Reduced Bulk Density Research Articles

Advances in SiC-reinforced cementitious composites for aerostatic thrust bearings based on full factorial design

Aerostatic thrust bearings utilise air as a lubricant to support loads while minimising friction and wear. The airflow within these bearings is controlled by a restrictor, which can be constructed from various materials, including porous substances. The selection of a porous material for the restrictor is particularly influenced by factors such as permeability, stiffness, and homogeneity. This work proposes a microstructural design for air restrictors based on compacted cementitious composites. A novel cementitious composite, consisting of silicon carbide (SiC) particles and Portland cement, is fabricated through cold pressing at 10 MPa and a low water-to-cement ratio of 0.30. To evaluate the effects of SiC particle size and weight fraction on the physical and mechanical properties of the composites, a statistical design approach is employed. The response variables include apparent density, apparent porosity, oxygen permeability coefficient, compressive strength, flexural strength, and dynamic modulus. In general, a significant reduction in density, compressive strength, flexural strength, and dynamic modulus, along with an increase in porosity and oxygen permeability, is achieved by composites made with smaller SiC particles. A higher weight fraction of SiC reduces bulk density and compressive strength, while increasing porosity and oxygen permeability. Finally, composites made with 67 wt% of fine SiC particles exhibit promising characteristics for aerostatic bearings, particularly in terms of porosity and permeability.

Phosphogypsum improves soil and benefits crop growth: An effective measure for utilizing solid waste resources

The utilization rate of phosphogypsum (PG) is currently low, and prolonged storage poses environmental pollution. Therefore, there is an urgent need to promote resource-efficient utilization. This study investigated the alterations in the characteristics of modified PG artificial soil (MPG-soil) and their influence on buckwheat (Fagopyrum esculentum Moench) growth using hierarchical land reclamation technique (HLRT) and integrated land reclamation technique (ILRT). The results demonstrated that MPG-soil reduced bulk density (3.8–6.9%), enhanced moisture content (up to 22%), and improved enzymatic activity. HLRT achieved superior phosphorus mineralization (7.53 U/g S-NP activity) and increased buckwheat yield by 130.6% over controls. Despite elevated soil salinity, MPG amendments restricted heavy metal accumulation in grains (BCF < 0.3), though Pb levels exceeded national standards due to background contamination. Nutrient dynamics revealed increased phosphorus availability but reduced organic matter, necessitating supplemental fertilization. The Nemerow index confirmed all treatments as “Safe and Clean”, while principal component analysis highlighted HLRT’s efficacy in balancing soil structure and fertility. Proline accumulation in high-PG treatments indicated adaptive stress responses. MPG-soil effectively contained heavy metal migration, ensuring agricultural product safety. This study assessed the potential of PG for land reclamation, and provided guidelines for its safe utilization in agriculture.

Application of unsegregated municipal solid waste char produced at low temperature and vermicompost for remediation of coal mine tailing soil.

The melioration of mine tailing soil (MTS) with unsegregated municipal solid waste (MSW) char and vermicompost (VC) significantly improved soil properties. The novelty of this research lies in utilizing MSW char derived directly from landfill waste, combined with VC, to enhance soil properties while mitigating heavy metal toxicity. Results indicate that 10% MSW char increased soil pH by 45.44% and specific gravity by 4%, while a 5% char and 30% VC mix improved volatile solids, electrical conductivity, water holding capacity, and total Kjeldahl nitrogen by 2.45, 1.76, 2.96, and 2.79fold, respectively, with a 3.3% reduction in bulk density. Heavy metal immobilization was significant, with total Fe, Ni, and Pb reducing by 28%, 22%, and 9%, respectively. Bioavailable Fe decreased by 89% with 20% char, while Ni and Pb bioavailability dropped to undetectable levels. Metal leachability was minimized, reducing Ni and Pb by 30% and 61%, respectively. These findings highlight the effectiveness of MSW char and VC in improving MTS properties, enhancing nutrient retention, and mitigating heavy metal risks, offering a sustainable approach for mine land restoration.

Changes in Soil Properties Under the Influence of Microplastics in Plastic and Open Field Production in Three Serbian Valleys

Crop production in plastic greenhouses is one of the major sources of plastic pollution worldwide. The main hypothesis of this study is that the regular use of mulch film in greenhouses leads to the cumulative accumulation of microplastic particles (MPs) in the soil, which ultimately leads to changes in the soil properties. Therefore, the main objective of this study was to identify the possible changes in the physical, chemical, and biological properties of soil in greenhouses in three regions of Serbia. The following chemical parameters were determined: electrical conductivity, soil acidity, cation exchange capacity (CEC), total carbon (TC) and nitrogen (TN) content, plant-available phosphorus and potassium content, and trace element content. The following physical parameters were determined: particle size distribution, volumetric mass, specific mass, and porosity; the biological parameters that were determined were microbial respiration and labile carbon. The obtained data were processed using network analysis (NA) to identify the complex relationships between MP content and soil parameters. The NA results support the main findings that the presence of microplastics leads to the destruction of soil structure, which reduces bulk density and increases soil porosity. A strong positive correlation of MPs with soil particles &lt; 0.02 mm and a negative correlation with CEC were found. In the Danube Valley, soil respiration was 78% higher in the open ground compared to a plastic greenhouse. The results contribute to a better understanding of the influence of MPs on soil properties and its ecological functions.

Effect of Negative Substrate Bias Voltage and Pressure on the Structure and Properties of Tungsten Films Deposited by Magnetron Sputtering Technique

This paper investigates how negative substrate bias voltage and sputtering pressure influence tungsten coatings deposited via radiofrequency magnetron sputtering. Increasing the absolute value of negative bias voltage (up to −150 V) of the substrate results in higher mass density, higher surface roughness, better crystallinity, improved adhesion, and lower electrical resistivity. Raising the sputtering pressure (from 1 to 5 Pa) causes a reduction in bulk density, a decrease in crystallinity, increased electrical resistivity, lower conductivity, and weaker adhesion. These findings highlight the importance of carefully optimizing negative substrate bias voltage and sputtering pressure to tailor the microstructural, mechanical, and electrical properties of tungsten coatings to specific applications.

Soil physico-chemical properties, growth, root yield and qualities of two varieties of carrot (Daucus carota L.) as affected by organic and inorganic fertilizers

Soils with low concentration of heavy metals are necessary for production, and this is accomplished by combining soils with biochar and other organic matter which effectively enhance soil physico-chemical properties and yield. The study was conducted to evaluate the effectiveness of biochar, chicken manure and NPK 15-15-15 on soil physical and chemical characteristics, growth and root yield and qualities of two varieties of carrot. Vanessa F1 and Kuroda carrot varieties were planted in the forest Ochrosol-Oxisol soil in 2022 and 2023 cropping seasons in the Western Region of Ghana, Samreboi to investigate the influence of organic and inorganic soil amendments on the improvements of soil physical and chemical properties, growth, and yield of carrot. The treatments included sole chicken manure at a rate of 20 t/ha, sole biochar (20 t/ha), only NPK (300 kg/ha), and integrated amendments of NPK and biochar (150 kg/ha + 10 t/ha), NPK and chicken manure (150 kg NPK/ha + 10 t/ha CM) and the control. Application of biochar, chicken manure, their mixture with NPK fertilizer, and NPK fertilizer alone all significantly (p < 0.05) improved soil physical qualities. In both seasons, the altered plots outperformed the control in terms of root yield and yield components as well as root quality of carrots. Vanessa F1 variety grown with 300 kg NPK/ha produced the maximum root yield of 6.63 kg/ha in the 2022 season, while in the 2023 season, the sole chicken manure plot (20 t/ha CM) outperformed the rest of the amendments in root yield, recording 7.70 kg/ha in Vanessa F1 variety. The study found that applying chicken manure, biochar, and their combination with NPK fertilizer improved soil quality, enhancing moisture content and porosity, while reducing bulk density. Vanessa F1 consistently outyielded Kuroda. Farmers are, therefore, recommended to grow Vanessa F1 with NPK fertilizer, biochar and chicken manure to improve carrot root yield, root quality and soil characteristics.

Evaluating the Impact of Nano-Silica and Silica Hydrogel Amendments on Soil Water Retention and Crop Yield in Rice and Clover Under Variable Irrigation Conditions

The use of water-efficient soil amendments has gained increasing importance in agriculture, particularly in regions facing water scarcity. So, this study evaluates the impact of silica and nano-silica hydrogels on soil water retention, crop yield, and crop water productivity under variable irrigation regimes. Using a randomized complete block design with furrow irrigation, the experiment tested different hydrogel application rates and irrigation levels in rice (Oryza sativa L.) and clover (Trifolium alexandrinum L.) across two growing seasons. Statistical tests, including ANOVA and t-tests, confirm that nano-silica hydrogel significantly improves soil properties, yield, and crop water productivity (CWP), especially at moderate irrigation levels (70–90% of water requirements). In the first season, nano-silica hydrogel enhanced rice yield, with a maximum yield of 10.76 tons ha−1 with 90% irrigation and 119 kg ha−1 of hydrogel compared with other treatments. In the second season, clover yields were also positively affected, with the highest fresh forage yield of 5.02 tons ha−1 with 90% irrigation and 119 kg ha−1 nano-silica hydrogel. Despite seasonal variation, nano-silica hydrogel consistently outperformed silica hydrogel in terms of improving soil water retention, reducing bulk density, and enhancing hydraulic conductivity across different irrigation levels. Principal Component Analysis (PCA) revealed that nano-silica hydrogel significantly improved soil water retention properties, including the water-holding capacity (WHC), field capacity (FC), and available water (AW), and reduced the wilting point (WP). These improvements, in turn, led to increased crop yield and water productivity, particularly at moderate irrigation levels (70–90% of the crop’s total water requirements. These findings highlight the potential of nano-silica hydrogel as an effective amendment for improving soil water retention, enhancing crop productivity, and increasing crop water productivity under reduced irrigation conditions.

Evaluation of Physicochemical Parameters in Sandy Soils After Applying Biochar as an Organic Amendment

Sandy soils are not suitable for agriculture because they do not retain nutrients, and water drains quickly. The biochar applied to these soils provides nutrients, improves their fertility, and favors crop yields. Thus, this work aimed to evaluate the effect of the application of pine biochar and the pruning of green areas obtained by slow pyrolysis on the physicochemical attributes of sandy soil. For this purpose, a greenhouse experiment was conducted in fifteen pots randomly divided into three groups (five replicas) of treatment depending on the dose of biochar: 0% (0 g/pot, T1 control treatment), 10% (100 g/pot, T2), and 25% (250 g/pot, T3) calculated according to the volume of the soil. Likewise, 05 seeds of turnip (Brassica rapa subsp. rapa) were placed in each pot, where their germination and growth were monitored. Application of biochar reported an increase in organic matter, porosity, pH, electrical conductivity, cation exchange capacity, NO3-, K, and Mg (without significant differences) and a reduction in bulk density, P, and Ca (without significant differences). These behaviors were higher in T3, followed by T2, compared to T1. Similarly, T3 (68%, 7.5 ± 0.9 cm) showed a higher number of turnip germinations and growth compared to T2 (48%, 7 ± 0.6 cm) and T1 (28% 6 ± 0.4 cm). The biochar applied improved the attributes of the sandy soil, strengthening it against possible erosion and promoting the preservation of terrestrial ecosystems.

The Effect of Runnels on Salt Marsh Sediment Dynamics, Vegetation, and Nitrogen Cycling

Runnels, a climate adaptation technique that drains surface water to restore marsh vegetation and habitat, are increasingly being used to prevent the formation of shallow water impoundments or pannes in salt marshes that result in the loss of important ecosystem services. However, we know little about the effect of runnels on salt marsh biogeochemistry. This study measured how sediment characteristics and rates of nitrogen cycle processes were altered by impounded water and vegetation loss, and whether runnels can restore these marsh attributes to reference conditions. Impounded areas were 52 ± 4% less vegetated than nearby intact marsh, with 11 ± 2% less organic matter and 24 ± 5% higher bulk density. Additionally, impoundments removed 32 ± 32 µmol N m−2 d−1 less than reference marsh areas via denitrification. At six of the 11 runneled sites, vegetation percent cover increased by 40 ± 5%, accompanied by a 7 ± 3% recovery of organic matter and a 9 ± 6% reduction of bulk density. At sites where vegetation recovered to within 70% of reference plots at a site, runneled plots removed 97 ± 31 µmol more N m−2 d−1 than impoundments, which was also 82 ± 31 µmol more N m−2 d−1 than reference areas. The driver of recovery is related to initial site conditions, including higher redox potentials and lower porewater salinities, compared with sites where revegetation was unsuccessful. The extent of runnel effectiveness and the recovery of vegetation, sediment characteristics, and nitrogen cycle processes was variable among runneled marshes, and the effectiveness of runnels may depend on initial site-specific characteristics and degree of initial degradation.

Evaluation of Farming System Modules for Improving Profitability of Small Farmers in Coastal Odisha, India

The study evaluated the profitability, sustainability and environmental impact of integrated farming system (IFS) modules, including cropping systems, horticulture, dairy, poultry and fishery in an area of 1.2 ha, in coastal Odisha, India. This research project was part of the sixth production cycle under the All India Coordinated Research Project on IFS and conducted at the Central Research Station, Odisha University of Agriculture and Technology, Bhubaneswar, during the 2022-23 agricultural year. The experiment integrated five major modules: cropping systems (0.32 ha), horticulture (0.31 ha), dairy (2 cross-bred cows), poultry (500 coloured chicken for meat) and fishery (0.40 ha). Productivity was assessed using rice equivalent yield (REY) and economic returns were calculated for each module. Sustainability was evaluated through sustainable yield indices and carbon footprint assessments, while soil quality parameters, such as bulk density, pH, organic carbon and available macronutrients, were monitored over six years. Dairy emerged as the most productive module, yielding the highest REY (15.14 t) and gross return (Rs.3,27,040). Horticulture recorded the highest net return (Rs.1,40,627) and benefit-cost ratio (3.61). The cost of production was mainly influenced by external inputs (52%), followed by labour (33%) and system-recycled inputs (15%). The system generated 399 man-days annually, with over half contributed by dairy. Environmental sustainability was achieved through agroforestry and compost application, making the model carbon-negative. Dairy was the largest greenhouse gas emitter, while horticulture and biomass contributed significantly to carbon sequestration. Over six years, soil quality improved, with reduced bulk density, increased water-holding capacity and enhanced organic carbon levels. Sustainable yield indices for four modules were above 0.6, with dairy showing the highest sustainability. Poultry performance required further improvement to enhance overall system sustainability. In conclusion, the integrated farming system enhanced overall productivity, profitability and environmental sustainability for smallholder farmers in coastal Odisha, showcasing its potential for resource optimization and resilience.

Computer simulation of microwave-assisted drying: Coupled influence of microwave power and pulse ratio on product and process characteristics.

Computer simulation of microwave-assisted drying: Coupled influence of microwave power and pulse ratio on product and process characteristics.

Forest fuel structure and loading along a gradient of gray-phase mountain pine beetle severity in Jasper National Park, Alberta, Canada

Wildland fire fuels within the gray-phase of mountain pine beetle ( Dendroctonus ponderosae Hopkins) outbreak (4–10 years post mortality) are treated as homogenous despite potential variability. To assess if proportion of mortality due to mountain pine beetle in gray-phase stands significantly affects fuel structure, composition, and loading, detailed fuel measurements were collected across a range of severity in Jasper National Park, Alberta, Canada, by coincidence 1–3 years before a major wildfire. These were categorized based on outbreak severity thresholds of Light (&lt;35%), Moderate (36%–65%), and Severe (&gt;65%) beetle-induced pine mortality defined as the proportion of killed trees within a stand. The canopy fuels of both mature and small tree cohorts were significantly reduced with increasing outbreak severity. Severely affected stands showed a 49% reduction in mature tree canopy bulk density from original loading but increased herbaceous vegetation. Moderately affected stands had higher coarse woody debris loading (mean = 3.21 kg m– 2; SE = 0.49 kg m–2). These severity ratings can be used to quantify canopy fuel loss and signal potential shifts to other surface fuel types, barring fire. This is one of the first studies to showcase variability within gray-phase outbreak fuels, despite their prevalence in western Canada, and discuss the potential influences on fire behaviour.

Cork and Compost as Mitigators of Soil Compaction from Trampling in Urban Green Areas: Effects on Plant Growth and Soil Functionality

Compacted soils in urban areas suffer from reduced porosity, impairing plant growth, water infiltration, and gas exchange, thus exacerbating other potential environmental issues. Amending soil with organic matter can reduce bulk density and increase permeability, thereby enhancing soil fertility and functionality. This study evaluated the effects of two organic soil amendments (i.e., chipped cork and municipal waste compost) on soil functionality and the physiology of Quercus ilex trees, following a soil compaction treatment. Five soil treatments were compared: control (no compaction and amendments), soil compaction without amendments, and compaction with amendments including cork, compost, or a combination of both. Soil and plant physiological responses were analyzed during the summer months, focusing on soil gas exchange, temperature, moisture, microbial respiration, enzymatic activity, leaf gas exchange, leaf chlorophyll fluorescence, chlorophyll content, and maximum daily trunk shrinkage. The results showed that amended soils exhibited increased soil gas exchanges, lower temperatures, and higher microbial activity than non-amended compacted soils, thereby reducing the detrimental effects of soil compaction on plant physiology. These findings suggested that incorporating organic amendments into urban soils, especially those subjected to frequent trampling, could make them more resistant/resilient to compaction, supporting healthier green spaces and more sustainable urban ecosystems.

On farm soil health assessment across seven sub‐tropical cover crop management systems

AbstractThe integration of cover cropping in conventional farming systems has shown positive impacts on soil health enhancement. In Florida, where concerns persist about low productivity in mineral soils and significant carbon loss from organic soils, farmers are increasingly adopting cover crops in their routines. This collaborative study aimed to evaluate the immediate effects of cover cropping, comprehend the connections between soil health indicators, and measure quality indices for both mineral and organic soils. Across Florida, we conducted a comprehensive on‐farm study, gathering 272 samples from both mineral and organic surface soils, which were treated with winter or summer cover cropping, rice cultivation, and fallow or flooded fallow. After analyzing 12 health indicators, we employed statistical methods such as mean comparison, non‐parametric correlation, and regression for both pre‐ and post‐cover cropping periods. A modified Comprehensive Assessment of Soil Health scoring system was utilized to assess the quality indices of both soil types. Notably, cover cropping enhanced cation exchange capacity (CEC) and soil protein (SP) in organic soil while preserving an unchanged active carbon (AC) pool. In mineral soils, such practices improved CEC, organic matter, maximum water holding capacity, SP, and total Kjeldahl nitrogen while reducing bulk density and AC. Following cover cropping, correlations among indicators became more pronounced, emphasizing the intricate relationships among soil properties and essential nutrients. Despite this alteration, the health indices did not change in both soils after cover cropping. The study's confined duration, limited to a single cover crop season, may account for the observed impact.

Engineering Soil Quality and Water Productivity Through Optimal Phosphogypsum Application Rates

Water scarcity and soil degradation pose challenges to sustainable agriculture. Phosphogypsum, a low-cost solid waste, shows potential as a soil amendment, but its impact on water saving and soil quality need further study. This research assessed the effects of phosphogypsum application rates (CK: no phosphogypsum, 0.075%, 0.15%, 0.3% and 0.6%) on soil infiltration, water retention, salinity, soil quality, crop yield and irrigation water productivity (IWP) to identify the optimal rate. Phosphogypsum application altered pore structure and water potential gradients, slowing wetting front migration, increasing infiltration duration (102 to 158 min), cumulative infiltration (17.37 to 27.44 cm) (p &lt; 0.05) and soil water content (18.25% to 24.33%) (p &lt; 0.05) as the rate increased from CK to 0.6%. It also enhanced water retention by enhancing soil aggregation and reducing evaporation.By promoting the formation and stabilization of soil aggregates, phosphogypsum application (CK to 0.6%) reduced bulk density from 1.20 g/cm3 to 1.12 g/cm3 (p &lt; 0.05), while porosity, available nitrogen and urease activity increased by 3.70%, 39.42% and 82.61%, respectively (p &lt; 0.05). These enhancements provided a strong foundation for improved crop performance. Specifically, phosphogypsum enhanced yield through three pathways: (1) improving soil physical properties, which influenced soil nutrients and then improved enzyme activities; (2) directly affecting soil nutrients, which impacted enzyme activities and increased yield; and (3) directly boosting enzyme activities, leading to increased yield. The comprehensive benefits of phosphogypsum initially increased and then decreased, with an optimal application rate of 0.45% determined through TOPSIS, a method that ranks alternatives based on their proximity to an ideal solution, considering factors including soil quality, crop yield and IWP. These findings confirm the feasibility of phosphogypsum as an effective resource to enhance water efficiency and soil quality, promoting sustainable agricultural practices.

Thermophysiological Comfort Behaviour of Cut Protective Workwear Consisting of Filament Twisted Multicomponent Hybrid Yarn

Current cut protective gear is subject to several difficulties, such as the use of heavy fabric, complicated donning processes, lack of comfort and limited movement. When selecting the most comfortable cut protective fabric, it is important to consider the end users' specific needs. The aim of this study was to enhance the comprehension and optimisation of protective apparel for superior occupational safety and protection by exploring the intricate link between material composition, yarn structure and comfort parameters. Various combinations of filament twisted core sheath yarn consisting of stainless-steel/glass with high-performance polyethylene and polyester wraps were used to fabricate thermo-physiological comfortable cut protective workwear fabric. Twelve cut protective fabrics with the same areal density (200 g/m2) were prepared with 6-end satin weave using filament twisted core sheath yarn of five distinct linear densities (98.4 tex, 73.8 tex, 59.1 tex, 49.2 tex and 39.4 tex). These fabric samples were used to evaluate thermophysiological characteristics, including air permeability, dry and evaporative heat resistance, thermal conductivity, moisture permeability, wettability and moisture wicking according to the established standard. The cut protection of each sample was also measured according to EN 13997. The cut protection and thermo-physiological comfort attributes of cut-resistant clothing are greatly influenced by the proportion of core material (stainless-steel/glass) and yarn structural parameters (linear density and twist direction), which was observed by analysing the results. An increased core material percentage (stainless-steel/glass) contributes to increased fabric thickness and reduced bulk density, which influences the thermophysiological comfort attributes of the developed cut protective workwear fabric. Fabric made from a higher proportion of core material (stainless-steel/glass) with a lower bulk density exhibited an acceptable cut protection level and performed better in terms of thermo-physiological comfort attributes.

Improving the properties of clay soils in foundations through compaction and the integration of fibres and cement

Clay soils present significant challenges in engineering applications, particularly in the design and construction of foundations, due to their susceptibility to swelling and shrinkage. This research investigates the enhancement of clay soils through the incorporation of fibres, compaction, and cement, based on a comprehensive series of tests conducted at the Public Works Laboratory in Adrar, southern Algeria. The tests adhered strictly to technical standards in soil mechanics, examining the physical, mechanical, and thermal properties of the clay soil. The results demonstrated that applying a compressive strength of 2.5 MPa and incorporating palm and glass fibres in proportions ranging from 0% to 0.3% reduced bulk density by 0.95% to 7%. The capillary water absorption rate increased by 10.61% to 12.63%, while compressive strength improved by 11.4% to 34.37%. Furthermore, thermal conductivity decreased by 0.71% to 11.9%. These findings provide valuable insights into the properties of clay soils and the observed improvements. It can be concluded that soil enhancement through various materials and fibres is viable and yields positive outcomes in geotechnical applications.

Effect of rice hull amendment in green roof substrates

The use of waste and locally available materials could improve the sustainability of green roofs. Therefore, a study was conducted to evaluate the potential of a rice hulls in the organic and inorganic portion of green roof substrates. Three substrate mixtures were prepared at the site by mixing locally available materials. The substrate mixtures were designated as RPZV (rice hulls 6:1; pumice and zeolite mixture 2:1; vermicompost 2:1 by volume), PZR (rice hulls 2:1; pumice and zeolite 8:1), and PZV (pumice and zeolite 8:1; vermicompost 2:1). Measurements were performed including plant growth index, chlorophyll fluorescence, biomass accumulation on native and exotic plant species. Increased amounts of rice hulls in the substrate mixture had a significant effect on reducing bulk density up to 24%, increasing organic matter content up to 67% and maximum water holding capacity (WHC) of the substrate, but also had the lowest volumetric moisture values in the field measurements due to increased porosity and permeability of the substrate. Adversely, substrate mixtures with higher rice hull content experienced greater temperature fluctuations during the study period, which have resulted in increased plant mortality and stress for certain plant species during the study. As the organic part of the substrate, rice hulls caused a decrease on the salinity of the substrate by about 28% and provided higher survival rates and lower stress levels for A.schoenoprasum, C.creticus, L.spectabilis, D.chinensis and Sedum species. The results of the study suggested that, rice hulls may have the potential to be used in appropriate proportions due to their low bulk density, low salinity and resistance to degradation, leading to a reduction in the environmental impact of green roof construction.

Incorporating Cattle Manure Improves Hydraulic Properties and Enhances Infiltration Rates of Low‐Infiltrability Saline‐Sodic Soils

ABSTRACTDrylands present a significant challenge to global agricultural production, especially in dryland saline‐sodic soils, which are marked by poor structure and low infiltrability. Enhancing the infiltration capacity of these soils is crucial for enhancing soil health and optimizing land‐use efficiency. However, few studies have been conducted to improve soil physical structure and enhance water infiltration and storage capacity in saline‐sodic soils through agricultural waste. This study aims to evaluate the effectiveness of cattle manure amendments in improving water infiltration and related soil properties in dryland saline‐sodic soils. Our results show that mixing cattle manure into the topsoil soil significantly enhances infiltration rates, with the initial and the stable infiltration rates increasing on average by 64.5% and 52.1%, respectively, over the three‐year study period. These improvements are associated with a reduction in bulk density and soil compressive strength by 6.9% and 101.9%, respectively, as well as increases in total porosity, non‐capillary porosity, and soil organic matter by 6.6%, 24.7%, and 8.7%, respectively. In contrast, cattle manure mulching in the topsoil has no significant impact on infiltration and soil properties. Structural equation models reveal that soil water content, non‐capillary porosity, and total porosity are the primary properties influencing the stable infiltration rates, whereas total porosity, soil compressive strength, and non‐capillary porosity are key factors affecting the initial infiltration rate. Our findings demonstrated that incorporating cattle manure into the soil can effectively enhance the soil porosity properties, infiltrability, and organic matter content of saline‐sodic soils. These findings highlight the potential of cattle manure to improve soil physical properties and enhance water infiltration in low‐infiltrability saline‐sodic soils, offering a theoretical basis for addressing this issue in semiarid regions.

Reducing the density of fired ceramic products

Fired brick is one of the most widespread building materials, in the manufacture of which, in addition to strength, great emphasis is placed on the thermal insulation capacity of products. Reduction in bulk density is essential to further improve thermal insulation performance. During our work, in addition to adding sawdust of different fractions, we reduced the bulk density of the fired ceramic samples by mixing 10, 20, and 30 vol% expanded perlite. For the experiments, clay masses were prepared with a laboratory pan mill with a moisture content of 22 wt%. The formed and dried samples were fired at 870 °C for 4 hours. The body density of the samples decreased from 1708 to 1295 kg/m3 as the mixing rate of expanded perlite increased. The coefficient of thermal conductivity decreased significantly, the lowest value was 0.16 W/m·K. Thermal insulation capacity can be improved without significant reduction in compressive strength, by mixing expanded perlite.