Physical Properties Including Bulk Density Research Articles

Smart Computing Techniques for Predicting Soil Compaction Criteria under Realistic Field Conditions

The primary objective of this paper was to develop an artificial neural network (ANN) simulation environment and mathematical models for predicting with high accuracy soil compression parameters. The experiments were conducted at the College of Agriculture - University of Basra, located at Garmat Ali, the soil was silty clay loam. The factors that were investigated are moisture content (14 and 24%), tillage depths (0, 15, 30, 45, and 50 cm) forward speeds (0.57, 0.94, and 1.34 m.s-1) and tire pressures (50, 100, and 150 kPa). ANN environment was developed with the back propagation algorithm using MATLAB software with various structures and training algorithms. Design Expert software utilized to evaluate the studied parameters and produce mathematical models. The results showed that all studied parameters had a significant effect on soil physical properties including bulk density and cone index. The effects of the studied factors on bulk density were depth > moisture content > forward speed, > tire pressure (6% 4%, 2.4%, 2%, respectively). Whereas, the order of the investigated factors based on their effects on cone index were depth > moisture content > tire pressure > forward speed (6%, 4%, 2.4% and 2%, respectively). The best model for predicting the bulk density under different field conditions was the 4-8-1 architecture. Levenberg-Marquardt (Trainlm) produced outstanding performance with an MSE of 0.00226 and R2 of 0.986. Moreover, this performance was occurring at an epoch of 100. For predicting cone index, the best performance was achieved by Levenberg-Marquardt (trainlm) in 85 epochs, giving minimum MSE equal to 0.005112 and greater (R2) equal to 0.967 during the training process. Thus, the optimal structure for predicting cone index was 4-7-1.

Critique of USGA Reco mmendations for A Method of Putting Green Construction

The United States Golf Association (USGA) originally published specifications for greens construction in a 1960 five-page publication. The document was designed as a guide to golf course builders to ensure greens would provide good playing conditions for many years, and is based on research from the Green Section, UCLA, and Texas A & M College. Reco mmendations from this document were designed to provide a green with sufficient drainage and resistance to compaction, a combination difficult to achieve without a degree of compromise. Since this release, the original reco mmendations have been updated four times, most recently in 2018. The document gives guidance on a range of soil physical properties including bulk density, porosity, saturated hydraulic conductivity, grain size distribution, bridging factors, and amendments. The most recent version of the specifications builds on previous versions; however, some reco mmendations warrant further examination such as the statement that addition of small amounts of soil to a rootzone mix will likely reduce the infiltration rate without a significant increase in water retention.

Trade-off between soil pH, bulk density and other soil physical properties under global no-tillage agriculture

No-tillage (NT), here defined as NT with/without residue retention, has been widely used as a sustainable alternative to conventional tillage (CT). In particular, site-specific effects of NT on the soil pH, and soil physical properties including bulk density, total porosity, aggregate size and stability, hydraulic property, available water capacity have been intensively studied within various agroecosystems in the past decades. However, the synthesis of information on a global scale remains lacking. Here, using a global dataset based on 264 publications, effects of agronomic/environmental factors on soil physical properties under NT were quantified by intensive meta-analysis. We found that the effects of NT on soil physical properties are fairly complex, and greatly depend on climate conditions, experimental duration, and soil texture. Specifically, relative to CT, NT increased soil bulk density by 2.3%. Soil bulk density increased by 3.7% during the first 6 years of NT. Meanwhile, NT increased soil penetration resistance by 27.8%; NT decreased soil pH by 1.8%, the greatest reduction took place in silty soils (5.6%) or during a moderate-term NT (6–12 years, 5.0%). Nonetheless, regardless of environmental and agronomic factors, NT improved mean weight diameter and water-stable aggregate by 50 and 36%, respectively. Although NT had no effects on the saturated hydraulic conductivity, it enhanced soil available water capacity by 8.7%. Taken altogether, the trade-offs between observed negative effects such as increased bulk density and decreased soil pH; and positive effects such as improved aggregate size and stability, and soil water availability demonstrate the overall beneficial responses on soil physical property under global NT agriculture. Furthermore, the present study demonstrated that climate conditions (e.g. mean annual precipitation and temperature), and experimental duration appeared to be the predominant factors controlling the response of soil properties to NT application. These results will help design site-specific NT management strategies considering highly informative, and prevalent environmental and agronomic factors within a local environment.

Thirty-four years of no-tillage and cover crops improve soil quality and increase cotton yield in Alfisols, Southeastern USA

In subhumid Southeastern USA, rapid decomposition of initially low cotton residue limits the benefits of no-tillage system in regard to the soil quality. Long-term addition of cover crops may compensate the low cotton residue and further improve the soil physical quality under no-tillage system. We examined the long-term (34 yr) effect of two cover crop species, hairy vetch (Vicia villosa), and winter wheat (Triticum aestivum L.), and no cover crop, applied on conventional tillage and no-tillage on soil hydro-physical properties and cotton yield. Research was conducted on a Lexington silt loam in Jackson, TN, during 2015 and 2016. Soil physical properties including bulk density, cone penetration resistance, in-situ soil moisture content, wet aggregate stability, water infiltration and field-saturated hydraulic conductivity, soil water retention characteristics, and dry aggregate size distribution were measured. Bulk density assessed before the annual tillage did not differ significantly between no-tillage and conventional tillage systems. Cone penetration resistance showed a greater horizontal consistency of maximally resistant zones (>2 MPa) under tilled managements, indicating a possible presence of a plow pan immediately below the plowed soil layer. Differences in field soil moisture content among tillage and cover crops were more evident in drier periods of the growing seasons, resulting in 28.6% and 36.4% greater moisture content in vetch cover crop and no-tillage than no cover crop and conventional tillage, respectively. No-tillage and vetch cover crop also increased the wet aggregate stability by 13% at 0–15 cm. Results showed a significant tillage × cover crop interaction in soil hydraulic properties. Our result demonstrates that long-term incorporation of cover crops, particularly vetch with no-tillage, significantly improved the initial infiltration rate, cumulative infiltration, and field-saturated hydraulic conductivity and increased the mean weight diameter of aggregates by promoting the macroaggregation. Improvement in soil physical properties was associated with an increase in cotton lint yield under cover crop and no-tillage management.

Comparing the infiltration potentials of soils beneath the canopies of two contrasting urban tree species

With ongoing urbanization and climate change our cities are continuously becoming warmer and susceptible to flash flooding. A wide array of green infrastructure including urban trees is getting attention to mitigate those problems; however, magnitude, patterns and processes of hydrological functional capacity of different tree species at micro-scales are largely unknown. We measured morphology, above and below ground growth of two ecologically contrasting street tree species at two streets in Munich, Germany: Robinia pseudoacacia L. and Tilia cordata Mill. during 2016-17. Additionally, tree transpiration, meteorological and edaphic variables including soil hydraulic conductivity was measured on two streets. Overall the soil physical properties including bulk density, particle size distribution and meteorological variables were not significantly different at the two sites. A higher soil infiltration rate (0.42 cm/min) under the canopies of R. pseudoacacia compared to the T. cordata (0.29 cm/min) was mainly attributed to the higher annual growth rate of R. pseudoacacia and showed a significant correlation (r = 0.62) with infiltration rate. Subsequently, R. pseudoacacia showed increased fine root biomass compared to T. cordata (121 g/m2 and 27 g/m2 respectively). However, T. cordata trees transpired three times more compared to R. pseudoacacia which indicated that they might have a deeper rooting system. The study showed that fast growing species such as R. pseudoacacia can enhance infiltration through its intense fine rooting system creating channels in the upper soil. Moreover, grass cover also plays a role both in infiltration and ground evapotranspiration compared to the built surfaces and can enhance the processes if planted in combination with less water using species. Secondly, higher root biomass and infiltration further away from the tree trunk suggest a need for larger tree planting pits whereas species such as T. cordata are better suited in paved cut-out pits inducing vertical rooting depth.

Effect of Moldboard Plow Types on Soil Physical Properties Under Different Soil Moisture Content and Tractor Speed

An experiment was conducted in fields of Agriculture college, University of Basrah. The experiment was designed with split-spilt plots in Complete Randomized Blocks Design Treatments included three types of moldboard plows: helical, semi digger and general –purpose, three soil moisture content levels (10.23,16.47 and 24.68%), and four tractor speed of 0.41, 0.56, 0.86 and 1.21 m sec -1 . The soil physical properties were determined after plowing soil by using three types of moldboard plow. The results showed that there was significant effect of moldboard plow types, soil moisture content and tractor speed on soil physical properties including bulk density, soil porosity, soil penetration resistance and pulverization ratio. Results also indicated that the effect of interaction among plow types, soil moisture content and tractor speed was significantly on soil penetration resistance and pulverization ratios while it had not significantly effect on bulk density, soil porosity. In general, soil physical properties, had been improved when using high tractor speed and moderate soil moisture content whereas optimal operation was obtained when using general-purpose plow type and high tractor speed of 1.12 m sec -1 and soil moisture content of 16.47% where this combination gives low bulk density (0.96Mg m-3), high soil porosity (63.90%) high soil pulverization ratio (74%) and low soil penetration resistance (623.47 kN m-2).

Acoustics of biologically active marine sediments

Biological organisms are prevalent on and near the seabed; however, most predictive theoretical models do not explicitly address the acoustic behavior of biologically active marine sediments. Sediment-acoustics models, such as those based on Biot theory or grain-shearing theory, allow for parameterization of various physical properties including bulk density, porosity, shear strength, or pore fluid viscosity, all of which can be modified by the presence of biological organisms or bioturbation. Other models can include the effects gas bubble distributions, which can also be associated with the presence of benthic biology, on compressional and shear wave propagation. In this paper, we examine sediment-acoustics models in comparison with data from various field experiments focused on infauna- and seagrass-bearing sediments. The model parameters are partially constrained by physical data from core samples collected at the field experiment sites. Empirical relations between the core data parameters and acoustic data will also be examined. [Work supported by ONR and ARL:UT IR&D.]

Effect of Moldboard Plow Types on Soil Physical Properties Under Different Soil Moisture Content and Tractor Speed

An experiment was conducted in fields of Agriculture college, University of Basrah. The experiment was designed with split-spilt plots in Complete Randomized Blocks Design Treatments included three types of moldboard plows: helical, semi digger and general –purpose, three soil moisture content levels (10.23,16.47 and 24.68%), and four tractor speed of 0.41, 0.56, 0.86 and 1.21 m sec -1 . The soil physical properties were determined after plowing soil by using three types of moldboard plow. The results showed that there was significant effect of moldboard plow types, soil moisture content and tractor speed on soil physical properties including bulk density, soil porosity, soil penetration resistance and pulverization ratio. Results also indicated that the effect of interaction among plow types, soil moisture content and tractor speed was significantly on soil penetration resistance and pulverization ratios while it had not significantly effect on bulk density, soil porosity. In general, soil physical properties, had been improved when using high tractor speed and moderate soil moisture content whereas optimal operation was obtained when using general-purpose plow type and high tractor speed of 1.12 m sec -1 and soil moisture content of 16.47% where this combination gives low bulk density (0.96Mg m-3), high soil porosity (63.90%) high soil pulverization ratio (74%) and low soil penetration resistance (623.47 kN m-2).

Ecological impacts of long-term application of biosolids to a radiata pine plantation

Assessment of the ecological impact of applying biosolids is important for determining both the risks and benefits. This study investigated the impact on soil physical, chemical and biological properties, tree nutrition and growth of long-term biosolids applications to a radiata pine (Pinus radiata D. Don) plantation growing on a Sandy Raw Soil in New Zealand. Biosolids were applied to the trial site every 3years from tree age 6 to 19years at three application rates: 0 (Control), 300 (Standard) and 600 (High) kg nitrogen (N) ha−1, equivalent to 0, 3 and 6Mg ha−1 of dry biosolids, respectively. Tree nutrition status and growth have been monitored annually. Soil samples were collected 13years after the first biosolids application to assess the soil properties and functioning. Both the Standard and High biosolids treatments significantly increased soil (0–50cm depth) total carbon (C), N, and phosphorus (P), Olsen P and cation exchange capacity (CEC), reduced soil pH, but had no significant effects on soil (0–20cm depth) physical properties including bulk density, total porosity and unsaturated hydraulic conductivity. The High biosolids treatment also increased concentrations of soil total cadmium (Cd), chromium (Cr), copper (Cu) and lead (Pb) at 25–50cm depth, but these concentrations were still considered very low for a soil. Ecotoxicological assessment showed no significant adverse effects of biosolids application on either the reproduction of springtails (Folsomia candida) or substrate utilisation ability of the soil microbial community, indicating no negative ecological impact of bisolids-derived heavy metals or triclosan. This study demonstrated that repeated application of biosolids to a plantation forest on a poor sandy soil could significantly improve soil fertility, tree nutrition and pine productivity. However, the long-term fate of biosolids-derived N, P and litter-retained heavy metals needs to be further monitored in the receiving environment.

A comparison of the efficacy and ecosystem impact of residual-based and topsoil-based amendments for restoring historic mine tailings in the Tri-State mining district

A long-term research and demonstration site was established on Pb and Zn mine wastes in southwestern Missouri in 1999. Municipal biosolids and lime and composts were mixed into the wastes at different loading rates. The site was monitored intensively after establishment and again in 2012. A site restored with topsoil was also included in the 2012 sampling. Initial results including plant, earthworm and small mammal assays indicate that the bioaccessibility of metals had been significantly reduced as a result of amendment addition. The recent sampling showed that at higher loading rates, the residual mixtures have maintained a vegetative cover and are similar to the topsoil treatment based on nutrient availability and cycling and soil physical properties including bulk density and water holding capacity. The ecosystem implications of restoration with residuals versus mined topsoil were evaluated. Harvesting topsoil from nearby farms would require 1875years to replace based on natural rates of soil formation. In contrast, diverting biosolids from combustion facilities (60% of biosolids generated in Missouri are incinerated) would result in greenhouse gas savings of close to 400Mg CO2 per ha.

Fluidized Bed Drying of Sprouted Wheat(Triticum aestivum)

Abstract Wheat is a staple food throughout the world. Sprouted wheat contains numerous vitamins, secondary plant ingredients, enzymes, mineral nutrients and trace materials. The present work was carried on drying of sprouted wheat (Triticum aestvum) in a laboratory fluidized bed using different operating conditions. Physical properties including bulk density, tapped density, particle density and porosity were determined for various forms of wheat. The proximate analysis and handling properties were measured. The entire drying period was considered to follow falling rate period. The experimental data were modeled using Fick’s diffusion equation and the effective diffusivity coefficients were found to be within the range of 7.3 × 10–10 to 30.4 × 10–10 m2/s. Malting caused significant increase in protein content. During drying lightness increased, while yellowness and redness decreased. The dehydrated sprouted wheat exhibited excellent reconstitution andkeeping quality. The dehydrated sprouted wheat flour can be used for making noodles, pasta, laddu, bread, unleavened bread, porridge and gruels for newborns.

Effects of Grazing Sorghum Stubble on Soil Physical Properties and Subsequent Crop Performance

Two grazing trials were conducted on a Vertosol in central Queensland to assess the effects of stubble grazing by cattle on soil properties and subsequent crop performance. Two adjacent contour bays were selected for two treatments (grazed and ungrazed) in each trial. Both trials were conducted following a grain sorghum crop. In trial 1 (during 1996) the surface soil was dry throughout grazing. In trial 2 (during 1998) the surface soil became saturated during grazing after 125 mm of rain. Soil physical properties including bulk density, shear strength, cone index and hydraulic conductivity were measured pre-and post-grazing in both trials and the response of wheat crops sown after grazing was assessed. The area was then double-cropped to sorghum to measure any further residual impacts. After grazing on dry soil, hoof marks were barely evident and no significant change was found in any soil physical property or the establishment or yield of a subsequent wheat crop. After grazing on saturated soil, there were visible hoof marks 49 mm deep and increases in soil shear strength, cone index and drawbar power requirement. The following wheat crop had reduced dry matter at 32 days and reduced grain yield. There was no immediate change in ground cover and no effect on wheat establishment following direct-drilling 37 days after the cattle were removed. In a sorghum crop following the wheat crop, there were no carryover effects on any soil physical property or on crop yield. We conclude that under a similar regime to that of trial 1 (dry soil and no rainfall during grazing), adverse effects of stubble grazing are unlikely. It follows that if grazing can be restricted to times when the surface soil is dry enough to minimise compaction by animals, there is little risk of adverse effects on subsequent crop performance.