Reduced Bulk Density Research Articles

Direct Effects of Stubble Burning on Some Edaphic Characteristics of Coastal Plain Sands at Different Heating Intensities

Stubble burning had been identified as a contributor to soil structural degradation and loss of plant nutrients. Contrary to this, some studies have suggested that burning activities might increase availability of plant nutrients and also reported that charcoal residues and charred biomass left on kiln sites improve the fertility of tropical soils by direct nutrient addition and retention. The effect is not sufficiently understood or quantify in areas with very high rainfall intensity that evidenced in high leaching and erosion associated with slope. We; (1) examined the effect of stubbles burning on soil conditions in acid sands, and (2) identified any changes in soil chemical and physical properties under burning at different level of intensity. The experimental fire was performed with measured dry biomass of 30, 90, 120 kg m- 2 , in three replicates on the plots to provide three levels of burning and the unburned plots served as control. At each of the sampling points, random spots were core sampled and augered at 0-15 cm depth, with the aid of a Dutch auger and bulked together to give a composite sample. Laboratory methods of analyses were carried out on soil samples for particle size distribution, pH (soil reaction), organic matter contents, total nitrogen, available phosphorus and exchangeable cations (K, Ca, Mg and Na). The textural class of the soils within the study area was found to be sandy loam with sand fraction being the dominant particle size in all locations after burning and was found to have significant effect on the particle size distribution. Coarse sand fraction was higher in the burnt plot with the mean value of 16.00 gkg -1 in 30 and 120 kgm- 2 , 13.33 gkg -1 in 90 kgm- 2 and 12.66 gkg -1 in the unburnt plot. Also soil burnt with 30 and 90 kgm- 2 of the dry biomass was found to increase bulk density by 4 and 9 % respectively, while 6 % reduction in bulk density occurred in soil burnt with 120 kgm- 2 stubble materials. Total nitrogen content was found to be significantly reduced as a result of burning, while available phosphorus was higher in burnt plots than in the un-burned soil.

Zmena vybraných fyzikálnych vlastností černozeme hnedozemnej po siedmich rokoch bezorbového spracovania

Soil physical properties were investigated in two types of growing systems - integrated no-till system and conventional system with ploughing, in 1999 – 2005 on chernozem in maize growing region. Bulk density decreased and total porosity increased during 7 years in both growing systems. In integrated system the improvement of soil physical properties could be explained by remaining of plant residues on soil surface. In conventional system the plant residues were incorporated into soil by ploughing. This led to the higher proportion of organic matter in soil. Soil cultivated conventionally had significantly higher value of reduced bulk density, significantly lower porosity and significantly higher values of soil moisture compared to soil in integrated no-till system. Maximum capillary water capacity was not significantly influenced by soil cultivation. Values of investigated soil physical properties in both systems were not markedly different from the typical values of cultivated chernozem.

Effect of afforestation of agricultural soils and tree species composition on soil physical characteristics changes

AbstractThis paper deals with the evaluation of the effect of afforestation of previously arable land to soil characteristics changes. One of the main aims was to evaluate the effects of each forest species on the soil structure quality after afforestation. Soil samples were taken at two climatically distinct subregions within the Czech Republic. Based on the different site conditions, two study sites were chosen at each locality for a total of four research sites. Detailed soil survey and basic forest stand inventories were conducted at all four sites. The first locality was established in the Rychnov nad Kněžnou district in the Protected Landscape Area of the Orlické mountains (soil type a Haplic Cambisol). The second locality was established in the Prague-East district (soil type a Haplic Cambisol and a Haplic Stagnosol). Afforestation had a positive influence on the soil physical characteristics which are important for the maintenance of soil stability. Forest cover has a major influence on increasing the soil porosity, by decreasing the reduced bulk density and increasing capillary and gravitational pores, which is crucial. Afforestation was also found to be positively related to increases in soil organic matter content in different forms, both stable and unstable, and tendency of considerable soil organic matter accumulation not only in the layer of surface humus but also in the entire soil profiles of the research sites. The main contributor to soil improvement after afforestation is the formation of stable soil aggregates. This is typical also for spruce and pine cover.

Effect of soil tillage and digestate application on some soil properties

The effect of different methods of tillage on basic physical and chemical properties of soil was tested in a pilot field experiment. The digestate was applied simultaneously and it was tested if this type of dressing did not influence soil in a negative manner. Results obtained in the Variant 2 (i.e. with the minimum tillage) indicated that, as compared with the conventional ploughing, (Variant 1) values of reduced bulk density were increased and those of soil porosity decreased. However, better values of soil humidity were recorded in Variant 2. In Variant 2, a certain trend to increasing values of Corg/Nt ratio was observed while in Variant 1 values of soil reaction were decreased. It was concluded that these changes could induce soil degradation processes.

Bulk Density Reduction of Injection Molded Thermoplastic Foams via a Mold Design Approach

This study investigates the inter-relationships amongst processing parameters and mold design and their effects on relative density of injection molded foams. The limitation in lowering the overall bulk density of polymeric foams is one of the main drawbacks in injection foaming process. A sheet mold with a rectangular cavity was designed and manufactured which, includes an overflow channel connected with the main cavity via a secondary gate, the size of which was varied in this research. The effects of three parameters including chemical blowing agent weight percentage, gate width, and part thickness on reduction of relative density were investigated. Full factorial test experiments were applied in this research work. The results were used to determine the optimum conditions in terms of low foam bulk density and high cell density. The results showed that enhanced cell structure can be achieved at a larger part thickness and adjusting the secondary gate to an optimum thickness. The conclusions revealed that part thickness and secondary gate width were the most influential factors on reduction of relative density and part weight.

Positive effects of afforestation efforts on the health of urban soils

Large-scale tree planting projects in cities are increasingly implemented as a strategy to improve the urban environment. Trees provide multiple benefits in cities, including reduction of urban temperatures, improved air quality, mitigation of storm-water run-off, and provision of wildlife habitat. How urban afforestation affects the properties and functions of urban soils, however, is largely unknown. As healthy soils are critical for vigorous tree growth, our study explores the impact of soil restoration as part of a large-scale urban afforestation project. We collected data on multiple soil variables over the first three years of the New York City Afforestation Project (NY-CAP). The study consists of 56 plots of 225m2 arrayed across an urban parkland in Queens, NYC. Each plot contains 56 trees made up of two (low richness) versus six (high richness) native species. The richness treatment was crossed with stand complexity (with shrubs and herbs versus without), and soil amendment (with compost versus without). We sampled soils in 2009 prior to project establishment, in 2010 following site preparation but just prior to planting, and again in 2011 one year after the 3–5year old saplings were planted and plot treatments were put in place. We present results for the effects of site preparation on soil properties over time from baseline conditions in 2009 through the first year of afforestation in 2011. We also explore the impact of plot treatments (listed above and implemented right after our 2010 soil sampling) on soil parameters in 2011. Overall, site preparation improves soil conditions for the native tree saplings across time, with reductions in bulk density from ∼1.4 to 0.72gcm−3, acidification of the soil from pH 7.36 to 7.03, a 4-fold increase in microbially-available carbon and a 1.3-times increase in microbial biomass. Furthermore, soil carbon concentrations increased by 1.33-times between 2009 and 2011. Exploring plot treatments in 2011, compost had the largest effect, with 1.23-times more microbial biomass in composted plots, more acidic pH values (6.66 versus 7.37 in non-composted plots) and increased water holding capacity (35% versus 31% in non-composted plots). The observed changes in soil physical, chemical and biological properties suggest that site preparation and management improves traits of urban soils that are critical for infiltration, decomposition, mineralization and nutrient retention. The initial trajectories of change in these soil properties provide support for the expectation that urban afforestation – and specifically the preparation of urban soils for tree planting – will improve the health of urban soils and consequently the urban environment.

Use of coir pith particles in composites with Portland cement

Brazil is the fourth largest world's producer of coconut (Cocos nucifera L.). Coconut crops generate several wastes, including, coir pith. Coir pith and short fibers are the byproducts of extracting the long fibers and account for approximately 70% of the mature coconut husk. The main use of coir pith is as an agricultural substrate. Due to its shape and small size (0.075–1.2 mm), this material can be considered as a particulate material. The aim of this study was to evaluate the use of coir pith as an aggregate in cementitious composites and to evaluate the effect of the presence of sand in the performance of these composites. Some composites were produced exclusively with coir pith particles and other composites with coir pith partially substituting the natural sand. The cementitious composites developed were tested for their physical and mechanical properties and characterized by X-ray diffraction, scanning electron microscopy, energy dispersive X-ray spectroscopy and Fourier transform infrared spectroscopy to evaluate the effect of coir pith particles addition in cement paste and sand-cement-mortar. The statistical significance of the results was evaluated by one-way analysis of variance (ANOVA) test followed by multiple comparisons of the means by Tukey's test that showed that the composites with coir pith particles, with or without natural sand, had similar mechanical results, i.e., means were not statistically different at 5% significance level. There was a reduction in bulk density and an improved post-cracking behavior in the composites with coir pith particles compared to conventional mortar and to cement paste. These composites can be used for the production of lightweight, nonstructural building materials, according to the values of compressive strength (3.97–4.35 MPa) and low bulk density (0.99–1.26 g/cm3).

Using wood fiber waste, rice husk ash, and limestone powder waste as cement replacement materials for lightweight concrete blocks

This work presents a parametric experimental study, which investigates the effects of partial replacement of Portland cement by wood fiber waste (WFW), rice husk ash (RHA), and limestone powder waste (LPW) for producing a lightweight concrete block as a building material. Some of the mechanical and physical properties of block materials having various levels of WFW, RHA, and LPW are studied. The compressive strength of the concrete blocks due to the filler effect decreased with increasing cement replacement. However, the results show the effect of 25wt% replacement of RHA and LPW with Portland cement do not exhibit a sudden brittle fracture even beyond the failure loads, indicates high energy absorption capacity, reduce the unit weight dramatically. As expected, the increase of the RHA content induced the reduction of bulk density of the concrete blocks. Statistical analysis showed that the interactions of above-mentioned variable parameters were significant on both mechanical and physical properties at 5% confidence level. The optimum replacement level of WFW, LPW, and RHA was 25% by weight; this replacement percentage resulted in good physico-mechanical properties. Recycling of WSW, RHA, and LPW as promising raw material supplements appears to be viable solution not only to the environmental problem but also to the problem of the economic design of buildings.

Energy saving scoop type rotary tiller blade for deep tillage

The energy consumption for the land preparation is excessive during the primary and secondarytillage operations; because of the high draft force required. Many researchers were reported that thereverse rotational rotary ti lIer had an advantage for the deep ti IIing on the power req uirement comparedto the conventional rotary tiller. The reverse rotational rotary tiller can be used for deep tillage withless energy requirement. Three types of scoop type rotary tiller blades were fabricated by changingdesign parameters of the horizontal portion of the scoop surface of the blade for reverse rotational inorder to minimize the re-tillage during deep tillage achieving low power consumption. Blades withcutting angles 25°, 35 and 55° were tested with conventional blade (45° cutting angle) at 15.6% soilmoisture conditions.When compared the maximum power and the torque at maximum power, blade with angle 35° showedbest performance, while others were in the order of conventional type (45°»55°>25°. In terms of soiltilth, significantly better performances were shown by the blades with angles 35° and 45° with reducingbulk density and cone penetration resistance values. Blade with angle 35° showed highest backwardthrowing distance as 660 mrn. Blade with angle 55° showed lower backward throwing distance.Blade with angle 35° performed best with lowest power consumption, higher pulverization and backwardthrowing ability and can be recommended for reverse rotation in deep tillage.

Implications of municipal wastewater irrigation on soil health from a study in Bangladesh

AbstractThis study evaluated soil health in fields of wheat (Triticum aestivum L. cv Shatabdi) and potatoes (Solanum tuberosum L.) irrigated by different blends of municipal wastewater (hereafter called wastewater). The crops were grown with and without added fertilizers over three consecutive years. The wastewater contained high concentrations of organic carbon (C), nitrogen (N), phosphorus (P), sodium (Na), potassium (K), calcium (Ca), magnesium (Mg), sulphur (S), zinc (Zn) and boron (B). It also contained negligible concentrations of a few heavy metals. Irrigation by wastewater resulted in an increase in the porosity of the surface soil and thus a reduced bulk density. Wastewater enhanced the saturated hydraulic conductivity and water retention capacity of the soils. The organic carbon, total N, available P and S, and exchangeable Na, K, Ca and Mg of the soils increased proportionately with the quantity of applied wastewater. C, N and K increased significantly (α = 0.05) when fields were irrigated using raw wastewater after applied fertilizers; the other elements accumulated in the soil insignificantly under both fertility levels. Electrical conductivity (EC) and pH of the upper 0–20 and 20–40 cm soil layers increased with the application of wastewater; the increase was significant only under raw wastewater irrigation. In the 40–60 cm soil layer, both EC and pH remained unchanged. The applied inorganic fertilizers raised EC but reduced soil pH. The wastewater contained large counts of total coliform (TC: 17.2 × 106 cfu/100 mL) and faecal coliform (FC: 13.4 × 103 cfu/100 mL). Irrigation using municipal wastewater is proposed for improving soil fertility as well as for alleviating water scarcity with the exception of some crops whose edible parts come in direct contact with wastewater and/or are eaten uncooked.

Advances in intergrated nutrient management for crop production in Nigeria

The work is a review of recent developments in utilization of organic and organomineral fertilizers in Nigeria. Integrated crop nutrition entails combined use of organic and inorganic fertilizers to avoid problems associated with sole use of the two sources. The aim is also to reduce need and cost associated with sole use of either source of plant nutrients. Researches conducted on effectiveness of organomineral fertilizers show the following:  Organomineral fertilizers (OMF) gave similar or higher crop yield compared with recommended NPK fertilizer. They also improved nutritional quality and nutrient content and had residual effect than inorganic fertilizer. The OMF also had liming effect.  The OMF reduced need for both organic and inorganic fertilizers which had synergistic effect on each other  The OMF improved soil physical properties compared with inorganic fertilizers as indicated by reduction in bulk density, temperature and conservation of soil moisture.  The OMF improved soil organic matter, nutrient content and increased availability of cations compared with I norganic fertilizer.  Organic wastes that were found to be effective in increasing soil nutrients contents, pH, nutrient uptake by crops and were successfully combined with inorganic fertilizers such as NPK, urea at reduced rates include poultry manure, oil palm bunch ash, cocoa pod ash, kola pod ash and sawdust ash.  The pacesetter and sunshine organic and organomineral fertilizers developed and manufactured in Nigeria have been found to be effective in improving soil fertility, and yield of arable and tree crops. There are abundant organic wastes that could be used alone or combined with mineral fertilizers. The presence of organic manures in organomineral fertilizers ensures more residual effect, balanced nutrition and improvement in soil physicochemical properties. The use of two sources has synergistic effect and reduces expenditure on scarce and expensive mineral fertilizers. it is a sustainable approach to ensuring high soil productivity and crop yield. Nigerian Journal of Technological Research

Study on the effects of white rice husk ash and fibrous materials additions on some properties of fiber–cement composites

This work assesses the effects of white rice husk ash (WRHA) as pozzolanic material, virgin kraft pulp (VKP), old corrugated container (OCC) and fibers derived from fiberboard (FFB) as reinforcing agents on some properties of blended cement composites. In the sample preparation, composites were manufactured using fiber-to-cement ratio of 25:75 by weight and 5% CaCl2 as accelerator. Type II Portland cement was replaced by WRHA at 0%, 25% and 50% by weight of binder. A water-to-binder ratio of 0.55 was used for all blended cement paste mixes. For parametric study, compressive strength, water absorption and density of the composite samples were evaluated. Results showed that WRHA can be applied as a pozzolanic material to cement and also improved resistance to water absorption. However, increasing the replacement level of WRHA tends to reduce the compressive strength due to the low binding ability. The optimum replacement level of WRHA in mortar was 25% by weight of binder; this replacement percentage resulted in better compressive strengths and water absorption. OCC fiber is shown to be superior to VKF and FFB fibers in increasing the compressive strength, due to its superior strength properties. As expected, the increase of the WRHA content induced the reduction of bulk density of the cement composites. Statistical analysis showed that the interaction of above-mentioned variable parameters was significant on the mechanical and physical properties at 1% confidence level.

English

A field experiment was conducted to study the effect of effective microorganisms and green manure on soil properties and yield of pearl millet (Pennisetum glaucum (L.) R. Br.) and alfalfa (Medicago sativa L.) grown on sandy loam soil under arid conditions at Agriculture Experimental Station of King Abdulaziz University (KAU), Hada Alsham, Saudi Arabia. Four treatments were investigated. In control (T1), the soil was only treated with the recommended dose of mineral fertilizers required for the cultivated crops. The second treatment (T2) was a diluted solution (1:1000) of effective microorganisms (EM1) sprayed on the soil surface. The third treatment (T3) was green manure added as soil mulch above the ground while the fourth treatment (T4) was mixture of EM1 and green manure together. Results indicated that, EM1 and green manure improved forage yield and soil properties. The best improvement in yield was found in T4 and T3 of alfalfa and pearl millet fields, respectively. These treatments resulted also in the great reduction in soil bulk density and saturated hydraulic conductivity, high water retention and soil organic matter. Total nitrogen, phosphorus, potassium, iron and magnesium were also increased under these treatments. Little enhancement in physical and chemical properties of soil was pronounced in T2 treatment since the improvements were not significant compared with the control. The results suggested that using green manure alone or mixed with EM1 is a practical method to enhance soil properties and productivity of coarse texture soils under dry land conditions.   Key words: Effective microorganisms, pearl millet, green manure, alfalfa

Dielectric Properties of Thermally Grown SiO<sub>2</sub> on 4H-SiC(0001) Substrates

The bulk properties of thermally grown SiO2 on 4H-SiC(0001) substrates were thoroughly investigated by capacitance-voltage (C-V) measurement, atomic force microscopy (AFM), spectroscopic ellipsometry (SE), x-ray photoelectron spectroscopy (XPS), and secondary ion mass spectrometry (SIMS). The equivalent oxide thickness (EOT) extracted from the capacitance-voltage (C-V) characteristics of TiN/SiO2 capacitors was proportional to the physical thickness (Tphys), but the slope of the linear fit was found to be 1.11, indicating that the permittivity of SiO2 on 4H-SiC formed by thermal oxidation is only about 3.5, which is lower than the commonly accepted value of 3.9. Since XPS analysis revealed that the oxide of SiC was stoichiometric and the atomic concentration of residual carbons in the oxide measured by SIMS was sufficiently low (1017 cm-3), the low permittivity of thermal oxides of 4H-SiC may originate from the reduced bulk density, which can be predicted by the Clausius-Mossotti relation.

Effect of Core Aerification Frequency, Area Impacted, and Topdressing Rate on Turf Quality and Soil Physical Properties

Soil compaction often occurs in heavily trafficked turf areas such as golf course putting greens and sports fields. Although research exists on benefits of proper aerification, insufficient data exists quantifying the effect of removing, or “impacting,” specific amounts of surface area per year, number of aerification events per year, or amount of topdressing applied post‐aerification on turfgrass quality and soil physical properties. Understanding these effects was the objective of this study. The study was conducted on a 10‐yr‐old U.S. Golf Association (USGA)‐specified TifEagle bermudagrass [Cynodon dactylon (L.) Pers. × C. transvaalensis Burtt Davy] research putting green to evaluate two yearly totals of percent surface area impacted, 15 and 25, summed through one, two, or three aerification events per year, with cores removed. Following aerification, treatments received one of two topdressing rates; the mathematical equivalent of soil removed with aerification or half this rate. Turf quality declined for ∼4 wk after each aerification event, at which point it typically improved. Increasing number of aerification events per year from one to three reduced bulk density (BD) between 5 and 9%, surface hardness between 5 and 19%, and thatch–mat organic matter content 10% in Year 2. Infiltration rates were highest in single aerification event treatments during the same year. Overall, increasing amount of surface area impacted and number of aerification events per year improved soil physical properties. Reducing frequency of aerification while impacting the same amount of surface area per year increased overall visual turfgrass quality while not yielding similar improvements in soil physical properties.

Effect of Dairy Manure and Rice Planting Methods on Yield, Soil Quality, Water-Use Efficiency, and Economics of Rice and Succeeding Wheat Crop

Presently, directly seeded rice (DSR) is preferred over transplanted puddle rice (TPR) because of its high water-use efficiency (WUE). Also, TPR deteriorates the soil physicochemical properties, so in these conditions dairy manure has been used to reduce bulk density, increase hydraulic conductivity, and improve soil nutrient status. Experiments were conducted to study the effects of manure and rice planting methods on yield, soil quality, WUE, and economics of rice and the succeeding wheat crop. Results showed that TPR increased kernel yield by 10.26% compared to DSR. However, it deteriorated soil physical properties and reduced soil nitrogen by 7.31% at 0–15 cm deep and nitrate concentration by 61.40% at 0–35 cm deep, which significantly reduced succeeding wheat yield by 18.21%. The residual soil organic fertility after crop harvest was proportional to the level of dairy manure used.

Reuse of waste sludge from papermaking process in cement composites

AbstractPapermaking sludge (PS), a waste residue from the pulp and paper processing, has brought great pressure on the environment because of large quantities that are produced in paper mills. This work was carried out to explore the possibility of making PS/cement composite products using solid waste of PS. Boards measuring 350 × 270 × 12 mm3 were manufactured using PS contents of 40, 50, and 60 wt%, adhesive dosages of 0, 10, and 15 wt%, and 0 and 5 wt% of calcium chloride as an accelerator. At least three replications were fabricated for each treatment, and some mechanical and physical properties of the boards were evaluated. Test results showed that the bending and internal strengths of the specimens decreased with an increase in the PS content, and the maximum values were obtained at PS loading of 40 wt%. The negative influence of PS content on the mechanical properties can be explained by the reduced bonding ability because of weaker PS compared with cement. Screw withdrawal values were up to 22.7 kPa. Water absorption and thickness swelling of cement mortar considerably increased with increased content of PS, with a corresponding reduction of bulk density. In general, all properties of the boards were improved when the adhesive and calcium chloride contents were increased. The results showed that an increase in board density improved the mechanical and physical properties. Finally, results showed that PS has good potential for recycling and utilization in developing value‐added building components. POLYM. ENG. SCI., 2013. © 2012 Society of Plastics Engineers

Repeated biodisinfection controls the incidence of Phytophthora root and crown rot of pepper while improving soil quality

Phytophthora root and crown rot is a plant disease responsible for important economic losses in protected pepper crops. A greenhouse experiment was carried out in a temperate climate region (northern Spain) to assess the effects of repeated biodisinfection after three consecutive crop seasons with different organic amendments (a non-composted mixture of sheep manure and chicken litter, a semicomposted mixture of horse manure and chicken litter, Brassica carinata dehydrated pellets plus Sinapis alba fresh green manure) on disease incidence, crop yield and soil quality. Biodisinfection treatments were found to improve soil water properties through reduction in soil bulk density and increased water infiltration. Biodisinfested soils showed higher values of physicochemical and microbial properties than control (untreated) and plastic-mulched soils. In plots treated with the non-composted or semicomposted mixture, the observed higher levels of microbial activity were strongly related with an increase in soil microbial biomass. Brassica-Sinapis treatment had a weaker effect on soil properties than animal manure-based treatments. However, highest counts of total bacteria, actinomycetes and Pseudomonas spp. were found in Brassica-Sinapis-treated soils. It was concluded that repeated biodisinfection for the control of Phytophthora root and crown rot in protected pepper crops located in temperate climate regions can improve soil quality and suppressiveness, as well as allow for a reduction in the dose of organic amendment needed for biodisinfection. Among the studied organic amendments, the semicomposted amendment was the best option in terms of reduction in disease incidence.

Deep loosening for direct drilled soil recovery

Maintaining a sustainable soil management system with annual double cropping is a considerable challenge, even when a conservation technique such as direct drilling is used. No tillage means less vehicular traffic, but not necessarily a reduction in traffic intensity because of the excessively high axles loads associated with some agricultural machines. Direct drilled soils appear to have a better recovery following agricultural traffic, but evidence has suggested that problems related to compacted layers occur in these profiles with time. Subsoiling, as a well known technique to alleviate soil compaction, has been widely quoted for tilled soils, but rather little is known about how no tilled soils respond to this technique. The task is to loosen compacted subsoil layers, with minimal disturbance of the topsoil to avoid subsequent problems during drilling. Research was performed on a fine Typic Argiudol soil managed with no tillage, annual double cropping and with and without deep loosening. Both soil treatments received the standard traffic demanded by the cropping system. Soil penetration resistance and dry bulk density were the dependant variables assessed. Results showed that although there was a major compaction tendency after traffic on loosened soil, there was also evidence that the effects of loosening persisted for almost nine months. Interestingly, it was also evident that layers below the mechanically loosened horizon exhibited a reduction in penetration resistance and bulk density. It was concluded that periodic subsoiling can alleviate the soil compaction caused by agricultural traffic in deep soil layers and will allow direct drilling to continue sustainably. Subsoiling not only alleviates compaction in the mechanically disturbed layers, but also in the horizon immediately below.

Re-Pulped Waste Paper-Based Composite Building Materials with Low Thermal Conductivity

This paper presents an investigation on the properties and applications of paper-based composites. The materials composed of cement, sand and re-pulped waste paper. The physical, mechanical and thermal properties of various types of paper composites were determined. The results showed that the addition of re-pulped waste paper causes high water absorption and leads to a reduction in thermal conductivity, bulk density and compressive strength. Sample mixtures containing re-pulped newspaper, office paper or any type of mixed paper have similar property values. The one exception was samples made from re-pulped carton paper which had a lower thermal conductivity and a lower bulk density than the others. When the proposed blocks were manufactured for comparison with existing masonry blocks, they were shown to satisfy the basic requirements of affordable insulating building materials and to support energy-saving and environmental conservation goals.