Sustainable Materials Used as Lightweight Aggregate :(An Overview)

Lightweight aggregates (LWA) are building materials with a lower bulk density than standard construction aggregates. In recent years, the contribution of industry to the circular economy has become a serious concern. Among these, the mining sector is confronted with significant problems relating to the management of a huge quantity of generated waste. The major contemporary task is to address a number of interconnected challenges, including waste management and recycling, conservation of scarce natural resources, reduction of energy use, and reduction of greenhouse gas emissions. Natural aggregates are consumed by the construction materials industry in the range of 8 to 12 billion tons per year. According to reports, the construction materials sector consumes the most energy and scarce natural resources (rocks, aggregates, and water) while also emitting greenhouse gases. In general, using waste material as lightweight aggregate decreases the concrete’s overall weight. The materials used as lightweight aggregate in concrete are discussed in this study. According to research, utilizing trash as a lightweight aggregate not only improves the characteristics of concrete but also gives a sustainable approach to minimize global waste.

Sediment Bulk Density Effects on Benthic Macrofauna Burrowing and Bioturbation Behavior

Benthic macrofauna are a key component of intertidal ecosystems. Their mobility and behavior determine processes like nutrient cycling and the biogeomorphic development of intertidal flats. Many physical drivers of benthic macrofauna behavior, such as sediment grain size, have been well-studied. However, little is known about how sediment bulk density (a measure of sediment compaction and water content) affects this behavior. We investigated the effect of bulk density on the burrowing rate, burrowing depth, bioturbation activity, and oxygen consumption of bivalves (Limecola balthica, Scrobicularia plana, and Cerastoderma edule) and polychaetes (Hediste diversicolor and Arenicola marina) during a 29-day mesocosm experiment. We compared four sediment treatments consisting of two sediments of differing grain size classes (sandy and muddy) with two bulk densities (compact and soft). Overall, bulk density had a strong effect on benthic macrofauna behavior. Benthic macrofauna burrowed faster and bioturbation more intensely in soft sediments with low bulk density, regardless of grain size. In addition, L. balthica burrowed deeper in low bulk density sediment. Finally, we found that larger bivalves (both C. edule and S. plana) burrowed slower in compact sediment than smaller ones. This study shows that benthic macrofauna change their behavior in subtle but important ways under different sediment bulk densities which could affect animal-sediment interactions and tidal flat biogeomorphology. We conclude that lower bulk density conditions lead to more active macrofaunal movement and sediment reworking.

Development of Well-Porous Structured Leavened Food Product from Rice-based Composite Flour

Well-porous structured leavened food products with a proper texture have a high demand in the dynamic food market. Hence, the current study was focused to formulate a leavened food product with a proper porous and better-textured crumb using rice-based composite flour (CF). Nine CF samples were prepared according to Taguchi’s orthogonal array by taking three variables (corn flour, finger millet flour, green gram flour) at three levels (0, 5%, 10%). Nine dough samples were prepared from each CF sample and subjected to fermentation and gelatinization under 1 kg/cm2 initial air pressure condition. Results revealed that crumb sample prepared from CF4 (Rice: Wheat: Corn: Green gram, 50:40:5:5) showed higher crumb volume, specific volume, lower bulk density and better crumb cellular structure properties which did not significantly different (p>0.05) to CF1 (Rice: Wheat, 50:50). Further, CF4 imparted to have the lowest crumb hardness, gumminess and chewiness. Thus, CF4 was selected as the best CF sample, which yielded a leavened food product with better textural and structural properties. Keywords: composite flour, fermentation, porous-crumb structure, rice flour, Taguchi’s orthogonal array

Long-term conservation agriculture and best nutrient management improves productivity and profitability coupled with soil properties of a maize–chickpea rotation

Conservation agriculture (CA)-based practices have been promoted and recouped, as they hold the potential to enhance farm profits besides a consistent improvement in soil properties. A 7 years' field experiment consisting of three crop establishment practices viz., zero-till flatbed (ZTFB), permanent beds (PNB), conventional system (CT) along with the three-nutrient management; nutrient expert-based application (NE), recommended fertilization (RDF), and farmers’ fertilizer practice (FFP), was carried out from 2013 to 2020. The CA-based practices (ZTFB/PNB) produced 13.9–17.6% greater maize grain-equivalent yield (MGEY) compared to the CT, while NE and RDF had 10.7–20% greater MGEY than the FFP. PNB and ZTFB gave 28.8% and 24% additional net returns than CT, while NE and RDF had 22.8% and 17.4% greater returns, respectively over FFP. PNB and ZTFB had 2.3–4.1% (0.0–0.20 m soil layers) lower bulk density than the CT. Furthermore, microbial biomass carbon (MBC) increased by 8–19% (0.0–0.50 m soil layers) in ZTFB/PNB over the CT, and by 7.6–11.0% in NE/RDF over FFP. Hence, CA-based crop establishment coupled with the NE or RDF could enhance the yields, farm profits, soil properties of the maize–chickpea rotation, thereby, could sustain production in the long run.

Impacts of soil and water conservation measures and slope position on selected soil attributes at a watershed scale

Background: The Ethiopian highlands are affected by soil loss caused by soil erosion resulted in soil properties deterioration. To reverse this, different soil and water conservation (SWC) measures were spatially practiced; however, the effect of SWC and slope gradient on soil properties is not studied well in the area. Hence, this study was conducted to evaluate the effects of SWC and slope gradient on selected soil physicochemical properties at Dawnt watershed, North-western Ethiopia. The treatments were a combination of four different SWC measures with three slope gradients replicated at three sites. Disturbed and undisturbed soil samples were collected from 0-20cm soil depth and physicochemical properties were determined following standard laboratory procedures. Results: The lab results depict that sand, bulk density, moisture, particle density, porosity, pH, organic carbon (OC), cation exchange capacity (CEC), total nitrogen, and available phosphorus were significantly (P<0.05) affected by SWC measures and slope gradient. High OC (2.44%), CEC (45cmol (+) kg-1), and moisture (19.55%) were obtained from Stone-Faced Soil Bund stabilized with Grass (SFSBG) and high available phosphorus (7.83ppm) from Soil Bund (SB) while lower bulk density (1.13gm/cm3) from SFSBG. Additionally, higher clay (41.67%) and moisture (19.81%) and lower bulk density (1.14g/cm3) were obtained from the lower slope. Higher pH (6.75) and OC (2.89%) were recorded at lower slope under SFSBG and lower pH and OC (6.03 and 1.02%) at the upper slope with non-conserved. Soil chemical properties, except available potassium, were increased down the slope.Conclusion: The interactions of slope position and SWC measures affect soil texture; pH, organic carbon, and available phosphorus but do not affect soil bulk density, moisture content, particle density, total porosity, cation exchange capacity, total nitrogen, and available potassium. In generally, the soil properties were improved through integrating conservation practices with multipurpose grass species across the study watershed. Therefore, in the study watershed and other similar agro-ecologies, farmers should use integrated SWC measures to avert the rainfall-driven soil nutrient loss.

Physical Soil Quality of Semi - Arid Savanna as Influenced by Acacia senegalensis in Desert Research Experimental Plot Yobe State University Damaturu, Northern Nigeria

Soil is a living and dynamic natural reservoir and source of plant nutrients that play numerous key roles in terrestrial ecosystems. This study investigated the impact of three adjacent land use systems (Acacia senegalensis plantation (ACP), pilostigma raticulatum plantation (PRP) and Ground nut field (GNF) on selected soil physical quality indicators in a Northern Nigeria semi- arid Savanna. Minimum data set for assessing soil quality (Prime quality agricultural land) in this study include bulk density, organic carbon content, total nitrogen, carbon stock, available phosphorus and pH values obtained from DRMCC research field. Mean values of the data set were arranged and scored to obtain totals among the minimum data set (MDS). Soil quality is considered a key element for evaluating the sustainability of land management practices. Data generated were analyzed using ANOVA and significant means were determined using Duncan multiple range test (DMRT). ACP had significantly higher organic carbon content (9.37 gkg-1) and lower bulk density (2.16 gkg-1) than pilostigma and GNF respectively. The lower bulk density (ρb) and high organic carbon in ACP might be due to high leaf shading by acacia while the lower bulk density in ground nut field aided by trampling induced compaction resulted in its high relative field capacity (RFC), permanent wilting point (PWP) and micro-p ore spaces (PMIC) tillage in ground nut field created loose soil in the plough layer (<20 cm) which turn out to its low bulk density (ρb). Acacia plantation contained highest total nitrogen value (1.23 gkg-1); perhaps resulting Acacia leaf litter is known to have a high decomposition rate. Pilostigma plantation contained (1.22 gkg-1) nitrogen, while the least nitrogen content was obtained under ground nut field. On scoring the land use types and depth against the minimum data set, the least total was that under acacia plantation, followed by pilostigma plantation then ground nut field. Therefore, soils under acacia plantation were ranked best quality (SQ1) for cultivation purposes at 0-10 cm, followed by pilostigma land use type that were ranked SQ2. Ground nut field soils were ranked least (SQ6) in quality for use in crop production at depth of 10-20 cm.

Influence of Foaming Agent Type on The Behavior of Foamed Concrete

In this work the desired aim is to study the effect of two various sorts of a foaming agents on the properties of foamed concrete to obtain high quality with a target density is nearly 1600 kg/m3. The standard samples were designed by employing two types of foam agent (FA), the first one is commercially named (EABSSOC foam agent, FA) while the second is the foam of detergent liquid (D) which known (Fairy). The results showed that the FA sample records the lower bulk density compared to the other types. The perfect mix which involved 1wt.% of (D) had higher values of the compressive strength 20.25MPa, 16.32MPa of the curing in water and air respectively and flexural strength (F.S) values were 6.89MPa,4.47MPa of the cured samples in (air, water) for various durations (7,14 and 28) days compared to the samples that contained 1and 0.8wt. % of FA. The obtained compressive strengths were 5.1MPa, 4.3MPa while the flexural strengths were 2.74MPa, 2.9MPa for the samples contained 1wt. %foam agent (FA) after the curing into water and air at the same duration. It is obvious that the addition of foam to the cement mortar paste imparts great characteristics as lightweight with flowability. These properties and others make it suitable for some applications, for example, a decrease of the dead load from the structure, thermal and acoustic insulating and use it in non-structural sections such as a wall.

Greenhouse Gas Emissions from Subtropical Agriculture Fields Decrease Over Time

Expansion of cultivated lands and field management impacts greenhouse gas (GHG) emissions from agriculture soils. Soils naturally cycle GHGs and can be sources or sinks depending on physical and chemical properties affected by cultivation and management status. We looked at how cultivation history influences GHG emissions from subtropical soils. We measured CO2, N2O, and CH4 fluxes, and soil properties from newly converted and continuously cultivated lands during the summer rainy season in calcareous soils from south Florida. Newly converted soils had more soil organic matter (OM), more moisture, higher porosity, and lower bulk density, leading to more GHG emissions compared to historically cultivated soils. Although more nutrients make newly converted lands more desirable for cultivation, conversion of new areas for agriculture was shown to release more GHGs than cultivated lands. Our data suggest that GHG emissions from agricultural soils may decrease over time with continued cultivation.

Bark Thermal Insulation Panels: An Explorative Study on the Effects of Bark Species

Tree bark is a byproduct of the timber industry which accrues in large amounts, because approximately 10% of the volume a log is bark. Bark is used primarily for low-value applications such as fuel or as a soil covering material in agriculture. Within the present study, thermal insulation panels made from larch, pine, spruce, fir and oak tree bark with different resins (urea formaldehyde, melamine formaldehyde, Quebracho, Mimosa) as a binder are discussed. Also, the properties of panels made from larch bark mixed with industrial popcorn are investigated. The physical-mechanical properties of the panels, which are dependent on panel density, bark species, resin type, resin content and particle size, are analyzed. The bark species has a minor effect on the mechanical characteristics of the panels, while the compression ratio is important for the panel strength, and hence, barks with lower bulk density are preferable. Under laboratory conditions, panels made with green tannin resins proved to have adequate properties for practical use. The addition of popcorn is a means to lower the panel density, but the water absorption of such panels is comparably high. The bark type has a minor effect on the thermal conductivity of the panels; rather, this parameter is predominantly affected by the panel density.

Ferralsol Porosity and Density After Mechanical Scarification and Crop Rotation Systems

With intensive cultivation and the lack of crop rotation, the no-tillage system has been showing compacted areas. For its reduction, mechanical scarification and crop rotation has been recommended. Thus, the present study aimed to evaluate in a no-tillage system the effect of mechanical scarification and crop rotation systems on soil porosity and density after 18 months. The experimental design used was randomized blocks in a split-plot scheme, with four replications. The main plots consisted of maintaining the no-tillage system and minimal soil preparation with a chisel, carried out before the cultivation of cover plants. The subplots were composed of different plant species grown in winter: wheat, consortium of forage pea + black oat and consortium of black oat + forage turnip. Both were succeeded by cultivation of soy and lupin. Macroporosity, microporosity, total porosity and bulk density were evaluated. After 18 months, the scarified soil showed a higher bulk density (0.10-0.15 m layer) when compared to the no-tillage system, demonstrating that this isolated decompression alternative does not improve the physical properties of the soil. The area in succession to oat + turnip/soybean/lupin showed lower bulk density.