scholarly journals Joint Rapid Airfield Construction (JRAC) Program 2004 Demonstration Project--Fort Bragg, North Carolina

2021 ◽  
Author(s):  
Gary Anderton ◽  
Ernest Berney ◽  
John Newman ◽  
Travis Mann ◽  
Chad Gartrell ◽  
...  
Keyword(s):  
Soil Surface ◽  
Water Infiltration ◽  
Flight Crew ◽  
Soil System ◽  
Landing Zone ◽  
Rapid Construction ◽  
Stabilized Soil ◽  
Fort Bragg ◽  
The Stability ◽  
Polymer Stabilized

This report describes the demonstration of technologies and procedures developed during April 2002 and May 2004 under the Joint Rapid Airfield Construction (JRAC) Program. The demonstration took place at Sicily Landing Zone (LZ) at Fort Bragg, NC, in July of 2004. The objective of the exercise was to demonstrate the procedures and technologies developed under the JRAC Program by rapidly building two parking aprons capable of supporting C-130 transport aircraft taxiing and parking operations. The exercise was conducted under continuous 24-hr operations to simulate a real-world rapid construction environment. Apron 1 (north apron) was constructed using two technologies, one-half being ACE™ Matting and the other half being a cement-polymer stabilized soil surface. Apron 2 (south apron) was constructed solely of a fiber-cement-stabilized soil system. Both aprons were treated with a polymer emulsion surface application to form a sealed surface against abrasion and water infiltration. The entire construction of both aprons required 76 hr, with Apron 1 finished in 48 hr. The construction of Apron 1 was validated by operation of a C-130 aircraft approximately 31 hr after completion with success and high praises from the aircraft flight crew on the stability and surface of the apron, as well as its dust-abating characteristics.

scholarly journals A Strip-Till One-Pass System as a Component of Conservation Agriculture

Agronomy ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 2015
Author(s):  
Iwona Jaskulska ◽  
Kestutis Romaneckas ◽  
Dariusz Jaskulski ◽  
Piotr Wojewódzki
Keyword(s):  
Co2 Emissions ◽  
Soil Loss ◽  
Soil Surface ◽  
Conservation Agriculture ◽  
Plant Residues ◽  
Pass System ◽  
Previous Crop ◽  
Bacteria And Fungi ◽  
The Stability ◽  
The Impact

Conservation agriculture has three main pillars, i.e., minimum tillage, permanent soil cover, and crop rotation. Covering the soil surface with plant residues and minimum mechanical soil disturbance can all result from introducing a strip-till one-pass (ST-OP) system. The aim of this study was to determine the impact of the ST-OP technology on the management of plant residues, soil properties, inputs, and emissions related to crop cultivation. We compared the effect of a ST-OP system against conventional tillage (CT) using a plough, and against reduced, non-ploughing tillage (RT). Four field experiments were conducted for evaluating the covering of soil with plant residues of the previous crop, soil loss on a slope exposed to surface soil runoff, soil structure and aggregate stability, occurrence of soil organisms and glomalin content, soil moisture and soil water reserve during plant sowing, labour and fuel inputs, and CO2 emissions. After sowing plants using ST-OP, 62.7–82.0% of plant residues remained on the soil surface, depending on the previous crop and row spacing. As compared with CT, the ST-OP system increased the stability of soil aggregates of 0.25–2.0 mm diameter by 12.7%, glomalin content by 0.08 g·kg−1, weight of earthworms five-fold, bacteria and fungi counts, and moisture content in the soil; meanwhile, it decreased soil loss by 2.57–6.36 t·ha−1 year−1, labour input by 114–152 min·ha−1, fuel consumption by 35.9–45.8 l·ha−1, and CO2 emissions by 98.7–125.9 kg·ha−1. Significant favourable changes, as compared with reduced tillage (RT), were also found with respect to the stability index of aggregates of 2.0–10.0 mm diameter, the number and weight of earthworms, as well as bacteria and fungi counts.

scholarly journals Optimal profile for concave slopes under static and seismic conditions

2016 ◽  
Vol 53 (9) ◽  
pp. 1522-1532 ◽  
Author(s):  
Farshid Vahedifard ◽  
Shahriar Shahrokhabadi ◽  
Dov Leshchinsky
Keyword(s):  
Limit Equilibrium ◽  
Stable Configuration ◽  
Preliminary Evaluation ◽  
Construction Technology ◽  
Stability Of Slopes ◽  
Optimal Profile ◽  
Stabilized Soil ◽  
The Stability ◽  
Comparison Of The Results ◽  
The Impact

This study presents a methodology to determine the stability and optimal profile for slopes with concave cross section under static and seismic conditions. Concave profiles are observed in some natural slopes suggesting that such geometry is a more stable configuration. In this study, the profile of a concave slope was idealized by a circular arc defined by a single variable, the mid-chord offset (MCO). The proposed concave profile formulation was incorporated into a limit equilibrium–based log spiral slope stability method. Stability charts are presented to show the stability number, MCO, and mode of failure for homogeneous slopes corresponding to the most stable configuration under static and pseudostatic conditions. It is shown that concave profiles can significantly improve the stability of slopes. Under seismic conditions, the impact of concavity is most pronounced. Good agreement was demonstrated upon comparison of the results from the proposed method against those attended from a rigorous upper bound limit analysis. The proposed methodology, along with recent advances in construction technology, can be employed to use concave profiles in trenches, open mine excavations, earth retaining systems, and naturally cemented and stabilized soil slopes. The results presented provide a useful tool for preliminary evaluation for adopting such concave profiles in practice.

scholarly journals INFLUÊNCIA DA COMPACTAÇÃO E DO CULTIVO DE SOJA NOS ATRIBUTOS FÍSICOS E NA CONDUTIVIDADE HIDRÁULICA EM LATOSSOLO VERMELHO

Irriga ◽  
2003 ◽  
Vol 8 (3) ◽  
pp. 242-249 ◽  
Author(s):  
Amauri Nelson Beutler ◽  
José Frederico Centurion ◽  
Cassiano Garcia Roque ◽  
Zigomar Menezes de Souza
Keyword(s):  
Hydraulic Conductivity ◽  
Bulk Density ◽  
Soil Compaction ◽  
Soil Surface ◽  
Total Porosity ◽  
Soil Condition ◽  
Agricultural Science ◽  
Water Infiltration ◽  
Loose Soil ◽  
Physical Attributes

INFLUÊNCIA DA COMPACTAÇÃO E DO CULTIVO DE SOJA NOS ATRIBUTOS FÍSICOS E NA CONDUTIVIDADE HIDRÁULICA EM LATOSSOLO VERMELHO   Amauri Nelson BeutlerJosé Frederico CenturionCassiano Garcia RoqueZigomar Menezes de SouzaDepartamento de Solos e Adubos, Faculdade de Ciências Agrárias e Veterinárias, Universidade Estadual Paulista, Jaboticabal, SP. CEP 14870-000. E-mail: [email protected], [email protected]  1 RESUMO              Este estudo teve como objetivo determinar a influência da compactação e do cultivo de soja nos atributos físicos e na condutividade hidráulica de um Latossolo Vermelho de textura média. O experimento foi conduzido na Universidade Estadual Paulista – Faculdade de Ciências Agrárias e Veterinárias, Jaboticabal (SP). Os tratamentos foram: 0, 1, 2, 4 e 6 passadas de um trator, uma ao lado da outra perfazendo toda a superfície do solo, com quatro repetições. O delineamento experimental foi inteiramente casualizado para a condutividade hidráulica e, em esquema fatorial 5 x 2 para os atributos físicos. Foram coletadas amostras de solo nas faixas de profundidades de 0,02-0,05; 0,07-0,10 e 0,15-0,18 m, por ocasião da semeadura e após a colheita para determinação da densidade do solo, porosidade total, macro e microporosidade do solo. A condutividade hidráulica do solo foi determinada após a colheita. O tempo entre a semeadura e a colheita de soja foi suficiente para aumentar a compactação do solo apenas na condição de solo solto. A compactação do solo reduziu a condutividade hidráulica em relação a condição natural (mata) e a condição de solo solto, sendo que esta não foi reduzida, após a primeira passagem, com o aumento no número de passagens.  UNITERMOS: Densidade do solo, porosidade do solo, infiltração de água, soja.  BEUTLER, A. N.; CENTURION, J. F.; ROQUE, C. G.; SOUZA, Z. M. COMPACTION AND SOYBEAN GROW INFLUENCE ON PHYSICAL ATTRIBUTES AND  HYDRAULIC CONDUCTIVITY IN RED LATOSSOL SOIL   2 ABSTRACT  The purpose of this study was to determine the influence of compaction and soybean grow on physical attributes and hydraulic conductivity of a Red Latossol, medium texture soil. The experiment was carried out in the experimental farm at the Paulista State University  – Agricultural Science College, Jaboticabal – São Paulo state. The treatments were 0, 1, 2, 4 and 6 side-by-side tractor strides on the soil surface with four replications. The experimental design was completely randomized for hydraulic conductivity and a 5 x 2 factorial design for soil physical attributes. Soil samples have been collected at 0.02-0.05, 0.07-0.10 and 0.15-0.18 m depth at sowing season and after harvest in order to determine soil bulk density, total porosity, macro and micro porosity. Soil hydraulic conductivity was determined after harvest. The time period between the soybean sowing and harvesting was enough to increase soil compaction only in loose soil condition. Soil compaction reduced hydraulic conductivity compared to the natural (forest) and loose soil condition  KEYWORDS: Bulk density, soil porosity, water infiltration, soybean.

scholarly journals Water repellency of clay, sand and organic soils in Finland

2008 ◽  
Vol 16 (3) ◽  
pp. 267 ◽  
Author(s):  
K. RASA ◽  
R. HORN ◽  
M. RÄTY
Keyword(s):  
Preferential Flow ◽  
Management Practice ◽  
Soil Surface ◽  
Water Repellency ◽  
Organic Soil ◽  
Water Infiltration ◽  
Organic Soils ◽  
Water Repellent ◽  
Moisture Regime ◽  
Wetting Process

Water repellency (WR) delays soil wetting process, increases preferential flow and may give rise to surface runoff and consequent erosion. WR is commonly recognized in the soils of warm and temperate climates. To explore the occurrence of WR in soils in Finland, soil R index was studied on 12 sites of different soil types. The effects of soil management practice, vegetation age, soil moisture and drying temperature on WR were studied by a mini-infiltrometer with samples from depths of 0-5 and 5-10 cm. All studied sites exhibited WR (R index >1.95) at the time of sampling. WR increased as follows: sand (R = 1.8-5.0) < clay (R = 2.4-10.3) < organic (R = 7.9-undefined). At clay and sand, WR was generally higher at the soil surface and at the older sites (14 yr.), where organic matter is accumulated. Below 41 vol. % water content these mineral soils were water repellent whereas organic soil exhibited WR even at saturation. These results show that soil WR also reduces water infiltration at the prevalent field moisture regime in the soils of boreal climate. The ageing of vegetation increases WR and on the other hand, cultivation reduces or hinders the development of WR.;

Characteristic on the Stability of Haloxylon Ammodendron Plantation in the Southern Fringe of Gurbantunggut Desert, Northwest China

2021 ◽  
Author(s):  
Qinghong Luo ◽  
Qimin Chen ◽  
Miao He ◽  
Na Li
Keyword(s):  
Northwest China ◽  
Gurbantunggut Desert ◽  
Haloxylon Ammodendron ◽  
Coordinated Development ◽  
Soil System ◽  
Management Measures ◽  
Gurbantünggüt Desert ◽  
The Stability ◽  
Southern Fringe ◽  
System Coupling

Using chronosequence theory and method, the characteristics of vegetation-soil coupling and structure stability of Haloxylon ammodendron plantations in the southern fringe of Gurbantunggut Desert were analyzed. The results showed, the canopy storey of H. ammodendron plantation experienced three stages, rapid growth (the age of 7 to 20), then slow growth (the age of 20 to 28) and last decline (over the age of 28). The best natural regeneration started from 17-yr-old plantation. Vegetation-soil system coupling degree (C) and coupling coordinative degree (D) of plantations with different age were not one-to-one correspondence. The system of H. ammodendron plantations always stayed in disorder recession, vegetation and soil were prone to loss type during the process of sand-fixation. Five principal components evaluated that the first rank was 42-yr-old plantation. It was inferred that the trend of the vegetation and soil system was from senescence to harmonious development. So the trend of coordinated development between vegetation and soil would be promoted, if the artificial tending and management measures strengthened.

scholarly journals Linking Termite Feeding Preferences and Soil Physical Functioning in Southern-Indian Woodlands

Insects ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 4 ◽  
Author(s):  
Sougueh Cheik ◽  
Rashmi Ramesh Shanbhag ◽  
Ajay Harit ◽  
Nicolas Bottinelli ◽  
Raman Sukumar ◽  
...  
Keyword(s):  
Hydraulic Conductivity ◽  
Deciduous Forest ◽  
Soil Surface ◽  
Soil Bulk Density ◽  
Water Infiltration ◽  
Arid Environments ◽  
Feeding Preferences ◽  
Soil Hydraulic Conductivity ◽  
Odontotermes Obesus ◽  
Soil Hydraulic

Termites are undoubtedly amongst the most important soil macroinvertebrate decomposers in semi-arid environments in India. However, in this specific type of environment, the influence of termite foraging activity on soil functioning remains unexplored. Therefore, this study examines the link between the quality of litter and the functional impact of termite feeding preferences on soil properties and soil hydraulic conductivity in a deciduous forest in southern India. Different organic resources (elephant dung: “ED”, elephant grass: “EG”, acacia leaves: “AL” and layers of cardboard: “CB”) were applied on repacked soil cores. ED appeared to be the most attractive resource to Odontotermes obesus, leading to a larger amount of soil sheeting (i.e., the soil used by termites for covering the litter they consume), more numerous and larger holes in the ground and a lower soil bulk density. As a consequence, ED increased the soil hydraulic conductivity (4-fold) compared with the control soil. Thus, this study highlights that the more O. obesus prefers a substrate, the more this species impacts soil dynamics and water infiltration in the soil. This study also shows that ED can be used as an efficient substrate for accelerating the infiltration of water in southern-Indian soils, mainly through the production of galleries that are open on the soil surface, offering new perspectives on termite management in this environment.

Evaluation of the potential to dispose of sewage-sludge. 1. Soil hydraulic and overland-flow properties of Pinus plantations in Queensland

Soil Research ◽  
1995 ◽  
Vol 33 (6) ◽  
pp. 1041 ◽  
Author(s):  
A Costantini ◽  
RJ Loch ◽  
SF Glanville ◽  
DN Orange
Keyword(s):  
Sewage Sludge ◽  
Ground Water ◽  
Overland Flow ◽  
Water Movement ◽  
Soil Surface ◽  
Water Infiltration ◽  
Podzolic Soils ◽  
Antecedent Conditions ◽  
Ground Water Pollution ◽  
Sludge Application

The studies reported in this paper were designed to evaluate the potential for disposal of sewage sludge in commercial Pinus plantations at Beerburrum, 50 km north of Brisbane. Soil descriptions and measurements of hydraulic properties were made in three soils, covering the range of perceived site suitability for sludge application. Disc permeameters and a rainfall simulator were used to characterize surface infiltration properties both with and without sludge, and ponded rings were used to assess permeability of the upper B horizon. Although surface hydraulic conductivities were potentially high, infiltration into dry soil was reduced by water repellence associated with fungal matting at the soil surface and mycelia extending through the Al horizon. Surface runoff could be generated from dry soils by relatively low intensity rainfall events, and the rate and volume of runoff was not increased by broadcast sludge application. Hydraulic conductivities of the upper Bt horizons in the lateritic and yellow podzolic soils were high, suggesting that persistent perched watertable development was unlikely. However, the presence of bleached A2 horizons and gleyed Bt horizons with prominent mottling in these soils were interpreted as evidence of periodic regional ground-water intrusion. By contrast, hydraulic conductivity in the Bt horizon of the soloth was low, suggesting that locally restricted drainage occurs. Likely pathways of water movement were inferred for three representative soil types in the proposed sludge application project. There is potential for both Hortonian runoff when antecedent conditions are dry, and saturated runoff during prolonged wet periods. Potential off-site pollution could therefore occur if either solids or solutes from the sludge are susceptible to transport. In addition, preferential how paths of water infiltration were demonstrated, and the potential for accelerated water and solute movement to ground watertables was inferred. The studies reported in this, and the second, paper in the series were used to appraise the potential for either surface water or ground water pollution from land-based sludge disposal.

scholarly journals Soil Functional Responses to Natural Ecosystem Restoration of a Pine Forest Peucedano-Pinetum after a Fire

Forests ◽  
2020 ◽  
Vol 11 (3) ◽  
pp. 286 ◽  
Author(s):  
Edyta Hewelke ◽  
Ewa Beata Górska ◽  
Dariusz Gozdowski ◽  
Marian Korc ◽  
Izabella Olejniczak ◽  
...  
Keyword(s):  
Forest Fires ◽  
Soil Depth ◽  
Water Drop ◽  
Soil Microbial Communities ◽  
Internal Transcribed Spacers ◽  
Water Infiltration ◽  
Species Structure ◽  
Natural Ecosystem ◽  
Functional Responses ◽  
Soil System

Progressing climate change increases the frequency of droughts and the risk of the occurrence of forest fires with an increasing range and a dramatic course. The availability of water and its movement within an ecosystem is a fundamental control of biological activity and physical properties, influencing many climatic processes, whereas soil water repellency (SWR) is a key phenomenon affecting water infiltration into the soil system. Focusing on wide-spectrum effects of fire on the soil system, the research was conducted on a pine stand (Peucedano-Pinetum W. Mat. (1962) 1973) in Kampinos National Park located in central Poland, affected by severe and weak fires, as well as control plots. The main aim of the study was to examine the regeneration of the ecosystem 28 months after the occurrence of a fire. The effect of SWR and soil moisture content, total organic carbon, nitrogen and pH, and gain an understanding of the environmental conditions and processes that shaped the evolution of the species structure of soil microorganism communities (fungal vs. bacterial) have been examined. The Water Drop Penetration Time (WDPT) test was used to assess spatial variability of SWR in 28 plots. Soil bacterial and fungal communities were analysed by Illumina’MISeq using 16S rRNA and Internal Transcribed Spacers 1 (ITS1) regions in six selected plots. After a relatively wet summer, elevated hydrophobicity occurred in areas affected by a weak fire as much as 20 cm into the soil depth. The severe fire and subsequent increase in the richness of the succession of non-forest species contributed to the elimination of hydrophobicity. SWR was more closely linked to the structure and diversity of soil microbial communities than soil physicochemical properties that took place in response to the fire. A statistically significant relationship between the relative occurrence of microorganisms (≥ 1.0% in at least one of the samples) and SWR was established for the following fungi and bacteria species: Archaeorhizomyces sp., Leotiomycetes sp., Byssonectria fusispora, Russula vesca, Geminibasidium sp., family Isosphaeraceae and Cyanobacteria (class 4C0d-2, order MLE1-12). Insight into the functional roles of the individual identified microbial taxa that may be responsible for the occurrence of hydrophobicity was also presented.

Finite Element Analysis to Vibratory Drum - Soil Model of Vibratory Roller

2011 ◽  
Vol 94-96 ◽  
pp. 2005-2008 ◽  
Author(s):  
Yuan Wen Cao ◽  
Xue Jiao Huang ◽  
Li Ying Ma ◽  
Sheng Qiu ◽  
Shao Xiong Gui
Keyword(s):  
Finite Element ◽  
Longitudinal Vibration ◽  
Soil Surface ◽  
Element Model ◽  
Element Analysis ◽  
Soil System ◽  
Linear Character ◽  
Finite Element Software ◽  
Vibration Compaction ◽  
The Finite Element Model

In this paper a dynamical equation about vibratory drum - soil system was set based on the non-linear character of vibration compaction of vibratory roller. The finite element model of vibratory drum - soil system was established by the finite element software ABAQUS, with which the vibration compaction process of vibratory drum is simulated. According to the analysis of the vibration propagation on the soil surface, the longitudinal vibration propagation of soil, the stress and strain of the soil under the vibratory drum, results have proved that it is valid to simulate the interaction between vibratory drum and soil by the nonlinear finite element method, which offered a new way to research the interaction between vibratory drum and soil.

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