Increase In Bulk Density Research Articles

Soil organic carbon and nitrogen reduction through cattle-path induced erosion in montane grasslands, KwaZulu-Natal, South Africa

The impact of daily cattle migration from homesteads to higher altitude pastures creates severe erosion in the montane grasslands of the predominantly subsistence agricultural rural communities of KwaZulu-Natal, Drakensberg, South Africa. This study quantifies the impact of a degraded cattle path at up, mid and downslope positions on SOC and N distribution in the soil profile and within the soil aggregates. An attempt to evaluate sites of erosion and deposition using excess lead-210 (210Pbex) to support our findings was conducted. On average, the degraded cattle path reduced SOC and N in the bulk soil (by 3–4 times, respectively) and was associated with 53% reduction in aggregate stability and a 14% increase in soil bulk density over the non-degraded reference site. These results reflect the loss of vegetation cover (correlated positively to SOC and N (r ≈ 0.94)), which were triggered by cattle grazing and trampling leading to top-soil loss. Cattle hoofs damage the grass and breakdown soil aggregates, exposing the fertile topsoil particles to detachment and consequential transportation via rill and sheet erosion. This is supported by the loss of 210Pbex in the topsoil of the degraded slope positions relative to the reference site. Consistent down core mixing of 210Pbex activity in degraded slope sites supports evidence of cattle mediated soil mixing. Our findings highlight the accelerated land degradation that results from uncontrolled grazing and movement of cattle on sloping lands in the Okhombe Valley. Developing an integrated management strategy co-led by local communities to develop proactive participatory sustainable land use practices is critical for long-term landscape maintenance and recovery in the region.

Utilization of all components of waste concrete: Recycled aggregate strengthening, recycled fine powder activity, composite recycled concrete and life cycle assessment

Waste concrete can be crushed to produce a large amount of recycled aggregate(RA) and recycled fine powder(RFP). Different recycled components have different characteristics. RA should focus on its pretreatment method, while RFP should focus on its morphology and volcanic ash activity. This study investigated the effects of two single and composite strengthening methods in RA, mechanical vibration and acid solution immersion. The results showed that the composite strengthening method was more effective in improving the properties of RA, which resulted in an increase in apparent density and bulk density by 5.59 % and 12.55 %, respectively, and a decrease in crush value and water absorption by 26.05 % and 15.52 %, respectively. Three methods were used to analyze the volcanic ash activity of RFP with different particle sizes, and the RFP with a particle size of 23.08 μm has a high volcanic ash activity, which can effectively play its role of filling and volcanic ash activity in recycled concrete. Based on the preferred pre-treated RA and RFP, the effect of RA and RFP on the macroscopic and microscopic properties of recycled concrete under different mixing amounts was studied, and the results showed that the compressive strength of 20 % RA single mixing could reach 40.17 MPa, and that the compressive strength of 20 % RFP single mixing could reach 38.6 MPa, and both of them had no significant effect on the frost resistance. Further, 20 % RA and 20 % RFP were compounded to prepare recycled concrete, and the results showed that the compressive strength of RA-RFP was slightly improved to 40.12 MPa, and the mechanism of its action was explained by microscopic analysis. Finally, the environmental impact and carbon emission reduction of the life cycle of RA and RFP were evaluated, and the results showed that the utilization of recycled materials can play an effective environmental benefit.

Effect of Coal Ash Enriched Compost on Soil Chemical Properties of Ultisols

Ultisols are soils that develop in humid tropical areas and are formed due to an intensive leaching process, resulting in the accumulation of clay in the subsoil. A decrease in the chemical-physical properties of Ultisols, such as a decrease in the levels of organic C, total N, cation exchange capacity (CEC), base saturation, and on the other hand, an increase in Al saturation and soil bulk density, can occur as a result of continuous monoculture cultivation. Improving the quality of degraded soil is usually carried out by amelioration using compost. Still, the addition of compost often only has a significant effect on improving the physical properties of the soil. Coal ash in the form of fly ash-bottom ash (FABA) is a waste product from burning coal in electric steam power plants. The amount of FABA is very abundant and its utilization is minimal. FABA has an alkaline pH and contains various nutrients in varying amounts. Therefore FABA has the potential to be used as an ameliorant to improve the chemical properties of acid soils such as Ultisols. Experiments with the spread technique of compost+FABA at a dose of 50 tons/ha and in rows technique at a dose of 25 tons/ha, 15 tons/ha, and 5 tons/ha were conducted to determine the effect of the treatment on soil chemical properties. Application of FABA-enriched compost in rows technique at a dose of 25 tons/ha had a significant effect and showed the best soil chemical properties, including increasing organic C, total N, total P, available P, exch-K, -Ca, -Mg, and -Na, CEC, base saturation, and decreased Al saturation. Utilization of FABA as a soil ameliorant combined with compost can improve soil quality more effectively.

Study on packing characteristics of powders with surface modification by nanoparticles

Powders with coated nanoparticles on the surface as a surface modification technique can alter the surface texture of the particles. This paper explored the additional number of nanoparticles on powder packing characteristics. The adhesion mode of nanoparticles and its influence on the inter-particle force in the system were discussed. The study found that the bulk density first increases and then decreases as the content of nanoparticles increases. The incorporation of nanoparticles reduces the inter-particle force, with the optimal mass fraction of nanoparticles being 0.25%, resulting in a 4.43% increase in bulk density. The attachment mode of nanoparticles was observed and analyzed through SEM, with five possible contact modes between particles identified. The change in the inter-particle force was quantitatively analyzed through the probability of each mode. The Bo number was used to establish a prediction model for bulk density, which yielded a highly accurate prediction.

Linking soil physical quality to shoot and root biomass production in scenarios of sugarcane straw removal

Understanding how sugarcane straw removal affects soil physical attributes and root development over successive cultivation years is critical for sustainable straw-based bioenergy production. The aim of this study was to evaluate the effects of straw removal on soil physical quality and its relationship with sugarcane root development and crop yield in soils with contrasting textures. Three straw removal rates corresponding to total removal (TR), moderate removal (MR), and no removal (NR) were arranged in a randomized block design with four replicates. Soil was sampled at depths of 0–0.10, 0.10–0.20, and 0.20–0.40 m to determine soil bulk density, macro- and microporosity, soil penetration resistance, and carbon stock. Annual assessments of sugarcane root and stalk dry biomass were conducted. Overall, excessive straw removal rates were detrimental to soil porosity, C stock, and increased bulk density in the surface layer over successive years compared to moderate and no removal rates. Higher soil penetration resistance levels were observed under total removal, reaching values of 2.6 MPa in the 0–0.10 m layer in both soils. Average reductions in root biomass of 23–33% were verified at moderate and total removal rates in both soils, which affected sugarcane stalk yield, with maximum losses of 24% over crop cycles in the clayey soil. In the sandy loam soil, increases in soil C were correlated with reduced soil penetration resistance, which positively influenced root biomass production. Soil compaction over the years was particularly detrimental in the clayey soil, where the biomass production performance of sugarcane roots and stalk yield decreased in response to increased soil bulk density. Our results suggest that reductions in root biomass may occur in response to straw removal, as well as the loss of soil physical quality induced by soil compaction, with negative effects on C accumulation and soil resistance to root penetration.

The influence of the relief on the formation of the trail network within the forest ecosystems of the NPP «Boikivshchyna» (Verkhovynsky Vododilny ridge, Ukrainian Carpathians)

The influence of recreational load on soil cover is considered. It was found out that in the depressions of the slopes and on the leveled areas there is an accumulation of forest litter, the power and reserves of which depend on the steepness of the slope, the direction of the path and the recreational load. The influence of recreational load on the physical and water-physical properties of brown mountain-forest soils was analyzed. It was found that the complete or partial absence of litter on the paths causes rapid evaporation of moisture from the upper horizon (0−5 cm) of the soil, a decrease in the overall porosity, and an increase soil bulk density. It was found that as the soil bulk density increases, the water permeability of the soil decreases, compared to the control. A significant increase in structure density indicators was found on paths with a significant steepness of the slope, and the obtained results are characteristic of the transitional Нr horizon of brown mountain-forest soils. On the contrary, stagnation of water begins to form in the micro-lowering or on the concave surface of the path, which leads to the formation of new bypass paths. The forest floor in such areas is partially peated, and the F+H capacity of the sub-horizon can be more than 50% of its total capacity. The fractional composition is dominated by the share of leaves and fruits. According to the proposed ecological criteria for assessing the state of the natural environment, namely: the width of the path, the absence/presence of forest litter on the path, the density of the soil structure, the presence of additional/parallel paths, the depth of the erosion cut, it was established that the state of the path leading to the town of Pikuy from of the village of Verkhne Gusne corresponds to category III. It was found that the width of the trail is 1.80-3.50 m, and the stock of forest litter is less than 1 kg·m⁻², and the density of soil structure on the trail increased by 1.5 times compared to the control. As a result of significant overconsolidation of the upper horizons on the path within the forest ecosystems, erosion processes occur, as evidenced by the depth of the ravine of 35-50 cm. In order to improve the ecological condition of the trail or slow down the degradation processes, it is advisable to introduce organizational, management and engineering measures.

Tracking Soil Health Changes in a Management-Intensive Grazing Agroecosystem

Management-intensive Grazing (MiG) has been proposed to sustainably intensify agroecosystems through careful management of livestock rotations on pastureland. However, there is little research on the soil health impacts of transitioning from irrigated cropland to irrigated MiG pasture with continuous livestock rotation. We analyzed ten soil health indicators using the Soil Management Assessment Framework (SMAF) to identify changes in nutrient status and soil physical, biological, and chemical health five to six years after converting irrigated cropland to irrigated pastureland under MiG. Significant improvements in biological soil health indicators and significant degradation in bulk density, a physical soil health indicator, were observed. Removal of tillage and increased organic matter inputs may have led to increases in β-glucosidase, microbial biomass carbon, and potentially mineralizable nitrogen, all of which are biological indicators of soil health. Conversely, trampling by grazing cattle has led to increased bulk density and, thus, a reduction in soil physical health. Nutrient status was relatively stable, with combined manure and fertilizer inputs leading to stabilized plant-available phosphorous (P) and increased potassium (K) soil concentrations. Although mixed effects on soil health were present, overall soil health did increase, and the MiG system appeared to have greater overall soil health as compared to results generated four to five years earlier. When utilizing MiG in irrigated pastures, balancing the deleterious effects of soil compaction with grazing needs to be considered to maintain long-term soil health.

Evaluation of compactioning impact of tractor train running systems on soil on the basis of wheeled tractor of 14 KN traction class

A comparative assessment of the compliance of the compacting effect of the MTZ-80-2PTS-4M (tractor transport aggregate) movers with the established standards on the soil under operating conditions was made. The average density of soil composition on the stubble and the field for sowing in the horizon of 0-50 cm along the track of the trailer with a minimum and maximum load on the mover exceeded the control data by 28.9-31.2% and 38.2-42.3, respectively. The increase in bulk density and hardness of the treated soil was higher on average by 9.5-11% and 5.5-9.5%, respectively in comparison with the stubble background. The excess of the established norms for the mechanical impact of movers on the soil for the maximum specific pressure was 35.3-45.9% over the entire range of loads on the mover and for the maximum normal stress in the soil was 21.9% at maximum load. Under test conditions, the running system of the 2PTS-4M trailer did not ensure compliance with the established standards for the impact on the soil within the entire range of changes in operational loads on the movers.

Study on soil hydraulic properties of slope farmlands with different degrees of erosion degradation in a typical black soil region.

In order to explore the impact of soil erosion degradation on soil hydraulic properties of slope farmland in a typical black soil region, typical black soils with three degrees of erosion degradation (light, moderate and heavy) were selected as the research objects. The saturated hydraulic conductivity, water holding capacity and water supply capacity of the soils were analyzed, as well as their correlations with soil physicochemical properties. The results showed that the saturated hydraulic conductivity of black soils in slope farmlands decreased with erosion degradation degree, which was higher in 0-10 cm soil layer than in 10-20 cm soil layer. The water holding capacity and water supplying capacity of typical black soils also decreased with the increase of erosion degradation degree, and both of them were stronger in the upper soil than in the lower soil. With the aggravation of erosion degradation of black soils, soil organic matter content decreased while soil bulk density increased, leading to the decline of soil hydraulic conductivity. The increase of soil bulk density and the decrease of contents of organic matter and >0.25 mm water stable aggregates were the main factors leading to the decrease of soil water holding capacity. These findings provide scientific basis and basic data for rational utilization of soil water, improvement of land productivity and prevention of soil erosion.

Physicochemical and bioactive constituents, microbial counts, and color components of spray-dried Syzygium cumini L. pulp powder stored in different packaging materials under two controlled environmental conditions.

Currently, the demand for functional food items that impart health benefits has been rising. Blackberry (Syzygium cumini L.) fruit has high anthocyanin content and other functional attributes. However, this seasonal fruit is highly perishable, and a large proportion of it goes unharvested and wasted worldwide. Spray drying of the fruit pulp can impart improved shelf life, ensuring long-term availability for consumers to exploit its health benefits. The storage quality varies according to the type of packaging material and the storage environment. Therefore, in this study, the shelf life span of the spray-dried Syzygium cumini L. pulp powder (SSCPP) was investigated during 6 months of storage under three types of packaging materials (i.e., polystyrene, metalized polyester, and 4-ply laminates) in a low-temperature environmental (LTE) and at ambient environmental conditions. The physicochemical stability of bioactive principles (TPC and TAC), microbial counts, and color components were analyzed at 0, 2, 4, and 6 months of storage. There was a significant gradual loss of dispersibility and solubility with an increase in flowability, bulk density, and wettability during the entire storage period for all three packaging materials. The TSS, pH, TPC, TAC, and microbial counts decreased in the SSCPP both at ambient and LTE conditions during the study. Among all the packaging materials, the 4-ply laminate was found to be the most appropriate and safe for storage of spray-dried SCPP at LTE conditions.

Customise the seeds, not the seeder: Pelleting of small-seeded species for ecological restoration

Direct native seed planting is a cost-effective and popular approach for restoring degraded terrestrial ecosystems. However, the handling and precision seeding of multispecies mixes with diverse seed sizes, and shapes is logistically complex, requires highly customised equipment and often results in poor seedling establishment. This issue is accentuated in small-seeded species, where handling difficulties and a lack of precision placement result in seed wastage. The agricultural seed sector relies on the application of external material to small seeds to improve handling via seed pelleting. Yet this method has been rarely tested on small-seeded native species for ecological restoration.We pelleted the seeds of 15 small-seeded Myrtaceae species commonly used for seed-based restoration programs and recorded a range of physical traits. Prior to pelleting, each seed batch was tested for purity and viability and processed to improve quality (Pure Live Seed, PLS%). Seedling emergence from pelleted and control seeds was tested in controlled laboratory conditions and at two field sites in Western Australia. We linked seedling's emergence outcomes to the degree of physical modification achieved via pelleting to understand which trait would be responsible for a potential decrease or delay in emergence.Seed processing improved the average quality (PLS%) across all species from 23.4 ± 4.8% to 83.6 ± 2.3%. Seed pelleting, on average, resulted in a 27-fold increase in volume, a 30-fold increase in weight, and a 26% increase in bulk density. Seedling emergence response to pelleting varied among species, but on average, emergence speed was 3.1 days faster (p < 0.001) for pelleted seeds, while final emergence was not significantly different (p = 0.217).The results show that a combination of seed processing and pelleting can be used to increase and standardise seed physical properties for improved handling and precision seeding, with limited consequences on seedling emergence and faster emergence. This novel approach could enable the use of large-scale agricultural seeding equipment for rapid and cost-effective delivery of multispecies native seed mixes in biodiverse global restoration programs.

The Influence of Short-Term Tillage, Compost, and Beneficial Microbes on Soil Properties and the Productivity of Wheat and Cowpea Crops

Tillage systems comprise physical, chemical, and biological modification processes that influence soil properties. Soil cultivation aims to create favorable conditions for the development and growth of crops, as evident in their yields. Three growing seasons (winter 2019/2020 (wheat), summer 2020 (cowpea), and winter 2020/2021 (wheat)) were studied in field experiments in Sidi Salem, Kafr El-Sheikh, Egypt, to investigate the effects of soil tillage and the application of organic and beneficial microbes on various biological, chemical, and physical properties of soil and its productivity. Three replicates of the experimental treatments were set up in a split-plot design, in which there were four main plots: conventional soil tillage (ST) treatment for all three seasons (ST1); tillage in the first and second seasons (ST2); tillage only in the first season (ST3); and no tillage for all three seasons (ST4). However, the subplots (soil additives) were conditioned as follows: without treatment (control, T1); compost (C, T2); beneficial microorganisms (BM, T3); and combination (C + BM, T4). The biological property results showed that ST4T4 treatment produced high levels of microbial communities (bacteria, fungi, and actinomycetes), as well as high levels of soil enzyme activity (dehydrogenase, urease, and phosphatase), during the three growing seasons. However, the second season produced high numbers and dry weights of cowpea plants’ nodules. Additionally, changes in the chemical and physical properties showed that the application of various soil tillage treatments during the examined seasons led to significant increases in electrical conductivity (ECe, dSm−1), bulk density (BD, kg m−3), and soil infiltration rate (IR, cm h−1), following the trend of ST4 &gt; ST3 &gt; ST2 &gt; ST1. In contrast, the results revealed decreases in the exchangeable sodium percentage (ESP, %), porosity (PO, %), soil aggregates (stable aggregates and optimal-sized aggregates, %), and soil penetration resistance (SPRa, Mpa). The combination treatment (ST4T4) provided the best yields, with grain yields of 4.991 and 5.325 tons ha−1 and straw yields of 5.214 and 5.338 tons ha−1 in the first and third seasons (wheat), respectively. Cowpea plants showed the same pattern in the second season. Therefore, improvements in soil properties and enhancements in biological activity help maintain its productivity and fertility through simplified tillage processes that reduce interference with the soil surface layer.

Sintering properties and microstructure of Al2O3-TiO2-CaO composite materials based on ferrotitanium slag

In this work, the phase composition and microstructure evolution of the Al2O3-TiO2-CaO composite materials were studied by sintering titanium-ferroalloy smelting slag at temperatures ranging from 1300 to 1600 °C for 3 h. Combined with thermodynamic calculation and mechanical property analysis, it could be seen that with the increase of sintering temperature, Ca ((Al0.84Ti0.16)2)6O19 in ferrotitanium slag was decomposed into CaAl12O19, and the titanium-containing components were dissolved to form free rutile and CaTiO3. The essence of the sintering behavior of the material was the liquid phase sintering, due to the presence of impurity components, the liquid phase started to form in the system at 850 °C with a content of 0.79 wt%, and the amount of the liquid phase gradually increased with increasing temperature, and reached a content of 33 wt% at 1600 °C when it was mainly the transformation of CaTiO3, Al2TiO5, and TiO2. In addition, the elevated temperature was helpful to promote sintering, resulting in larger grain sizes, reduced pore volume (0.0514–0.0133 ml/g) and porosity (33.68%–13.11%), and increased bulk density (2.55–3.32 g/cm3), flexural strength (7.57–36.67 MPa), and compressive strength (24.32–97.03 MPa) of the material.

Sound absorption performance of natural areca plant husk fibers: Experimental and theoretical study

Fibers extracted from plant wastes can be used for sound absorption (SA) applications in vehicles due to its lightweight and porosity. The SA capability of raw areca fibers bundle (RAFB) as a function of the density and thickness of the test specimen is analyzed. Experimental results obtained using the impedance tube approach reveal that an increase in the specimen bulk density and thickness improves the SA capability of RAFB. Similarly, hollow air volume behind the sample enhances the SA in the lower frequency range. Theoretical results predicted using the Johnson–Champoux–Allard model match well with the experimental predictions. The ability of the RAFB to absorb sound is demonstrated to be equivalent to other commercially available natural and artificial fibers by comparing the results available in the literature.

Freeze-thaw desertification of alpine meadow in Qilian Mountains and the implications for alpine ecosystem management

Freeze-thaw desertification (FTD) as a specific land degeneration form in high elevations is intensifying in alpine meadows due to climate change and human activities. It causes the formation of desertified patches (DPs), and further aggravating alpine meadow patchiness and impairing ecosystem functions such as water conservation, carbon sequestration and biodiversity maintenance. However, the impacts of FTD on the patch pattern, soil properties, and vegetation succession of alpine meadows and the elevation differences of these impacts still lack a comprehensive understanding. Here, we analyzed the patch patterns, soil and vegetation characteristics in typical FTD regions in the Qilian Mountains using aerial photography and field investigations along an elevation gradient. Our results indicated that, as elevation increases, the fragmentation of alpine meadows caused by FTD intensified, which was related to the elevational differentiation of freeze–thaw cycles and soil water holding capacity. DPs not only led to a decrease in soil water holding capacity and an increase in bulk density, but also caused surface soil sandification. Among them, the weakening of soil water holding capacity by DPs was particularly serious in high elevations. Additionally, the degradation of the original vegetation species communities in DPs caused the significant loss of vegetation cover, biomass and soil organic carbon, and made DPs exhibit certain alpine desert steppe characteristics, whereas the vegetation diversity of DPs had an increase at low elevations. Our findings highlight the significant impacts of FTD on the water conservation function and vegetation diversity of alpine meadows, and it is necessary to apply ecological protection measures to control DPs expansion such as fenced grazing, biological control and land cover (crop, vegetation, degradable plastic mulch, etc.).

Spatial Properties of Soil Physical Quality Index S in Black Soil Croplands under Permanent Gully Erosion

Soil physical quality (SPQ) is a limiting factor affecting crop production. However, the impact of gully erosion on the SPQ index S, defined by Dexter as the inflection point of the soil water retention curve (SWRC), remains unclear, especially when considering different latitudinal regions. This study aimed to apply Dexter’s S-theory to evaluate the distribution of index S in black soils adjacent to various gully positions and investigate its relationship with bulk density (Bd), soil organic matter (SOM), and particle percentage. Soil properties (SWRC, Bd, SOM, and particle percentage) from nine gullies in croplands in three latitudinal regions (Harbin, Hailun, and Nenjiang in Heilongjiang province) were determined at the gully edge (GE0) and 50 m beyond the edge into the croplands (GE50) at the following gully units: head, mid-upper, middle, mid-lower, tail, and conjunctions between main gully and gully branch. The S-index was calculated using parameters such as n, θs, and θr, with SWRC data fitted into the van Genuchten model. The results showed spatial variations in the S-index across latitudinal regions, with slightly higher S-values in Harbin than in Hailun and Nenjiang. The S-index also showed noticeable differences at GE0 and GE50 and at the junctions between the main gully and its branches. Approximately 51% of the samples at GE0 and 28.2% of the samples at GE50 had S-values below 0.035, which Dexter proposed as the boundary between good and poor SPQ, indicating a degradation of SPQ at the gully-surrounding areas. A decreased S-index in the gully vicinity was significantly (p &lt; 0.05) associated with increased bulk density (1.33 vs. 1.21 g cm−3 for GE0 and GE50) and decreased SOM (36.80 vs. 39.36 g kg−1 for GE0 and GE50). In summary, this study indicates that gully erosion affects the farmland S-index at the gully-surrounding areas through SOM and Bd. Accordingly, measures suited to the increase in the S-index of the gully-surrounding areas may be implemented to maximize the crop yield of farmlands.

Enhanced medicinal applications of Co-doped Zn0.5Ni0.5Fe2-xO4 for (X = 0.00 and 0.0250) soft ferrites: A structural analysis

In this experimental research paper, we investigate the potential enhancement of Co-doped Zn0.5Ni0.5Fe2-xCoxO4 for (x = 0.0, and 0.0250) ferrites, synthesis by green synthesis method for applications in medicine. The structural analysis of the synthesized material is a crucial step in understanding its suitability for medical applications. X-ray Diffraction (XRD) is employed to elucidate the crystallographic structure of the Co-doped ZnNiFe2O4 ferrites. The results demonstrate that the doping process has a significant influence on the material’s crystal structure, which may impact its potential in various biomedical applications. The Co-doped ZnNiFe2O4 spinel ferrite materials become more suitable for medical applications as the decrease in X-ray density and simultaneous increase in bulk density can facilitate better tissue penetration and biocompatibility, making them ideal for non-invasive medical imaging and therapeutic applications, while minimizing potential health risks.

Physical and Chemical Properties of Hidimundige (Crown Choking) Affected and Healthy Arecanut Gardens of Chitradurga District, Karnataka, India

The present investigation was undertaken at College of Agriculture, Shivamogga during 2018-2019 to delineate the causes for hidimundige syndrome in arecanut. Soil samples from two depths 0 to 30 cm and 30 to 60 cm were collected at 60 cm away from the trunk of arecanut from both healthy and affected gardens of Holalkere, Hiriyur, Chitradurga and Hosadurga taluks. The collected soil samples were analyzed for various physical and chemical properties and also for macro and micro nutrients. The results of the investigation indicated that soils coming under affected gardens showed the high mean clay content than healthy gardens. There was a significant increase in bulk density of affected gardens compared to healthy gardens in Holalkere (from 1.63-1.84 Mg m-3) and Hosadurga (from 1.84-1.96 Mg m-3) taluk at lower depth. Whereas, the drainable porosity decreased significantly in affected gardens compared to healthy gardens of Holalkere (from 33.54-25.69 %) and Hosadurga (from 25.79-21.23 %) taluk at lower depth. In all taluks, majority of the soils from both healthy and affected arecanut gardens were neutral to alkaline in reaction. The study showed that availability of N, P, K, S, Fe, Mn, Cu and B and also the content of exchangeable Ca and Mg was quite heterogeneous in both healthy and affected gardens. Whereas, available zinc status in the soil showed significant decrease in affected gardens compared to healthy gardens of Hiriyur, Chitradurga and Holalkere taluks.

Development of a loose powder sintering method for the preparation of porous ceramic from municipal solid waste incineration fly ash

Loose powder sintering was used to prepare porous ceramic from municipal solid waste incineration fly ash (MSWI FA) and waste glass (WG). Sintering experiments at various temperatures, holding times, Al2O3 and SiC were conducted to investigate their effect on the ceramic properties and volatile heavy metal removal efficiency. The results show that increasing temperature from 1100 °C to 1250 °C promoted the transition of the mixtures from loose powder to a densified sintered matrix, with a bulk density increase of 31.10% and an open porosity decrease of 70.41%. The bulk density of the ceramic increased to 2.44 g/cm3 with 3% Al2O3 addition. The removal rates of Pb, Zn, Cu and Cd were higher than 90% at 1200 °C for 90 min, and promoted by the increasing temperature and holding time. Notably, 3% Al2O3 addition inhibited the volatilisation of Zn, Cu and Cd, particularly for Zn, the removal rate of which reduced to 61.66% at 1200 °C. The bulk density of the ceramic decreased to a minimum value of 1.48 g/cm3 with 4% SiC. The ratio of MSWI FA:WG:Al2O3:borax of 28.3:56.7:10:5 was proposed to obtain ceramic with a bulk density of 1.54 g/cm3 and a water absorption rate of 8.59% at 1150 °C. The leaching concentration of the porous ceramic met the Chinese regulatory standard (GB 8978-1996). Preparation of MSWI FA-based porous ceramics using the powder sintering method is a promising route for the harmless utilisation of MSWI FA. The porous ceramic is potentially applicable as a thermal-insulation building material.

Municipal woody biomass waste ash-based cold-bonded artificial lightweight aggregate produced by one-part alkali-activation method

The rapid industrialization process has resulted in the overconsumption of natural aggregates, leading to significant environmental concerns. Additionally, the disposal of municipal woody biomass ash (MWBA) has caused the depletion of land and further environmental pollution. Hence, production of artificial aggregate using MWBA is of great interest, as it reduces the consumption of natural aggregates and landfill area while recycling the MWBA. The main objective of this study is to determine the optimal mix design that can produce artificial aggregates with satisfactory strength and lightweight properties while maximizing the utilization of MWBA. Following that, the effects of different alkaline contents (9%, 12%, 15%) and ground granulated blast-furnace slag (GGBS) contents (0%, 10%, 20%, 30%) on the physical properties of the MWBA-based AAAs were investigated. Additionally, the pore distribution, phase and elemental compositions of the aggregates were examined to ascertain the mechanism of alkali-activation and strength development of the MWBA-based AAAs. The main result showed that at 15% Na2SiO3·5H2O content, increasing the GGBS content from 0% to 30% resulted in an increase in the loose bulk density and crushing strength of MWBA-based AAAs from 817 kg/m3 to 950 kg/m3 and from 0.84 MPa to 2.25 MPa, respectively, while decreasing the water absorption from 24.0% to 12.5%. This is due to the denser matrix observed, attributed to the GGBS addition, which enhances the effect of alkali-activation. Additionally, a new amorphous phase, namely C-A-S-H, was identified. The Si/Al ratio decreased with the GGBS content, resulting in more C-A-S-H gel formation and a denser microstructure with better performance for the AAAs. The novelty of this study is to demonstrate the feasibility of using MWBA in producing AAAs through a cold-bonded one-part alkali activation method. This method presents an alternative to natural aggregates that can be utilized in concrete.