Search Results (211)

Houses constructed using straw bales have typically been built from wheat, rice, or barley straw, depending on local availability. Miscanthus is a perennial biomass crop with a high lignocellulose content that is grown on agriculturally marginal land. We describe the construction and as-built performance of what we believe to be the world’s first Miscanthus straw bale building. We describe the practical differences in working with the material that arise due to the slightly different physical properties of the baled material. The moisture content of the walls 17 months after construction was 11.3 ± 0.5% (pre-construction 10.72 ± 0.4% n.s.d). The in situ U value of the wall was 0.162 W/m²K, which compares to a reported U value of 0.189 W/m²K in wheat straw bale buildings of comparable wall thickness. Given the greater resistance of Miscanthus to biodegradation than wheat straw, its wider use as a construction material should be considered. Full article

Combining straw return with nitrogen fertilizer application is an effective strategy to enhance farmland productivity, improve soil structure, and mitigate climate change. Although straw return practices are widely recommended in agricultural ecosystems targeting sustainable agriculture, few studies have investigated the combined effects of consecutive years of straw return and nitrogen-fertilizer interactions on rice yield, nitrogen use, and lodging resistance, as well as the potential interactions among these variables. To investigate the effects of consecutive years of rice straw return and nitrogen fertilizer inputs on rice growth, a straw return experiment was conducted in 2021–2022 in Northeast China. The test crop was rice (cv. Jinongda No. 667), with four nitrogen fertilizer levels: 0 kg/ha (N0), 125 kg/ha (N1), 150 kg/ha (N2), and 175 kg/ha (N3). Five straw-return treatments were applied: no straw (S0), straw return to the field for one year (S1), continuous straw return to the field for two years (S2), continuous straw return to the field for three years (S3), and continuous straw return to the field for four years (S4). Results indicated that under the same straw return year, the N3 yield, nitrogen accumulation, nitrogen use efficiency, and apparent utilization were the highest. Under the same nitrogen treatment condition, S1 significantly reduced yield, nitrogen accumulation, nitrogen use efficiency, apparent nitrogen utilization, and lodging index compared to S0. However, under N3 conditions, S3 did not significantly differ from S0. Both S3 and N3 enhanced nitrogen uptake, translocation, and accumulation in rice. Their significant interactive effect increased yield while simultaneously enhancing the lodging resistance and stem strength. The study findings highlighted the effects of years of straw return and nitrogen fertilizer application on crop yield and resistance traits. They further demonstrated that the combination of straw return and optimized nitrogen fertilizer inputs could improve resource utilization and result in a high-yielding and efficient crop population. Full article

In this study, an analysis was carried out of the combustion of pellets made from chamomile and English ryegrass biomass, including those with the addition of kaolin and urea, in terms of their physical and chemical properties. During combustion tests with synchronized timing, the concentrations of CO₂, CO, NO, and SO₂ in the flue gases were measured, along with the temperatures of the supplied air and the flue gases. The addition of kaolin improved combustion parameters, reduced CO emissions, and stabilized the combustion process, despite the deterioration of the mechanical durability of the pellets. Combustion in the drop-in burner (type B tests) showed higher energy efficiency (CEI) and lower flue gas toxicity (TI) than in the grate system (type A tests). The SiO₂ content in the chamomile ash explained its higher resistance to slagging, confirmed by characteristic ash temperatures. Comparison with other biofuels (straw, hay, sawdust) showed similarities or advantages in terms of reducing CO, NO, and SO₂ emissions. NO emissions were lower for pellets with urea and kaolin added, although in the case of biomass with high nitrogen content these relationships require further improvement. The research results indicate the potential of herbaceous biomass as a fuel in local heating systems. However, modification of such fuels is also associated with the need for further research on reducing emissions during unstabilized combustion phases, with particular emphasis on the ignition phase. Full article

This study aims to quantify total VOC emissions and evaluate how torrefaction alters the heat of combustion of three agricultural residues. The work examines the amount of VOC emissions during the torrefaction process at various temperatures and investigates the changes in the heat of combustion of agri-biomass resulting from the torrefaction process. The process was carried out at the following temperatures: 225, 250, 275, and 300 °C. Total VOC emission factors were determined. The reaction kinetics analysis revealed that meadow hay exhibited the most stable thermal behavior with the lowest activation energy. At the same time, rye straw demonstrated higher thermal resistance and complex multi-step degradation characteristics. The authors analyze three types of agricultural biomass: meadow hay, rye straw, and oat straw. The research was divided into five stages: determination of moisture content in the sample, determination of ash content, thermogravimetric analysis, measurement of total VOC emissions from the biomass torrefaction process, and determination of the heat of combustion of the obtained torrefied biomass. Based on the research, it was found that torrefaction of biomass causes the emission of torgas containing VOC in the amount of 2–10 mg/g of torrefied biomass, which can be used energetically, e.g., to support the torrefaction process, and the torrefied biomass shows a higher value of the heat of combustion. Unlike prior studies focused on single feedstocks or limited temperature ranges, this work systematically compares three major crop residues across four torrefaction temperatures and directly couples VOC quantifications. Full article

Straw fiber curtain contains a plant fiber blanket woven from crop straw, which is mainly used to protect embankment slopes from rainwater erosion. To investigate the erosion control performance of slopes covered with straw fiber curtains of different structural configurations, physical model tests were conducted in a 95 cm × 65 cm × 50 cm (length × height × width) test box with a slope ratio of 1:1.5 under controlled artificial rainfall conditions (20 mm/h, 40 mm/h, and 60 mm/h). The study evaluated the runoff characteristics, sediment yield, and key hydrodynamic parameters of slopes under the coverage of different straw fiber curtain types. The results show that the A-type straw fiber curtain (woven with strips of straw fiber) has the best effect on water retention and sediment reduction, while the B-type straw fiber curtain (woven with thicker straw strips) with vertical straw fiber has a better effect regarding water retention and sediment reduction than the B-type transverse straw fiber curtain. The flow of rainwater on a slope covered with straw fiber curtain is mainly a laminar flow. Straw fiber curtain can promote the conversion of water flow from rapids to slow flow. The Darcy-Weisbach resistance coefficient of straw fiber curtain increases at different degrees with an increase in rainfall time. Full article

This study presents a cost-effective, carbon-negative construction material for affordable housing, developed entirely from locally available agricultural wastes: rice husk ash, wood ash, and rice straw—materials often problematic to dispose of in many African regions. Rice husk ash provides high amorphous silica, acting as a strong pozzolanic agent. Wood ash contributes calcium oxide and alkalis to serve as a reactive binder, while rice straw functions as a lightweight organic filler, enhancing thermal insulation and indoor climate comfort. These materials undergo natural pozzolanic reactions with water, eliminating the need for Portland cement—a major global source of anthropogenic CO₂ emissions (~900 kg CO₂/ton cement). This process is inherently carbon-negative, not only avoiding emissions from cement production but also capturing atmospheric CO₂ during lime carbonation in the hardening phase. Field trials in Kenya confirmed the composite’s sufficient structural strength for low-cost housing, with added benefits including termite resistance and suitability for unskilled laborers. In a collaboration between the University of Tartu and Kenyatta University, a semi-automatic mixing and casting system was developed, enabling fast, low-labor construction of full-scale houses. This innovation aligns with Kenya’s Big Four development agenda and supports sustainable rural development, post-disaster reconstruction, and climate mitigation through scalable, eco-friendly building solutions. Full article

In this study, Bacillus amyloliquefaciens SQ-2, previously isolated from a commercial watercress paste, was investigated for its potential in promoting rice growth in Pb/Al-contaminated acidic soil, especially when used in conjunction with corn straw biochar. Firstly, the physiological properties of rice were enhanced, with the activities of catalase and superoxide dismutase increasing by 162.5% and 162.9%, respectively. Additionally, the total phenolic and chlorophyll contents of rice increased by 17.6% and 83.7%, respectively. Secondly, the nutrient content of the rice rhizosphere soil was improved. In particular, nitrate nitrogen, available potassium, and sucrase were enhanced by 9.4%, 45.9%, and 466.8%, respectively. Moreover, SQ-2–biochar was demonstrated to have a notable capacity for removing Pb²⁺ and Al³⁺. The mineralization of Pb²⁺ and Al³⁺ was achieved through the use of SQ-2–biochar, as revealed by SEM-EDS, XRD, XPS, and FT-IR analyses, with the main precipitates being Pb₃(PO₄)₂ and AlPO₄. Functional groups such as C-O-C, C=O, N-H, P-O, and -O-H on the microbial surface were found to be involved in the biosorption process of Pb²⁺ and Al³⁺. In summary, SQ-2–biochar can effectively mineralize Pb²⁺ and Al³⁺, enhance the physiological properties of rice, and improve soil nutrients, thereby augmenting the antioxidant capacity, photosynthesis, and stress resistance of rice and ultimately promoting rice growth. Full article

The agricultural sector faces growing pressure to enhance productivity and sustainability, prompting innovation in machinery design. Traditional materials such as steel still dominate but are a cause of increased weight, soil compaction, increased fuel consumption, and corrosion. Composite materials—and, more specifically, fiber-reinforced polymers (FRPs)—offer appealing alternatives due to their high specific strength and stiffness, corrosion resistance, and design flexibility. Meanwhile, increasing environmental awareness has triggered interest in biocomposites, which contain natural fibers (e.g., flax, hemp, straw) and/or bio-based resins (e.g., PLA, biopolyesters), aligned with circular economy principles. This review offers a comprehensive overview of synthetic composites and biocomposites for agricultural machinery and equipment (AME). It briefly presents their fundamental constituents—fibers, matrices, and fillers—and recapitulates relevant mechanical and environmental properties. Key manufacturing processes such as hand lay-up, compression molding, resin transfer molding (RTM), pultrusion, and injection molding are discussed in terms of their applicability, benefits, and limits for the manufacture of AME. Current applications in tractors, sprayers, harvesters, and planters are covered in the article, with advantages such as lightweighting, corrosion resistance, flexibility and sustainability. Challenges are also reviewed, including the cost, repairability of damage, and end-of-life (EoL) issues for composites and the moisture sensitivity, performance variation, and standardization for biocomposites. Finally, principal research needs are outlined, including material development, long-term performance testing, sustainable and scalable production, recycling, and the development of industry-specific standards. This synthesis is a practical guide for researchers, engineers, and manufacturers who want to introduce innovative material solutions for more efficient, longer lasting, and more sustainable agricultural machinery. Full article

Freeze–thaw (F/T) technology is an environmentally friendly and efficient method for residual sludge treatment. This study investigates the enhancement of sludge dewatering performance through the addition of straw during F/T cycles. A mathematical model was established using the Box–Behnken central composite design and validated via COMSOL Multiphysics simulations. The optimal conditions were identified as freezing at −16 °C for 24 h, with 12.5 freeze–thaw cycles and a straw mixing ratio of 20%, reducing the sludge moisture content from 62.7% to 35.9%. The specific resistance to filtration (SRF) and cake moisture content decreased significantly with increasing straw addition, reaching a minimum SRF of 1.30 × 10¹² m/kg at the optimal straw ratio. Straw conditioning also intensified the combustion stage of the sludge by increasing the maximum weight loss rate and elevating the thermal decomposition temperature. Numerical simulations confirmed the experimental results, demonstrating that straw addition significantly improves sludge dewaterability by modifying heat and mass transfer mechanisms. Full article

Human agricultural activities can impact the soil microbial ecosystem, but the future implications of such changes remain largely unknown. This study aimed to explore how soil microbes survive and reproduce under the pressure of human agricultural cultivation and whether they resist or adapt. A 10-year continuous experiment was conducted, planting a maize and soybean rotation (control group), alfalfa (legume), and wheat (poaceae) to study the impact of different crop planting on soil microbial communities. During the experiment, the physical and chemical properties of the soil samples were measured, and the rhizosphere microbial communities were analyzed. Different crop plantings had varying effects on soil microbial species diversity, but these differences were relatively limited. The relative abundance of Cyanobacteriales (order) was higher in wheat than in alfalfa. Moreover, Cyanobacteriales were positively correlated with soil peroxidase, thereby promoting wheat growth. In addition, nutrition for fungi is mainly derived from decaying straw and plant roots. This study divided soil microbes under agricultural cultivation conditions into three categories: adaptive microbes, neutral microbes, and resistant microbes. At the ecological level of plant rhizosphere microbes, the plant rhizosphere soil microbial community showed a coevolutionary relationship with human cultivation activities. Future research needs to pay more attention to the adaptability of soil microbial communities to agricultural cultivation and the potential impact of this adaptability on the global ecosystem. Full article

Alkali-activated-slag cementitious material (AASCM) is distinguished by minimal energy consumption, reduced pollution, and superior mechanical properties; however, it is prone to issues such as susceptibility to cracking and inadequate frost resistance. To facilitate its application in cold region construction, research on AASCM modifications was conducted following freeze-thaw cycle and chloride ion corrosion coupling tests. The test results show that the AASCM made of recycled rubber and coal ash does not change much in shape or appearance after 100 freeze-thaw cycles, with a mass loss rate of less than 5% and a compressive strength loss rate of less than 25%. Furthermore, the AASCM containing recycled rubber, coal ash, and straw fiber demonstrates an effective resistance to freeze-thaw and chloride ion coupling, maintaining its appearance and shape without notable changes and exhibiting a mass loss rate of less than 25% following 100 such tests. Following 100 tests for freeze-thaw and chloride ion coupling, the appearance and morphology of AASCM exhibited no significant alterations, with a mass loss rate below 5% and a compressive strength loss rate under 25%; microscopic analysis revealed that the C-A-S-H gel maintained a relatively dense and stable structure. Adding recycled rubber to the AASCM matrix can slow the spread of cracks, make the material more flexible, and make it more resistant to frost. Straw fibers can stop cracks from getting bigger, and adding coal ash helps make more C-A-S-H gel, which improves the AASCM’s mechanical properties. Full article

The pyrolysis of sewage sludge into biochar, enhanced by incorporating agriculture waste rich in inorganic minerals and lignocellulosic compounds, provides an effective approach for achieving sludge-harmless treatment and resourceful utilization. In this study, sewage sludge and maize straw-based biochar (SMB) was prepared using the co-pyrolysis method, and the effects of different application ratios (0%, 1%, 3%, and 5%, w/w) of SMB on soil properties, ryegrass growth, microbial community structure, and Pb content and speciation in the contaminated soil of constructed wetlands were investigated. The results showed that SMB had a high carbon content (28.58%) and was rich in functional groups (e.g., -C-O, -C-N). The results indicated that increasing SMB dosage (0–5% w/w) in Pb-contaminated soil elevated soil pH from 6.40 to 7.93, cation-exchange capacity (CEC) from 30.59 to 79.03 cmol/kg (+158%), and organic carbon content by 65% (from 176.79 mg/kg to 107.3 mg/kg), while reducing available phosphorus and potassium by 20% and 30%, respectively, resulting in a 6% decline in ryegrass leaf length. SMB application enriched Pb-resistant bacteria (e.g., Sphingomonas abundance increased from 10.3% to 11.2%) and enhanced Pb immobilization. After 55 days, the total soil Pb increased by 33%, and the residual fraction Pb significantly increased by 7.3% to 21.7%, driven by functional group complexation, ion exchange, pH, and CEC improvements. Full article

Polylactic acid (PLA) is widely used in 3D printing for its biodegradability and ease of processing, but its brittleness and low impact strength often restrict its suitability for more demanding applications. The novelty of this work lies in its direct comparative approach: we systematically reinforce PLA with two distinct agricultural residues—rice husk and rice straw—under identical conditions to clarify how particle size (100 vs. 200 mesh) and NaOH surface treatment affect mechanical performance. Composite filaments containing 5–20 wt% of each fiber were produced and 3D-printed into standard tensile and flexural specimens. The results show that, although tensile strength declines at higher fiber loadings, tensile modulus, flexural strength, and impact resistance can improve significantly—particularly with 200-mesh and NaOH-treated fibers. Fourier transform infrared (FTIR) spectroscopy confirms partial lignin removal and enhanced cellulose exposure, improving fiber–matrix adhesion, which is corroborated by scanning electron microscopy (SEM) observations of reduced voids. This comparative study demonstrates that surface-treated, finely milled rice husk and rice straw significantly enhance PLA’s stiffness and toughness, offering a sustainable alternative to conventional polymeric additives. The insights gained here on fiber content, chemical treatment, and 3D printing parameters can guide the broader industrial adoption of these natural fiber-reinforced PLA composites, particularly in automotive and construction applications that require lightweight, durable materials. Full article

To address the issues of large turning radius, low mechanical compression bale density, and high requirements for knotters in existing towed straw balers, a self-propelled straw-harvesting and -baling machine has been developed. The machine can perform multiple tasks in one pass, including the harvesting, chopping, dust removal, compression bale, and net-wrapping of corn straws. By utilizing a hydraulic closed-compression system, the straw naturally binds together and is wrapped in netting, eliminating the need for knotters, thereby reducing operational costs and increasing bale density. This study focused on designing a baling compression and net-wrapping device, calculating the parameters of the compression hydraulic cylinder and hydraulic system, designing the control system, and conducting field tests. The results show that the finisher baling rate reached 99%, the regular bale rate reached 100%, the bale density was 264.77 kg/m³, the bale drop resistance rate was 94%, and the pure working hour productivity was 4.03 t/h. This research provides a reference for the design of straw-harvesting balers. Full article

Peanut yield and quality are often threatened by soil degradation under continuous cropping. Biochar has been known to improve the soil microbial community and plant resistance. However, studies on its functions to reduce soil degradation losses and improve the peanut yield are limited. A field peanut experiment was conducted in an Alfisol soil and biochar was applied at a rate of 20 t ha⁻¹ in 2022. The biochar was prepared from woodchip (WB) and maize straw (MB) feedstocks alone, as well as with co-composted biochar of the same feedstocks with pig manure labeled as WBSC and MBSC amendment, respectively. The conventional organic manure was applied as a control treatment (OM). All plots were base-fertilized with a mineral compound fertilizer of N-P₂O₅-K₂O (16-16-16, %) at 600 kg ha⁻¹. Topsoil (20 cm) and plant samples were collected at the time of peanut harvest. Soil quality, enzyme function, peanut growth traits, microbial abundance, and community composition were analyzed. Compared to OM, peanut yields increased by 22%, 23%, and 18% under WB, WBSC, and MBSC, respectively. The content of oleic acid increased by 4–5%, while the content of linoleic acid decreased by 7–9%, respectively, under biochar–compost treatments. However, biochar amendment alone showed non-significant changes in these fatty acids. The soil extracellular enzyme activity increased by 3.7–5.5% with biochar amendments and 6.4–10.1% with biochar–compost application. The enzyme activity ratio of hydrolase to non-hydrolase, of C cycling to N cycling, and of P cycling increased by 11.4–15.9%, 20.9–33.8%, and 14.7–23.5% under biochar amendments and by 20.5–25.0%, 17.4–39.0%, and 23.5–32.3% under biochar–compost, respectively. Overall, crop residue biochar enhanced peanut yield and quality by improving soil aggregation, enzyme functionality, and fungal community in line with the soil nutrient supply. Full article