Search Results (58)

Soil viruses are increasingly recognized as key regulators of microbial communities and biogeochemical cycles, yet their responses to long-term fertilization strategies remain poorly characterized. We conducted a four-year pot experiment in subtropical China to evaluate how chemical fertilizer (CF), biochar (BC), and organic fertilizer (OF) application influenced soil viromes compared with an unfertilized control (CK) treatment. Metagenomic analyses recovered 1581 viral contigs with distinct community structures across treatments. Lytic viruses dominated overall, with higher proportions in BC and OF treatments, positively correlated with soil fertility indicators. Diversity indices indicated that BC and OF treatments significantly enhanced viral richness and evenness relative to CK and CF treatments, reflecting broader microbial host niches. Virus–host link predictions revealed expanded networks under BC and OF treatments, particularly with Pseudomonadota, Cyanobacteriota, and Acidobacteriota, suggesting amendment-specific viral regulation. Functional annotation showed that OF and BC application enriched viral KEGG categories related to metabolism, transport, and signal transduction. Moreover, BC and OF application promoted nitrate reduction, nitrogen fixation, and phosphorus mobilization. Together, these findings highlight organic amendments as critical drivers of soil viral diversity and functional potential, linking viromes dynamics to sustainable nutrient cycling in agroecosystems. Full article

In agricultural systems, excessive application of nitrogen fertilizer often leads to low nitrogen use efficiency and environmental pollution. In order to solve this problem, we studied the synergistic effect of biochar and nitrogen fertilizer on pepper yield, quality and rhizosphere soil health. This study was conducted under a temperate continental monsoon climate in Changchun, China. Using ‘Jinfu 803’ pepper (Capsicum annuum L.) as the test material, biochar was prepared from corn straw under oxygen-limited conditions at 500 °C. the comprehensive effects of the combined application of biochar (0, 0.7% soil mass ratio) and nitrogen fertilizer (0, 75, 375, 675 kg/hm² pure nitrogen) on pepper yield, fruit quality, rhizosphere soil physicochemical properties, and microbial community structure were studied. Redundancy analysis (RDA), high-throughput sequencing, and multivariate statistical methods were used to analyze the association patterns between soil environmental factors and microbial functional groups. The results showed that the combined application of biochar and nitrogen fertilizer significantly improved soil porosity (increased by 12.3–28.6%) and nutrient content, increased yield, and improved quality, among which the treatment of 0.7% biochar combined with 375 kg/hm² nitrogen fertilizer (B1N2) had the best effect. Under this treatment, the pepper yield reached 24,854.1 kg/hm², which was 42.35% higher than that of the control (B0N0). Notably, the nitrogen partial factor productivity (PFPN) of the B1N2 treatment (66.3 kg/kg) was significantly higher than that of the corresponding treatment without biochar and was not significantly lower than that of the high-nitrogen B1N3 treatment. The contents of soluble sugar and vitamin C in fruits increased by 51.18% and 39.16%, respectively. Redundancy analysis (RDA) revealed that the bacterial community structure was primarily shaped by soil pH, organic matter, and porosity, while the fungal community was predominantly influenced by alkaline hydrolyzable nitrogen and total nitrogen. Furthermore, the B1N2 treatment specifically enriched key functional microbial taxa, such as Chloroflexi (involved in carbon cycling) and Mortierellomycota (phosphate-solubilizing), which showed significant positive correlations with improved soil properties. In conclusion, B1N2 is the optimal treatment combination as it improves soil physical conditions, increases nutrient content, optimizes microbial community structure, and enhances pepper yield and quality. Full article

Excessive phosphate from agriculture and industry has led to widespread eutrophication, posing a serious environmental threat. To address this issue, metal-modified biochars have emerged as promising adsorbents due to their high affinity for phosphate ions. This study investigates the application of two magnesium-modified biochar hydrogels denoted as magnesium–bamboo biochar hydrogel (Mg-BBH) and magnesium–pulp biochar hydrogel (Mg-PBH) for phosphate recovery from aqueous solutions, with an additional aim as slow-release fertilizers. The adsorbents were synthesized by impregnating Mg-modified biochars into sodium-alginate-based hydrogel. The influence of initial phosphate concentration, contact time, and temperature were investigated to determine optimal adsorption conditions. Both adsorbents exhibited excellent adsorption performance, with maximum capacities of 309.96 mg PO₄/g (Mg-BBH) and 234.69 mg PO₄/g (Mg-PBH). Moreover, the adsorption performance of the adsorbents was greatly influenced by the magnesium content. The adsorption process followed the Temkin isotherm and pseudo-second-order kinetics, suggesting that the adsorption energy decreases proportionally with surface coverage and the phosphate uptake was governed by chemisorption. Thermodynamic study confirmed the process was spontaneous and endothermic at 40 °C. A slow-release study further demonstrated a great release of phosphate in soil over time. These findings highlight the dual functionality of Mg-BBH and Mg-PBH as effective materials for both phosphate recovery and controlled nutrient delivery, contributing to sustainable phosphate management. Full article

This study investigates biochar-enriched organic fertilizers made from bagasse, ash, spent wash, and cane tops, assessing their impact on corn growth over 45 days. A randomized complete block design with three replicates was used, testing six formulations with biochar levels at 0%, 10%, and 20%, along with soil-only and commercial fertilizer controls. Treatments T5 (bagasse + ash + spent wash + cane tops), T11 (T5 + 10% biochar), and T17 (T5 + 20% biochar) showed the best results for plant height, leaf development, and biomass production, with T17 performing the best for growth, biomass, and girth. The biochar in T17 had a pH of 9.37 ± 0.16, 18.00 ± 1.25% ash content, and a surface area of 144.58 m²/g. Nutrient analysis of the compost showed 2.85% potassium, 1.12% phosphorus, 1.85% nitrogen, 4.1% calcium, 0.23% magnesium, and 130 mg/kg zinc. The elemental composition was 68.50% carbon, 4.50% hydrogen, 6.00% nitrogen, and 25.30% oxygen, with 85.00% total organic carbon (TOC). This study concludes that T17 is the most effective formulation, offering both environmental and financial benefits, with composting potentially generating $11.16 million in profit, compared to the $19.32 million spent annually on waste management in Sri Lanka’s sugar industry. Full article

Biochar-based fertilizers can improve soil structure and fertility. However, their efficiency is affected by the raw materials of biochar. The effects of biochar-based fertilizers on the soil microenvironment under Fenlong-ridging conditions remain unclear. This study aimed to evaluate the effects of biochar-based fertilizers derived from sugarcane filter mud and rice straw on soil physicochemical properties, microbial communities, and sugarcane yield under Fenlong-ridging in Guangxi’s acidic red soil (Hapludults). A two-year field experiment (2021–2022) was conducted on a clay loam soil classified as Hapludults (USDA Soil Taxonomy) in the same experimental plots using three fertilizer applications—conventional chemical fertilization (CK), straw biochar-based fertilizer (T1), and sugar filter mud biochar-based fertilizer (T2)to determine the responses of soil physicochemical properties and bacterial community diversity to different biochar-based fertilizers and evaluate benefits to the soil environment and sugarcane yield. Soil samples (0–20 cm depth) revealed that T1 and T2 reduced bulk density by 2.31% and increased porosity by 2.00–2.31% versus CK. Notably, T2 exhibited 4.1-fold higher specific surface area than T1, driving stronger soil–bacterial interactions: it enhanced soil moisture (7.17–13.05%) and pH (17.89–24.14% in 2021; 8.68–11.57% in 2022), thereby promoting nutrient availability (N, P, K), organic matter (SOM), and sucrase activity. Microbiome analysis showed T2 enriched Gemmatimonadota and Sphingomonas (beneficial taxa) while suppressing Acidothermus. The results of RDA and Spearman correlation analysis indicated that the bacterial community structure was mainly affected by soil pH, TN, AP, and SOM. Consequently, T2 increased sugarcane yield by 5.63–11.16% over T1 through synergistic soil–microbial improvements. Future studies involving multi-site and long-term experiments are needed to confirm the broader applicability and stability of these findings. This study provides a theoretical basis for the positive regulation of sugar filter mud biochar-based fertilizers in the soil environment, bacterial community structure, and sugarcane yield. Full article

The gleyed paddy soils in subtropical China, characterized by poor structure, high reductive substances, and low fertility, pose challenges to sustainable agriculture. This study investigates the improvement effects of applying rapeseed green manure in combination with biochar or vermicompost through field experiments, aiming to provide a theoretical basis for the organic improvement of gleyed paddy soils. The experiment included four treatments: control (CK), rapeseed green manure (GM), GM + biochar (GMB), and GM + vermicompost (GMVC). Soil physicochemical properties, aggregate stability, and fungal communities were analyzed after rice harvest. GM significantly increased the total nitrogen (TN) content in the 0–10 cm soil layer and decreased the Fe²⁺ and total glomalin-related soil protein (T-GRSP) contents. GMVC further increased the pH value, available potassium (AK) content, and Shannon index in the 0–10 cm soil layer, decreased the available phosphorus (AP) content, and increased the proportion of macro-aggregates (>2000 µm) and decreased the fractal dimension (D) in the 10–20 cm soil layer. Compared with GMVC, GMB more significantly increased the soil organic carbon content and regulated the ratio of EE-GRSP/T-GRSP in the 0–10 cm soil layer. Fungal community analysis showed Ascomycota dominance. Pearson analysis showed Westerdykella enrichment significantly correlated with reduced T-GRSP. Monte Carlo tests identified pH and SOC as key factors shaping fungal communities. The GMB strategy mitigates reductive stress, enhances nutrient availability, and activates microbial functionality. These findings offer insights and frameworks for sustainable soil management in subtropical rice agroecosystems. Full article

Elevated phosphorus levels in aquatic ecosystems have been identified as a critical driver of eutrophication processes, necessitating resource-recovery remediation strategies. Adsorption techniques show particular promise for nutrient recovery due to their selective binding capacities and operational feasibility. In this study, the Mg- and Ca-modified biogas residue-based biochar (Ca-Mg/BC) was successfully prepared via a “bimetallic loading-pyrolysis” modification strategy. The optimum temperature for the calcination of the material and the salt solution impregnation concentrations were determined experimentally through optimization of the synthesis conditions. Structural and chemical analyses of Ca–Mg/BC demonstrated that the material contains MgO and CaO. The specific surface area of Ca–Mg/BC was 8.49 times higher than that of the unmodified biochar (BC). The optimized Ca–Mg/BC achieved 95% phosphate removal rate (157.13 mg/g adsorption capacity). FTIR and XPS characterization results indicated the importance of Ca/Mg loading in phosphate capture. MgO and CaO were mainly loaded on the surface of the material and adsorbed phosphate through a chemical reaction. Crucially, the phosphate-laden biochar exhibited potential as a nutrient-enriched soil amendment, opening the material loop from wastewater treatment to agricultural applications. This sustainable strategy simultaneously addresses water pollution control and sustainable development, providing environmentally benign solutions compatible with industrial effluent treatment and sustainable agriculture practices. Full article

The development of sustainable seed coating formulations is essential to enhance crop performance while reducing reliance on synthetic inputs. This study evaluates biochar-enriched coatings incorporating olive pomace, buffalo digestate, and microbial consortia from Fagus, Quercus, and Pinus forest litters, including Trichoderma harzianum, for their effects on seed germination and plant growth. Four crops (Diplotaxis tenuifolia, Lactuca sativa, Solanum lycopersicum, and Zea mays) were tested through germination assays and field trials. Treatments containing digestate or pomace alone significantly reduced germination and seedling growth in D. tenuifolia and L. sativa (below 25%, compared to control), due to the phytotoxic effects of ammonia, salts, and polyphenols. In contrast, biochar-based coatings mitigated these effects, enhancing germination and root elongation. The addition of T. harzianum further improved seedling establishment, likely by enhancing nutrient uptake and suppressing soilborne pathogens, with increases exceeding 100% (compared to control). Field trials confirmed these findings, showing that biochar–T. harzianum combinations improved both shoot and root biomass, particularly in L. sativa and S. lycopersicum. Z. mays displayed greater tolerance to raw by-products, though biochar remained essential for optimal growth. While forest-derived microbial consortia supported microbial balance, their effect on biomass was less pronounced. These results highlight the potential of biochar-based coatings, especially when combined with T. harzianum, as sustainable alternatives to conventional seed treatments. Full article

Tomato is a major crop, and efforts are ongoing to enhance its resilience to biotic and abiotic stresses. Weed management remains a key challenge, prompting the search for sustainable alternatives to reduce the impact of excessive herbicide use. Biochar is a promising alternative, as it enriches the soil, improves its water retention capacity, promotes its regeneration and increased fertility, delays nutrient leaching, and improves fertilizer use efficiency. This study aimed to investigate the efficiency of biochar use in mitigating stress caused by different herbicides. Two different biochar materials, Douglas fir and rice husk, were used. Tomato seeds were sown in pots and arranged in a randomized design. At the 4V stage (28 days after sowing), the herbicides S-metolachlor, metribuzin, and halosulfuron were applied. Plant length, injury, antioxidant enzyme activity, ascorbate peroxidase (APX), catalase (CAT), guaiacol peroxidase (GPOD), glutathione reductase (GR), and hydrogen peroxide content (H₂O₂) were assessed 7 and 14 days after herbicide application. Plants treated with biochar and submitted to herbicide treatments showed significantly higher growth parameters and fewer injuries when compared to plants treated with herbicides without biochar. The antioxidant response of the plants followed the same trend; smaller plants with more injuries showed greater H₂O₂ accumulation and significantly higher antioxidant enzyme activity. These findings highlight the protective effect of biochar, particularly Douglas fir biochar, as it effectively mitigated herbicide-induced oxidative stress and helped maintain plant growth and structural integrity under treatment conditions. Full article

Biochar, an eco-friendly soil amendment, holds promise for remediating contaminated soils, yet its impacts on coastal wetland soils under combined microplastic (MP) and heavy metal (HM) pollution remain underexplored. This study examined the efficacy of 2% Spartina alterniflora-derived biochar (BC) in rehabilitating soils co-contaminated with cadmium (Cd) and two MPs—polyethylene (PE) and polylactic acid (PLA)—at 0.2% and 2% (w/w). The results indicated that biochar significantly elevated soil pH (8.35–8.43) and restored electrical conductivity (EC) to near-control levels, while enhancing organic matter content (up to 130% in PLA-contaminated soils), nutrient availability (e.g., phosphorus, potassium), and enzyme activity. Biochar reduced bioavailable Cd by 14–15% through adsorption and ion exchange. Although bacterial richness and diversity slightly declined, biochar reshaped microbial communities, enriching taxa linked to pollutant degradation (e.g., Proteobacteria, Bacteroidota) and upregulated functional genes associated with carbon, nitrogen, and sulfur cycling. Additionally, biochar boosted Suaeda salsa (S. salsa) biomass (e.g., 0.72 g/plant in A1B) and height (e.g., 14.07 cm in E1B) while reducing Cd accumulation (29.45% in shoots) and translocation. Remediation efficiency was most pronounced in soils with 0.2% PLA. These findings bridge critical knowledge gaps in biochar’s role in complexly polluted coastal wetlands and validate its potential for sustainable soil restoration. Full article

The projected growth of the global population to over 10 billion by 2080 necessitates groundbreaking sustainable agricultural solutions that enhance productivity while mitigating environmental impacts. Tenebrio molitor frass (TMF), derived from larval excrement and exuviae, has emerged as a promising organic fertilizer. Enriched with macro- and micronutrients, TMF enhances soil functions through microbial communities that promote nutrient cycling, decompose organic matter, and suppress soilborne pathogens. Additionally, functional compounds like chitin, cellulose, xylans, and lignin improve the soil structure, foster beneficial microbes, and activate natural plant defence responses. The synergy of microbial activity and bioactive compounds positions TMF as a valuable resource for enhancing plant growth and soil health. Its role as a nutrient source, biostimulant, and soil amendment aligns with circular economy principles by recycling agro-industrial by-products and reducing reliance on synthetic fertilizers. TMF also contributes to sustainable agriculture by improving soil fertility, microbial biodiversity, and plant stress resilience, while mitigating greenhouse gas emissions and nutrient runoff. Additionally, TMF-derived biochar offers the potential for environmental remediation as an effective adsorbent. Despite its advantages, TMF faces challenges in scalability, cost, and regulations, requiring advancements in processing, enrichment, and supportive policies to maximize its potential in sustainable farming. Full article

The pyrolysis process of residues has emerged as a sustainable method for managing organic waste, producing biochars that offer significant benefits for agriculture and the environment. These benefits depend on the properties of the raw biomass and the pyrolysis conditions, such as washing and drying. This study investigated biochar production through slow pyrolysis at 300 °C, using eight biomass types, four being plant residues (PBR)—sugarcane bagasse, filter cake, sawdust, and stranded algae—and four non-plant-based residues (NPBR)—poultry litter, sheep manure, layer chicken manure, and sewage sludge. The physicochemical properties assessed included yield, carbon (C) and nitrogen (N) content, electrical conductivity, pH, macro- and micronutrients, and potentially toxic metals. Pyrolysis generally increased pH and concentrated C, N, phosphorus (P), and other nutrients while reducing electrical conductivity, C/N ratio, potassium (K), and sulfur (S) contents. The increases in the pH of the biochars in relation to the respective biomasses were between 0.3 and 1.9, with the greatest differences observed for the NPBR biochars. Biochars from sugarcane bagasse and sawdust exhibited high C content (74.57–77.67%), highlighting their potential use for C sequestration. Filter cake biochar excelled in P (14.28 g kg⁻¹) and micronutrients, while algae biochar showed elevated N, calcium (Ca), and boron (B) levels. NPBR biochars were rich in N (2.28–3.67%) and P (20.7–43.4 g kg⁻¹), making them ideal fertilizers. Although sewage sludge biochar contained higher levels of potentially toxic metals, these remained within regulatory limits. This research highlights variations in the composition of biochars depending on the characteristics of the original biomass and the pyrolysis process, to contribute to the production of customized biochars for the purposes of their application in the soil. Biochars derived from exclusively plant biomasses showed important aspects related to the recovery of carbon from biomass and can be preferred as biochar used to sequester carbon in the soil. On the other hand, biochars obtained from residues with some animal contributions are more enriched in nutrients and should be directed to the management of soil fertility. Full article

This study evaluates the use of biochar as a sustainable substitute to peat in the soilless cultivation of rocket salad (Eruca vesicaria (L.) Cav.). Biochar was added to a peat-based substrate at concentrations of 0% (control), 5%, 10%, 20%, 40%, and 70% v/v to assess its effects on seed germination, plant growth, mineral content, and nitrate accumulation. The results show that biochar concentrations up to 40% v/v maintained germination rates above 80%, similar to the control, while higher concentrations (70% v/v) drastically reduced germination to 29% and entirely compromised plant development and growth. A moderate biochar concentration (20%) had a positive effect on fresh weight and leaf area, while maintaining comparable levels of nutrient uptake, chlorophyll, and flavonols. In addition, biochar-enriched substrates (≥20% v/v) reduced nitrate accumulation in leaves by 26–30%, addressing a critical quality and safety concern. A high biochar content (≥40% v/v) altered the substrate’s physicochemical properties, including pH, porosity, and electrical conductivity, negatively affecting plant growth (a 38% reduction in plant growth and 42% in leaf area) and increasing heavy metal concentrations, such as that of zinc (~30%). These findings suggest that incorporating up to 20% v/v biochar in soilless substrates offers a sustainable alternative to peat, supporting rocket salad performance and improving leaf nitrate quality, without compromising yield or safety. Full article

The potential of biochar to mediate shifts in soil microbial communities caused by polycyclic aromatic hydrocarbon (PAH) stress in farmland, thus assisting in the bioremediation of contaminated soil, remains uncertain. This study introduced wheat straw biochars generated at 300 °C (W300) and 500 °C (W500) at varying levels (1% and 2% w/w) into agricultural soil contaminated with phenanthrene at 2.5 and 25 mg/kg. The aim was to investigate their effects on microbial community structure and phenanthrene degradation by indigenous microbes. Biochar application in both slightly (PLS) and heavily (PHS) contaminated soils increased overall microbial/bacterial biomass, preserved bacterial diversity, and selectively enriched certain bacterial genera, which were suppressed by phenanthrene stress, through sorption enhancement and biotoxicity alleviation. The abundances of PAH-degrading genera and nidA degradation gene were promoted by biochar, especially W300, in PHS due to soil nutrient improvement, enhancing phenanthrene biodegradation. However, in PLS, biochar, particularly W500, inhibited their abundance due to a reduction in phenanthrene bioavailability to specific degraders, thus hindering phenanthrene biodegradation. These findings suggest that applying wheat straw biochar produced at appropriate temperatures can benefit soil microbial ecology and facilitate PAH elimination, offering a sustainable strategy for utilizing straw resources and safeguarding soil health and agricultural product quality. Full article

This work aimed to explore safe techniques for the utilization of farmland surrounding mining areas contaminated with heavy metals—specifically cadmium (Cd) and lead (Pb)—in order to achieve food security in agricultural production. A potato variety (Qingshu 9) with high Cd and Pb accumulation was used as the test crop, and seven treatments were set up: control (CK), special potato fertilizer (T1), humic acid (T2), special potato fertilizer + humic acid (T3), biochar (T4), calcium magnesium phosphate fertilizer (T5), and biochar + calcium magnesium phosphate fertilizer (T6). The remediation effect of the combined application of different passivators on the accumulation of cadmium and lead in potatoes in the contaminated soil of a mining area was studied. The results showed that, compared with CK, all passivator treatments improved the physical and chemical properties of the soil and reduced the available Cd and Pb content in the soil and in different parts of potatoes. The T6 treatment yielded the most significant reduction in the available Cd and Pb content in the soil, the Cd and Pb content in the potato pulp, and the enrichment factor (BCF) and transfer factor (TF) of the potatoes. Compared with T4 and T5, the content of available Cd in the soil decreased by 1.22% and 4.71%, respectively; the soil available Pb content decreased by 3.13% and 3.02%, respectively; the Cd content in the potato pulp decreased by 68.08% and 31.02%, respectively; and the Pb content decreased by 31.03% and 20.00%, respectively. The results showed that the application of biochar combined with calcium magnesium phosphate fertilizer had a better effect in terms of reducing the available Cd and Pb content in the soil and the Cd and Pb content in the potato flesh compared to their individual application. Biochar and calcium magnesium phosphate fertilizer can synergistically increase the content of soil available nutrients and reduce the activity of heavy metals in the soil to prevent the transfer and accumulation of cadmium and lead to potatoes, as well as improve their yield and quality. The results of this study provide technical support for safe potato planting and agricultural soil management. Full article