Search Results (457)

In the process of anaerobic digestion for manure treatment, adding conductive materials is one of the most used methods to enhance methane yield. Biochar, a stable conductive material, shows significant potential in facilitating direct interspecies electron transfer in anaerobic digestion systems. However, biochar’s structure and properties are influenced by its preparation method, and the mechanisms by which structural characteristics affect methane yield and microbial community structure in fermentation systems require further investigation. This study investigates the effects of pyrolysis duration (1 h for A3O and 2 h for A3T) at 550 °C using corn straw as raw material. Through characterization analyses including SEM, FTIR, conductivity, and elemental composition, we explore the impacts on gas production efficiency and key parameters in anaerobic digestion systems. By analyzing microbial community structure and changes in methanogenic functional bacteria, we elucidate the mechanisms by which biochar materials with different pyrolysis times influence anaerobic digestion processes and microbial community composition. These findings provide theoretical foundations and support for optimizing biochar preparation techniques and their targeted applications in anaerobic digestion fields. It was found that the biochar-treated group exhibited higher methane production. Compared with the CK group without biochar, the methane production of A3O and A3T increased by 8.53% and 5.16%, respectively. While methane yield differed little between A3O and A3T, longer pyrolysis time increased the biochar’s specific surface area, promoting the system’s reaction rate and enabling faster methanogenesis. High-throughput analysis showed that biochar enriched methanogenic archaea like Methanosarcina and Methanobrevibacter while upregulating methanogenesis metabolic pathways and enhancing system metabolic potential. This study elucidates the influence of pyrolysis conditions on biochar performance and its regulatory role in anaerobic digestion, providing a basis for energy recovery from organic waste and biochar application in anaerobic fermentation. Full article

In this study, pristine biochar (BC1) and magnesium-modified biochar (BC2) were prepared from corn straw. Different nitrogen deposition intensities (0, 8, 30, and 50 kg N/(ha·yr)) were simulated by adding NH₄NO₃ solution. A laboratory incubation experiment was conducted to investigate the effects of biochar addition and N deposition on CO₂ emissions, CH₄ uptake, and microbial community structure in soils from a temperate mixed conifer–broadleaf forest. The results showed that BC1 significantly increased cumulative CO₂ emissions (p < 0.05), while no significant difference was observed between BC2 and the control. N deposition had no significant effect on CO₂ emissions. Biochar addition significantly promoted cumulative CH₄ uptake (p < 0.05), with BC2 exhibiting a stronger promoting effect than BC1. In contrast, N deposition significantly inhibited CH₄ uptake (p < 0.05) in a dose-dependent manner. Spearman’s correlation analysis revealed that cumulative CO₂ emissions were significantly or highly significantly negatively correlated with the relative abundances of Elusimicrobiota, Actinomycetota, Chloroflexota, Planctomycetota, Acidibacter, Bacillus, Paenibacillus, Acidothermus, and Mycobacterium, and significantly positively correlated with Bacteroidota, Bdellovibrionota, Pseudomonadota, Devosia, and Mesorhizobium. Cumulative CH₄ uptake was highly significantly positively correlated with the relative abundance of Bacteroidota and significantly negatively correlated with Chloroflexota, Candidatus_Eremiobacterota, and Mycobacterium. These findings demonstrate that N deposition has no significant impact on soil CO₂ emissions but significantly inhibits CH₄ uptake, while magnesium-modified corn straw biochar promotes CH₄ uptake without substantially increasing CO₂ emissions, highlighting its promising application potential. Full article

Straw returning is an effective means of improving soil structure and increasing soil organic matter content. However, few studies have been conducted on the effects of corn straw returning on the soil microorganism community in soybean crops. In this paper, taking conventional combined tillage (CT) as a control, the effects of no-tillage with straw mulching (NTS), no-tillage with stubble retention (NT), and deep plowing with straw incorporation (DT) on soil bacterial community under a corn–soybean rotation system were studied. The results showed that the contents of soil total nitrogen, total phosphorus, available phosphorus, the activities of soil urease and acid phosphatase, and soil bacterial richness and diversity in the NTS treatment were significantly higher than those in other treatments. Moreover, the NTS treatment increased the abundance of Acidobacteriota and MND1 (unclassified bacterial genus) in the soil. The number of unique OTUs in the NTS treatment was the greatest (26.67%), with that of the CT treatment being the smallest (7.22%). Redundancy analysis (RDA) revealed that soil total nitrogen, total phosphorus, and available phosphorus are the key driving changes in bacterial community. Consequently, NTS treatment was the optimal approach for both soil fertility improvement and bacterial community optimization. This approach combines straw mulching and no-tillage, which not only exerts the nutrient supply effect of straw but also reduces the impact of soil disturbance on microbial habitats. Full article

This study investigated the effects of isoacid supplementation on in vitro rumen fermentation characteristics, nutrient degradability, and bacterial community diversity in yaks using corn silage–highland barley straw-based substrates. An in vitro fermentation experiment was conducted with a substrate consisting of 80% whole-plant corn silage and 20% highland barley straw. Treatments included a control (without isoacids) and four isoacid supplemental levels (0.1%, 0.2%, 0.3%, and 0.4% of substrate dry matter, DM), each with six replicates. A 72 h in vitro gas production experiment was performed to measure cumulative gas production, fermentation parameters, nutrient degradability, and bacterial community diversity. Cumulative gas production increased by 12.96% with 0.2% isoacid supplementation compared to the control (p < 0.05). The contents of microbial protein (MCP), acetate, propionate, and total volatile fatty acids (TVFA) exhibited quadratic responses to the increasing isoacid dosage (p < 0.05). Specifically, MCP content reached a maximum of 0.76 mg/mL with 0.2% isoacids, representing a 31.03% increase compared to the control (p < 0.05). TVFA content was highest (146.85 mmoL/L) at 0.2% isoacid supplementation, with a 16.40% increase compared to the control (p < 0.05). Acetate content increased by 17.99% (p < 0.05), while propionate tended to increase with 0.2% isoacid supplementation (p = 0.08). Supplementation with 0.2% and 0.4% isoacids did not alter the bacterial composition and diversity (p > 0.05). However, at the genus level, g_Ruminococcus, g__Elusimicrobium, g_norank_f_Atopobiaceae, g_norank_o_Coriobacteriales, and g_Romboutsia were identified as differential biomarkers showing significant responses to isoacid supplementation (p < 0.05). Mantel-test analysis revealed positive correlation between g_Ruminococcus abundance and NH₃-N content (r < 0.4, p < 0.05); g_Romboutsia abundance and acetate content (r < 0.40, p < 0.05); g_Defluviitaleaceae_UCG-011 abundance and both NH₃-N content and the pH of rumen fluid (r < 0.40, p < 0.05); g_norank_o_Coriobacteriales abundance and rumen pH (r < 0.40, p < 0.01). Supplementation with 0.2% isoacids to corn silage–barley straw substrates improved in vitro rumen fermentation characteristics in yaks, which was associated with altered abundances of key bacterial genera including g_Ruminococcus, g__Elusimicrobium, g_norank_f_Atopobiaceae, g_norank_o_Coriobacteriales. Full article

This study experimentally investigated the movement, combustion, and potassium (K) and chlorine (Cl) migration behaviors of three biomass types: densified wood pellets (heavy), corn straw (lightweight), and wheat straw (lightweight, friable). The experiments were conducted under conditions representative of industrial coal-fired circulating fluidized bed (CFB) boilers, with a temperature range of 850–950 °C and a fluidization velocity of 6–8 m/s. Results show that densified wood pellets sink into the dense-phase zone and release volatiles slowly, in about 50 s. As the volatiles are nearly fully released, the pellets fracture multiple times along their length, eventually forming nearly spherical particles. Their movement and combustion processes closely resemble those of coal, making them suitable for direct co-firing in coal-fired CFB boilers. Conversely, corn straw and wheat straw exhibit low density, high volatile release rates (2 and 10 times that of wood pellets, respectively), rapid char fragmentation and abrasion, and high inherent K and Cl content (with >50% of K and >90% of Cl released). These properties lead to particle segregation, shortened gas-phase combustion time, an upward shift in heat release distribution, and potential risks such as high-temperature KCl corrosion, HCl dew point corrosion, ash slagging, and bed agglomeration. Therefore, untreated corn straw and wheat straw are unsuitable for co-firing in conventional coal-fired CFB boilers. This study provides essential data and engineering guidance: strict quality control is necessary for wood pellets to prevent Cl contamination, while pretreatment is mandatory for straw fuels. These findings offer practical insights for implementing diverse biomass co-firing strategies in coal-fired CFB boilers. Full article

Biochar provides a porous scaffold, conductive carbon framework and redox-active surface functional that can promote microbial attachment and extracellular electron flow. However, how feedstock-dependent biochar properties regulate the biochar–cell interface and microbial metabolism during contaminant removal remains insufficiently understood. Here, biochar derived from rice husk, corn straw and corn cob was used to immobilize Pseudomonas chlororaphis for triclocarban removal in batch microcosms. Multiscale analyses, including scanning electron microscopy (SEM), fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), cyclic voltammetry (CV), (electrochemical impedance spectroscopy (EIS) and liquid chromatography–mass spectrometryLC-MS, were combined to link the biochar structure, interface and extracellular metabolism signatures with triclocarban (TCC) removal. Compared with free cells, all composites enhanced TCC removal and exhibited altered interfacial functional-group features together with substantially reduced fitted charge-transfer resistance, indicating facilitated interfacial electron exchange. Untargeted metabolomics further revealed consistent remodeling of extracellular redox-associated metabolite signatures upon immobilization, with increased quinone/polyphenol-associated features and pathway-level shifts related to redox homeostasis. Among feedstocks, the corn cob composite showed the highest triclocarban removal. Overall, this work proposes an evidence-supported “structure–interface–metabolism” framework for interpreting how agricultural-residue biochars modulate biofilm interfaces and redox-related metabolic signatures to improve triclocarban removal, providing guidance for designing biochar-supported bioprocesses for halogenated micropollutants. Full article

Straw compost products are considered an excellent organic amendment for acidic soils, yet their effectiveness and microbial associations remain poorly understood. This study employed a pot experiment to evaluate the effects of straw compost products from six crops (corn, soybean, wheat, rice, peanut, and canola) on corn growth and nutrient uptake, soil physicochemical properties, and microbial community in an acidic red soil and examined how microbial community changes relate to plant performance. The results showed that straw compost products significantly enhanced corn growth and contents of nitrogen, phosphorus, and potassium in the aboveground tissues, except for wheat and canola straw. Compost products also improved availability of soil nutrients to varying degrees and affected the bacterial community structures in bulk and rhizosphere soils. There were significant differences in the improvement effects among straw types, with leguminous crops being better than cereal crops. Corn growth was closely correlated with increased soil organic carbon. The influence of the rhizosphere on bacterial communities was stronger than that of straw compost type. The dominant phyla Actinobacteriota and Patescibacteria were key bacterial groups positively associated with corn nutrient uptake in the rhizosphere. Compared to the bulk network, the rhizosphere microbial co-occurrence network exhibited higher modularity and a greater proportion of positive edges, suggesting a more cooperative interaction pattern. The influence of compost products might be associated with distinct nitrogen and phosphorus transformation pathways. Overall, this study clarifies the differential effects of straw compost products on acidic soil improvement and reveals strong associations between rhizosphere microorganisms and crop nutrient uptake. Full article

Aerobic composting shows state-dependent dynamics in key parameters such as temperature, moisture content, oxygen concentration, and pH, and these variables are strongly coupled over time. This coupling makes accurate state identification and process regulation challenging when relying on single-parameter thresholds or experience-based control. To enable robust recognition of composting states throughout the process, we propose an IRRTO-optimized CNN–LSTM–attention model (IRRTO–CNN–LSTM–attention). The model uses a convolutional neural network (CNN) to extract discriminative multivariate features, a long short-term memory (LSTM) network to model temporal dependencies, and an attention module to adaptively emphasize informative features. To address the hyperparameter selection challenge, the Rapidly-exploring Random Tree Optimizer (RRTO) was introduced and further enhanced via four strategies (fluctuating attenuation adaptive regulation, dual-mode guided update, dynamic dimension adaptive perturbation, and dual-mechanism adaptive perturbation regulation), forming the improved IRRTO. The proposed approach was validated using sensor data from windrow composting of pig manure and corn straw. The IRRTO–CNN–LSTM–attention model achieved an overall accuracy of 98.31% in classifying the four states (mesophilic/heating, thermophilic, cooling, and abnormal) on the independent test set, which was 3.39 percentage points higher than the RRTO-based model. These results suggest that the proposed method can accurately identify composting states and support early warning and state-specific regulation in practical aerobic composting systems. Full article

Moisture content varies continuously during aerobic composting, which changes material flowability and can limit the use of a single set of discrete element method (DEM) parameters. To address this issue for a multi-component corn straw–pig manure mixture, we developed a rapid calibration workflow covering a moisture content range of 29–80%. Angle of repose (AoR) images were obtained using a cylinder-lifting test. To improve robustness for irregular pile contours, we proposed an AoR extraction method that combines LOESS smoothing with least-squares line fitting. Key DEM contact parameters affecting AoR were screened using a Plackett–Burman design, and their effective ranges were refined using a steepest-ascent test. A Box–Behnken design was then used to establish a response surface linking AoR to the significant DEM parameters. In addition, a polynomial relationship between moisture content and AoR was fitted and coupled with the AoR-parameter response surface to predict key DEM parameters directly from moisture content. Validation results showed that the predicted AoR exhibited a relative error below 10% across the tested moisture contents. An independent baffle-lifting validation test yielded a relative error below 5%. Overall, this workflow provided a practical strategy for setting DEM simulations of composting feedstocks under variable moisture content and supports numerical analysis and structural optimization of composting-related machinery. Full article

The structural stability of lignocellulosic fibers in crop straw presents a significant challenge to its short-term biodegradation in natural environments, particularly in the cold regions of northern China. To isolate low-temperature straw-degrading bacteria, we selectively enriched microorganisms from straw-amended soils using lignocellulose as the sole carbon source. Three strains were isolated and identified: Stenotrophomonas sp. X24, Flavobacterium sp. X26, and Erwiniaceae bacterium X27. These strains were capable of growth and maize straw degradation within a 4–20 °C range and exhibited key cellulolytic activities (CMCase, FPase, and β-glucosidase). A synthetic three-strain mixture was assembled by combining these isolates in equal proportions. Solid-state fermentation (12 °C, 45 days) was used to assess straw degradation efficacy, while separate enzyme production experiments (12 °C, 3 days) were conducted to evaluate key cellulolytic activities and subsequently optimize culture conditions. The three-strain mixture achieved a net straw degradation rate of 30.93 ± 1.05%. Furthermore, optimization of culture conditions enhanced the carboxymethyl cellulase activity (CMCase) to a maximum of 24.51 ± 0.97 U/mL. The study demonstrates that the three-strain synthetic microbial mixture effectively degrades straw at low temperatures, offering a promising microbial resource to improve straw utilization and soil fertility in cold regions. Full article

This study aimed to evaluate the effects of modified corn straw dietary fiber (MCDF) on growth performance, nutrient metabolism, serum biochemistry, antioxidant capacity, intestinal morphology and hepatic lipid deposition in broilers. A total of 200 one-day-old Arbor Acres broilers were randomly allotted to four groups: the control group was fed basal diet, while three treatment groups supplemented with MCDF at 0.5%, 1%, and 1.5% of the basal diet, respectively. The results revealed that MCDF reduced ADG (p = 0.008) and increased feed/gain (p = 0.028) in the early stage, with no significant effects on ADG and feed/gain in the later or overall rearing periods (p > 0.05). In the early stage, 1% and 1.5% MCDF reduced ether extract metabolizability (p = 0.001), and 0.5–1.5% MCDF reduced phosphorus metabolizability (p < 0.001). Compared to the control group, 0.5–1.5% MCDF had no significant effects on nutrient metabolism in later stage and slaughter performance, but it reduced the 24 h pH of breast muscle and serum levels of LDL-C, HDL-C, TG, TC, and GLU (p < 0.05). The 1% MCDF decreased L* at 15 min and 24 h of leg muscle (p < 0.05). The 0.5% and 1% MCDF increased serum T-AOC levels and 1% MCDF increased CAT (p < 0.05), whereas 1.5% MCDF decreased SOD (p < 0.05). MCDF increased the villus height-to-crypt depth ratio by reducing crypt depth (p < 0.05) and improved the histomorphology of hepatocytes, accompanied by a reduction in the number of lipid droplets in the liver. Therefore, 0.5–1.5% MCDF can be recommended in broiler diets in the later stage, as it had no negative effects on growth performance, nutrient metabolism, and effectively reduced blood lipids and glucose levels, enhanced antioxidant capacity, and ameliorated hepatic vacuolar degeneration and lipid deposition. Full article

This study evaluated the effects of straw particle size (short or long) and corn physical form (ground or whole) in diets on growth performance, rumen fermentation and fecal score in calves. Sixty female newborn calves were randomly assigned to one of the four treatments: 90% pelleted starter and 10% short straw (PSS); 70% pelleted starter, 20% whole corn and 10% short straw (PWCSS); 90% pelleted starter and 10% long straw (PLS); 70% pelleted starter, 20% whole corn and 10% long straw (PWCLS). In PSS and PLS treatments, all of the corn was within the pelleted starter. Calves were weaned at 68 days of age. Body weight (BW), wither height and heart girth were measured at 3 and 68 days of age. Feed intakes and fecal scores were measured daily. Rumen fluid and blood samples were collected for rumen pH, rumen volatile fatty acid (VFA) and blood β-hydroxy butyrate (BHB) measurements at 68 days of age. Weaning BW, average daily weight gain (ADG) and weaning wither height were significantly lower in PLS compared to other treatments. Weaning heart girth was significantly lower in PSS and PLS than PWCSS and PWCLS. Feed intake was significantly higher for PWCSS than PWCLS. PWCLS had a significantly lower feed efficiency (starter feed intake/ADG) than PLS. No significant differences were observed for ruminal pH, ruminal acetate and blood BHB among the treatments. In the diets including short straw, ruminal propionate, butyrate and total VFA concentrations were significantly higher for PWCSS than PSS. In the diets including long straw, the ruminal propionate concentration was significantly greater for PLS than PWCLS, and ruminal butyrate and total VFA concentrations were not different for PLS and PWCLS. This study indicated that the effect of corn physical form (ground or whole) on ruminal propionate, butyrate and total VFA concentrations could vary depending on straw particle size. Fecal score was significantly lower in PSS compared to other treatments. In conclusion, long straw combined with pelleted concentrate reduced growth performance in pre-weaning calves. Whole corn inclusion in the diets with long straw increased ADG and weaning BW and improved feed efficiency. Full article

Accurately quantifying the amount of corn straw returned to the field is crucial for evaluating conservation tillage measures and phaeozem protection. This study proposes a framework for quantitatively estimating the amount of corn straw returned to the field based on UAV multispectral imaging, integrating a standardized spectral correction strategy, a novel straw index (SI), and an improved deep learning model (convolutional neural network-straw, CNN-Straw). By combining multispectral images acquired by UAVs with ground-measured straw weight data, regression datasets covering autumn and spring conditions were constructed. The proposed straw index aims to enhance the spectral differences between non-photosynthetic straw residues and living vegetation. Furthermore, the CNN-Straw model, combining frequency domain convolution and local spatial attention mechanisms, has an improved ability to represent the complex texture of straw features. Experimental results show that CNN-Straw outperforms traditional machine learning models, including random forest (RF), support vector regression (SVR), and XGBoost, achieving a high coefficient of determination (R²) of 0.82 on different seasonal datasets and effectively reducing the root mean square error (RMSE) and mean absolute error (MAE). Cross-seasonal experiments further demonstrate the stable performance of the framework under different environmental conditions. The proposed method provides an efficient and scalable solution for the quantitative assessment of straw return to the field, supporting precision agricultural management and phaeozem conservation practices. Full article

Water seepage in saline soils can compromise the stability of landfill cover layers and cause ecological pollution. Biochar, recognized as a novel sustainable material for soil improvement, has garnered significant attention due to its large specific surface area and complex pore structure. Its addition can alter the physico-chemical properties of soil, including pore structure characteristics, compaction behavior, and liquid seepage paths. This study therefore focuses on saline soil, investigating the effects of biochar type and addition rate on the soil’s hydraulic conductivity through variable-head permeability tests. The correlation between changes in microscopic structural characteristics and hydraulic conductivity was analyzed using SEM and MIP techniques. The results indicate the following: (1) Both corn straw and wood biochar affect the hydraulic conductivity of the modified soil, with the degree of influence varying based on the presence and dosage of biochar, generally leading to a reduction. (2) The corn straw biochar-modified soil exhibited a more significant decrease in hydraulic conductivity—by approximately one order of magnitude—compared to wood biochar, reaching a minimum value of 1.04 × 10⁻⁶ cm/s at a 10% addition rate. (3) Analysis from SEM and MIP tests reveals that incorporating biochar alters the original pore structure of the soil, causing macropores to transition towards mesopores and micropores, and resulting in the narrowing or clogging of pore channels, which ultimately reduces the hydraulic conductivity. The finding that biochar amendment decreases hydraulic conductivity provides valuable data to support the design of landfill cover layer schemes. Full article

This article presents a prospective analysis of the corn agro-industrial chain in Colombia up until 2035, using a mixed-methods approach that integrates technological surveillance, two rounds of the Delphi method, S-curve analysis, and patent–publication matrices and quadrants. Text-mining analysis was conducted using VantagePoint^® v15.1 software, enabling the generation of multiple analytical outputs, including cluster maps, co-occurrence networks, and relational matrices. The study examines the dynamics of scientific and technological production related to the utilization of corn by-products and residues over the period 2003–2025. A total of 30 Delphi responses were collected from experts representing academia, industry, and government institutions in Argentina, Ecuador, Portugal, and Colombia. Based on expert consensus, the Delphi process identified 23 priority topics and 40 additional topics for discussion. Six priority themes were highlighted: (i) antioxidant and antimicrobial packaging derived from bioactive compounds extracted from corn by-products; (ii) bioethanol production; (iii) biodegradable straw manufactured from basket fibers; (iv) bioactive extracts for application in anti-aging cosmetic formulations; (v) modified biochar for the adsorption of ammonium and phosphate ions from aqueous systems; and (vi) the use of corn stover to enhance soil nitrogen content and grain yield. Finally, patent-based S-curve analysis and patent–publication matrices revealed notable asymmetries between scientific knowledge production and patenting activity, underscoring structural gaps in the translation of research into technological innovation within the corn agro-industrial sector. Full article