Search Results (205)

Rhizosphere hypoxia, caused by soil compaction and waterlogging, is a major constraint on agricultural productivity. It severely impairs crop growth and yield by inhibiting root aerobic respiration, disrupting energy metabolism, and altering the rhizosphere microecology. Micro-nano bubbles (MNBs) show significant potential for alleviating rhizosphere hypoxia due to their unique physicochemical properties, including large specific surface area, high oxygen dissolution efficiency, prolonged retention time, and negative surface charge. This paper systematically reviews the key characteristics of MNBs, particularly their enhanced mass transfer capacity and system stability, and outlines mainstream preparation methods such as cavitation, electrolysis, and membrane dispersion. And the multiple alleviation mechanisms of MNBs—including continuous oxygen release, improvement of soil pore structure, and regulation of rhizosphere microbial communities—are clarified. The combination of MNBs aeration and subsurface drip irrigation can increase soil aeration by 5%. When applied in soilless cultivation and conventional irrigation systems, MNBs enhance crop yield and nutrient use efficiency. For example, tomato yield can be increased by 12–44%. Furthermore, the integration of MNBs with water–fertilizer integration technology enables the synchronized supply of oxygen and nutrients, thereby optimizing the rhizosphere environment efficiently. This paper sorts out the empirical effects of MNBs in soilless cultivation and conventional irrigation, and provides directions for solving problems such as “insufficient oxygen supply to deep roots” and “reactive oxygen species (ROS) stress in sensitive crops”. Despite these significant advantages, the industrialization of MNBs still needs to overcome challenges including high equipment costs and insufficient precision in parameter control, so as to promote large-scale agricultural application and provide an innovative strategy for the management of rhizosphere hypoxia. Full article

De-sealing, or depaving, is increasingly adopted to restore soil permeability and support green infrastructure, yet its potential to recover soil functions remains insufficiently understood. This study reports one year of soil monitoring following the de-sealing of a brownfield site in Milan (Italy). It compares the evolution of pedoclimatic parameters in sealed and de-sealed soils and assesses the suitability of recycled aggregates (RAs) from demolition waste as a soil-forming material. Buried sensors continuously recorded pedoclimatic parameters, temperature, water content, and oxygen concentration, while periodic sampling was carried out to analyse soil chemical properties, bacterial community composition, and the quality of percolation water (heavy metal content). De-sealing immediately improved pedoclimatic conditions, enhancing soil aeration, water regulation, and heat exchange capacity. No significant variation was detected in soil chemical properties, apart from pH fluctuations linked to the leaching of alkaline ions from concrete-based RAs. The presence of RAs caused no adverse effects on either soil or percolation water. Bacterial community composition was strongly associated with soil organic carbon, C:N ratio, and soil water content, without showing clear temporal trends. Overall, the study demonstrates that de-sealing rapidly triggers soil functional recovery and that, when properly characterised for composition and contamination risk, RAs pose no evident threat to the surrounding environment. Full article

The cultivation of Salvia miltiorrhiza in arid regions is challenged by limited water availability and suboptimal soil aeration, which constrain nitrogen uptake and the accumulation of secondary metabolites. This study evaluated the integrated effects of magnetized and aerated irrigation on mitigating these constraints. Results indicated that the combined magnetized and aerated irrigation treatment demonstrated remarkable efficacy, achieving a 25.2% increase in soil nitrate nitrogen availability and 36.1% enhancement in root dry matter weight. Crucially, this optimized rhizosphere environment preferentially boosted the biosynthesis of salvianolic acid B and key tanshinones (T. IIA, Cryptotanshinone, T. I), with content increases exceeding 22% compared to conventional irrigation, representing substantial improvements in the herb’s therapeutic value. Water terminal magnetization proved superior to water source positioning, while aerated irrigation enhanced soil nitrification more effectively than magnetization alone. By concurrently improving rhizosphere oxygenation and creating favorable conditions for nutrient uptake, this strategy offers a sustainable approach for improving the quality and biomass of Salvia miltiorrhiza in water-limited environments. Full article

Straw return is essential for improving soil fertility, recycling organic matter, and sustaining productivity in rice–wheat systems. This study focuses on the conceptual design and systematic analysis of the spatial and temporal variability of straw return methods and their classification. We proposed and analyzed 36 technical models for straw return by integrating spatial distribution (depth and horizontal placement) with temporal variability (decomposition period managed through mulching or decomposers). The models of straw return were categorized into five classes: mixed burial, even spreading, strip mulching, deep burial, and ditch burial. Field experiments were conducted in Babaiqiao Town, Nanjing, China, using clay loam soils typical of intensive rice–wheat rotation. Soil properties (bulk density, porosity, and moisture content) and straw characteristics (length and density) were evaluated to determine their influence on decomposition efficiency and nutrient release. Results showed that shallow incorporation (0–5 cm) accelerated straw breakdown and microbial activity, while deeper incorporation (15–20 cm) enhanced long-term organic matter accumulation. Temporal control using mulching films and decomposer agents further improved moisture retention, aeration, and nutrient availability. For the rice–wheat system study area, four typical straw return modes were selected based on spatial distribution and soil physical parameters: straw even spreading, rotary plowing, conventional tillage with mulching, and straw plowing with burying. This study added to the growing body of literature on straw return by providing a systematic analysis of the parameters influencing straw decomposition and the incorporation. The results have significant implications for sustainable agricultural practices, offering practical recommendations for optimizing straw return strategies to improve soil health. Full article

Soil stabilization is a key process in geotechnical engineering, particularly for expansive clay soils that exhibit low strength and high volume-change potential. This study examines the use of waste tire powder (WTP) and autoclaved aerated concrete powder (ACP) as sustainable soil additives to improve mechanical performance while promoting sustainable waste recycling. Clayey soils from the Çorlu/Tekirdağ region were blended with varying proportions of WTP and ACP, and their properties were evaluated through Standard Proctor compaction, unconfined compressive strength (UCS), and California bearing ratio (CBR) tests. The results showed that UCS increased from 3.7 MPa to 4.5 MPa with 5% ACP, while CBR values rose from 21.3% to 29.8% with 17% ACP addition. Incorporating 2% WTP enhanced elasticity and reduced brittleness, although higher WTP contents (4%) lowered cohesion and strength. The optimum formulation, 2% WTP + 5% ACP, produced balanced improvements in strength, stiffness, and deformation resistance. The novelty of this research lies in establishing a hybrid stabilization mechanism that combines the elastic contribution of WTP with the pozzolanic bonding of ACP. Beyond technical improvements, recycling these industrial by-products mitigates environmental pollution, reduces disposal costs, and provides economic benefits. Thus, this study advances both the scientific understanding and practical application of sustainable soil stabilization. Full article

To explore the effects of micro-nano aeration and oxygenation irrigation on soil characteristics and cotton growth in cotton fields in arid areas, this study was conducted at the National Soil Quality Aksu Observation and Experiment Station in Baicheng County, Xinjiang. “Xinluzao 78” cotton was used as the experimental material, and the soil column cultivation method was adopted. Four nitrogen concentration gradients (N0: 0 kg·hm⁻², NL: 112.5 kg·hm⁻², NM: 225 kg·hm⁻², and NH: 337.5 kg·hm⁻²) and two irrigation methods (micro-nano aeration and oxygenation irrigation Y: DO15 mg/L, conventional irrigation C: DO7.6 mg/L) were set up to systematically analyze the total nitrogen content of the soil, enzyme activity, microbial community structure, and the response characteristics of cotton growth and yield. The results show that aeration treatment significantly increases the total nitrogen content in the soil. The total nitrogen content in the 0–15 cm and 15–30 cm soil layers treated with YNM (aeration + local conventional nitrogen application rate) increased by 9.14% and 8.53%, respectively, compared with CNM. YNM treatment significantly increased the activities of soil urease, sucrase, and β-glucosidase, among which total nitrogen had the strongest correlation with the activity of β-glucosidase. Oxygenation significantly increased the richness of soil microorganisms. The Chao1 index of YNM-treated bacteria was 75.7% higher than that of CNM-treated bacteria. YNM treatment increased cotton yield by 26.73% compared with CNM treatment. Moreover, the number of bells formed per plant and the weight of the bells increased by 44.44% and 29.6%, respectively. In conclusion, micro-nano aeration and oxygenation irrigation effectively increase cotton yield. By optimizing the activities of soil enzymes and microorganisms, micro-nano aeration and oxygenation irrigation enhance the ability of cotton to utilize and transform nitrogen, and alleviate the impact of insufficient nitrogen utilization by cotton in arid areas. Full article

Biochar (BC), a carbonaceous material derived from biomass pyrolysis, exhibits a wide range of physicochemical properties, including a high cation exchange capacity, porosity, and specific surface area, which make it a highly valuable amendment for soil enhancement and environmental sustainability. As BC has shown strong potential to remediate soils, enhance their fertility, and increase crop productivity, it can successfully be used as a soil remediation factor. Additionally, it can play a critical role in carbon sequestration and climate change mitigation, revealing a high sorption capacity, multifunctionality, and long-term persistence in soils, where it can remain stable for hundreds to thousands of years. The present systematic review aims at presenting the dynamics of BC when incorporated into a soil system, focusing on its pH, water-holding capacity, aeration, microbiota, and carbon and nutrient availability across various case studies, particularly in acid, saline/sodic, and heavy metal-contaminated soils. Given the variability in BC performance, robust, long-term field-based research is essential to validate the current findings and support the development of targeted and sustainable biochar applications. Full article

The use of antibiotics in aquaculture is associated with significant environmental risks, including ecosystem disruption and the accumulation of antibiotics in reservoirs and soil cover, as well as the spread of antibiotic-resistant strains, which encourages the search for sustainable alternatives, such as probiotics. This review summarizes the research results on the use of probiotics in aquaculture systems. Special attention is paid to the action mechanisms and diverse effects on the health of aquatic animals, water quality and, most importantly, on the properties of soil in ponds. The research results show that certain strains of probiotics, in particular Bacillus spp., effectively decompose organic substances in sediments, reduce toxic metabolites’ concentration (ammonia, nitrites, hydrogen sulfide), stabilize soil structure, improve aeration and regulate sediments’ pH level and microbial diversity. However, the efficacy in field conditions can vary. Probiotics represent a science-based strategy to reduce dependence on antibiotics, increase system resilience by improving soil and water conditions, and increase productivity. In order to achieve maximum results, it is necessary to optimize the application methods, whilst taking into account local environmental factors. Full article

Soil erosion in granite-derived weathering mantles poses serious threats to slope stability and ecological sustainability in subtropical regions. While polyacrylamide (PAM) is widely used to improve soil structure, its concentration-dependent effects on multiple soil functions remain unclear. This study developed a multifunctional Soil Function Index (SFI) framework integrating erosion resistance (SFI₁), water regulation (SFI₂), and ecological function (SFI₃) to evaluate the effects of PAM application (0‰, 1‰, 3‰, 5‰, 7‰) on gully-prone sandy material. Herein, SFI₁ was quantified through shear strength (τ) and soil erodibility (K_r); SFI₂ was assessed using soil hydraulic parameters (saturated hydraulic conductivity and water retention curves) and SFI₃ was derived from the grass root system analysis. The results showed that SFI₁ and SFI₂ increased nonlinearly with PAM concentration, reaching maximum values of 0.983 and 0.980 at 7‰, with K_r reduced by 77.3% and non-capillary porosity (NAP) increased by 8.1%. In contrast, SFI₃ peaked at 0.858 under 3‰ and declined sharply to 0.000 at 7‰, due to micropore over-compaction, reduced aeration, and limited plant-available water. The total SFI exhibited a unimodal trend, with a maximum of 0.755 at 3‰, beyond which ecological suppression offset physical improvements. These findings demonstrate that PAM modifies soil multifunctionality through pore-scale restructuring, inducing function-specific thresholds and trade-offs. A PAM concentration of 3‰ is identified as optimal, achieving a balance between erosion control, hydrological performance, and ecological viability in the management of subtropical granite-derived sandy slopes. Full article

To explore the mechanisms by which water, fertilizers, and dissolved oxygen affect the physiological growth and yield quality of custard apple, this study aims to optimize water–fertilizer–oxygen coupling regulation schemes for custard apple in dry hot valley regions through a multi-level fuzzy evaluation method, thereby addressing issues such as soil compaction and reduced aeration caused by long-term water and fertilizer drip irrigation. The experiment was conducted on custard apple in a dry, hot valley area, employing orthogonal and quadratic regression-orthogonal designs. Three factors were set at multiple levels: irrigation amount (60–100% ETc), fertilization rate (1500–1900 kg·ha⁻¹), and dissolved oxygen concentration (6–10 mg·L⁻¹). Custard apple development, production, and attributes were assessed. The two-year trial from 2023 to 2024 demonstrated that the new shoots, leaf area, and net photosynthetic rate of plants treated with W3F2O1 (100% ETc, 1700 kg·ha⁻¹ fertilization rate, and high oxygen 6 mg·L⁻¹) and W3F3O2 (100% ETC, 1500 kg·ha⁻¹ fertilization rate, and high oxygen 8 mg·L⁻¹) were significantly superior to those of W1F1O1 (60% ETc, 1900 kg·ha⁻¹ fertilization rate, and high oxygen 6 mg·L⁻¹), with a single-plant yield of 10.31 kg, and increases in diameter and length of 31.6% and 27.6%, respectively (p < 0.05); quality indicators were also optimal under W3F3O2 (100% ETC, 1500 kg·ha⁻¹ fertilization rate, and high oxygen 8 mg·L⁻¹) treatment, with soluble sugar and vitamin C levels increasing by 17.3% and 29.9%, respectively, compared to the control. Using a multi-level fuzzy evaluation to comprehensively evaluate the water–fertilizer–oxygen coupling, the comprehensive productivity of custard apples was significantly improved by optimizing the root zone microenvironment. It is recommended that dry hot valleys adopt an optimized range of 82.5–100% ETc irrigation, 1650–1847.86 kg·ha⁻¹ fertilization, and 7.4–9.25 mg·L⁻¹ dissolved oxygen, providing a theoretical basis for precise irrigation and sustainable cultivation of tropical fruit trees. Full article

Optimizing aeration, fertilization, and irrigation is vital for improving greenhouse tomato production while mitigating soil greenhouse gas (GHG) emissions. This study investigated the combined effects of three aeration levels (A1: single Venturi, A2: double Venturi, CK: no aeration), two fertilization rates (F1: 180 kg/ha, F2: 240 kg/ha), and two irrigation levels (I1: 0.8 E_pan, I2: 1.0 E_pan) on tomato yield, CO₂, N₂O, and CH₄ emissions, net GHG emissions, net global warming potential (NGWP), and GHG intensity (GHGI) across Spring–Summer and Autumn–Winter seasons. Results showed that aeration and fertilization significantly increased CO₂ and N₂O emissions but reduced CH₄ emissions. Warmer conditions in Spring–Summer elevated all GHG emissions and yield compared to Autumn–Winter seasons. Tomato yield, net GHG emissions, NGWP, and GHGI were 12.05%, 24.3%, 14.46%, and 2.37% higher, respectively, in Spring–Summer. Combining the Maximal Information Coefficient and TOPSIS models, the optimal practice was A1-F1-I1 in Spring–Summer and A2-F1-I1 in Autumn–Winter seasons. These results provide a theoretical basis for selecting climate-smart management strategies that enhance yield and environmental sustainability in greenhouse tomato systems. Full article

Global agricultural intensification has exacerbated soil compaction and nitrogen (N) inefficiency, thereby threatening sustainable crop production. Sub-soiling, a tillage technique that fractures subsurface layers while preserving surface structure, offers potential solutions by modifying soil physical properties and enhancing microbial-mediated N cycling. This study investigated the effects of subsoiling depth (0, 20, and 40 cm) on soil microbial communities and N transformations in a semi-arid maize system in China. The results demonstrated that subsoiling to a depth of 40 cm (D2) significantly enhanced the retention of nitrate-N and ammonium-N, which correlated with improved soil porosity and microbial activity. High-throughput 16S rDNA sequencing revealed subsoiling depth-driven reorganization of microbial communities, with D2 increasing the abundance of Proteobacteria (+11%) and ammonia-oxidizing archaea (Nitrososphaeraceae, +19.9%) while suppressing denitrifiers (nosZ gene: −41.4%). Co-occurrence networks indicated greater complexity in microbial interactions under subsoiling, driven by altered aeration and carbon redistribution. Functional gene analysis highlighted a shift from denitrification to nitrification-mineralization coupling, with D2 boosting maize yield by 9.8%. These findings elucidate how subsoiling depth modulates microbiome assembly to enhance N retention, providing a mechanistic basis for optimizing tillage practices in semi-arid agroecosystems. Full article

The conversion of wetlands into croplands often leads to significant losses of peat soil salinity and soil organic matter (SOM), though quantifying these changes is challenging due to limited historical data. In this study, we compared current soil physicochemical properties with rare historical data from the Mezzano Lowland (ML) in Northeastern Italy, a former wetland drained over 60 years ago. The transformation, which affected approximately 18,100 hectares, was achieved through the construction of a network of drainage canals and pumping stations capable of removing large volumes of water, enabling intensive agricultural use. Results showed a marked decrease in electrical conductivity (EC) and sulphate concentration, indicating extensive salt leaching from the upper peat soil layers. EC dropped from historical values up to 196 $\mathrm{m}$$\mathrm{S}$/cm (1967–1968) to a current maximum of 4.93 $\mathrm{m}$$\mathrm{S}$/cm, while sulphate levels declined by over 90%. SOM also showed significant depletion, especially in deeper layers (50–100 cm), with losses ranging from 50 to 60 $\mathrm{wt}\%$, due to increased aeration and microbial activity post-drainage. These climatic and environmental changes, including a marked reduction in soil salinity and sulphate concentrations due to prolonged leaching, have likely shifted the Mezzano Lowland from a carbon sink to a net source of CO₂ and CH₄ by promoting microbial processes that enhance methane production under anaerobic conditions. To detect residual peat layers, we used Ground-Penetrating Radar (GPR), which, combined with soil sampling, proved effective for tracking long-term peat soil changes. This approach can inform sustainable land management strategies to prevent further carbon loss and maintain peat soil stability. Full article

Although nitric oxide (NO) production in bacteria has traditionally been associated with denitrification or stress responses in model or symbiotic organisms, functionally validated L-arginine-dependent nitric oxide synthase (bNOS) activity has not been documented in free-living, non-denitrifying soil bacteria. This paper reports Paenibacillus nitricinens sp. nov., a bacterium isolated from rainforest soil capable of synthesizing NO via a bNOS under aerobic conditions. A bnos-specific PCR confirmed gene presence, while whole-genome sequencing (6.7 Mb, 43.79% GC) revealed two nitrogen metabolism pathways, including a bnos-like gene. dDDH (<70%) and ANI (<95%) values with related Paenibacillus strains support the delineation of this isolate as a distinct species. Extracellular and intracellular NO measurements under aerobic conditions showed a dose-dependent response, with detectable production at 0.1 µM L-arginine and saturation at 100 µM. The addition of L-NAME reduced NO formation, confirming enzymatic mediation. The genomic identification of a bnos-like gene strongly supports the presence of a functional pathway. The absence of canonical nitric oxide reductase (Nor) genes or other typical denitrification-related enzymes reinforces that NO production arises from an alternative, intracellular enzymatic mechanism rather than classical denitrification. Consequently, P. nitricinens expands the known repertoire of microbial NO synthesis and suggests a previously overlooked source of NO flux in well-aerated soils. Full article

Orchard cover crops enhance the local microclimate and soil fertility, serving as an eco-friendly, efficient management practice. However, the effects of different cultivated species and planting patterns on plant growth and soil properties remain unclear. In this study, we hypothesized that different cultivated species and planting patterns would differently affect root growth and soil biochemistry. Therefore, the root growth, soil nutrients, and soil metabolites in an orchard planted with Vulpia myuros, Vicia villosa, Orychophragmus violaceus, and Brassica campestris in either a tree-disk or inter-row patterns were conducted. The results indicated that the tree-disk pattern promoted root development. This increase in below-ground biomass contributed to changes in soil nutrient dynamics, with a significant biomass accumulation observed for Orychophragmus violaceus. While the inter-row pattern improved soil aeration and was conducive to aboveground plant growth. The tree-disk pattern with Vicia villosa and Brassica campestris increased the total phosphorus (TP) and total potassium (TK) in the 0–10 cm layer. The soil NH₄⁺-N and NO₃⁻-N contents were higher under the tree-disk pattern than under the inter-row pattern with Brassica campestris, whereas the opposite effect was seen with Vulpia myuros. Overall, we recommend planting Orychophragmus violaceus in a tree-disk pattern and Vulpia myuros in an inter-row pattern to promote plant biomass accumulation and soil nutrient increases in orchards. Our study provides a basis for the selection of orchard-cultivated species and planting patterns to promote the sustainable development of the fruit industry. Full article