, risk assessment, and sustainable management strategies. Full article

Bacteria play a vital role in enhancing host resistance to salt–alkali stress. However, the composition and structure of bacterial communities associated with halophytes under natural high salt–alkali conditions remain poorly understood. Here, a transect comprising six sampling points (0, 9, 18, 27, 36, and 45 m) was established across a natural population of Salicornia europaea L. in Guhya Salt Lake salt–alkali soils. At each sampling site, bulk soil, rhizosphere soil, root, and leaf samples were collected for 16S rRNA gene amplicon sequencing. The pH and soil electrical conductivity (EC) significantly increased along the sampling sites establishing a distinct salt–alkali gradient. This gradient provides an ideal model for studying the ecological adaptation mechanisms of halophytes and their related microorganisms. The results showed that alpha diversity (Shannon index) of bacterial communities significantly decreased across sampling sites in bulk soil, rhizosphere soil and root, but not in leaf. Beta diversity varied significantly across sampling points in all sample types examined. Linear Discriminant Analysis Effect Size (LEfSe) identified specific microbial biomarkers (such as Halomonas spp.) for each sampling point and sample type, many of which are known salt–alkali-tolerant lineages. Random forest and correlation analysis indicated that soil chemical properties had a clear impact on these identified biomarkers. Overall, salt–alkali gradient was associated with habitat-specific microbial communities across plant compartments and certain bacterial taxa were found to be enriched in specific niches. These taxa include known salt–alkali-tolerant lineages, and may putatively contribute to host adaptation to extreme environments, which provides deeper insights into plant–microbe interactions in natural ecosystems and offers potential microbial resources for improving crop salt–alkali tolerance. Full article