نتایج جستجو برای: sand layered soil
تعداد نتایج: 237372 فیلتر نتایج به سال:
We examined the transport properties of graphene oxide nanoparticles (GONPs) in saturated sandy soil, under different solution chemistry conditions and flow velocities. GONPs exhibited high mobility in soil, even at 50 mM NaCl. While at relatively high ionic strength GONPs were less mobile in soil than in quartz sand, the differences were not significant. At a concentration of 0.5 mM, Ca(2+) si...
Biological processes may provide great and previously unexplored opportunities for cost-effective, in situ improvement of the engineering properties of soil. A laboratory study was conducted to evaluate the changes in geomechanical properties of sand attributable to the formation of calcium precipitates induced through ureolysis catalyzed by Sporosarcina pasteurii (S. pasteurii). Specifically, ...
This study was done to evaluate the effect of afforestation in sand dunes at the vicinity of Shush, because of the importance of soil protection and wind erosion in sand dunes, also sand dunes afforestation as an effective and long lasting fixation mechanism. The study site was covered by petroleum mulch about 20 years ago and afforested by Prosopis juliflora. To study the effects of afforestat...
4 A newly emerging microbiological soil stabilization method, known as microbially 5 induced calcite precipitation (MICP), is tested for geotechnical engineering 6 applications. MICP is a promising technique that utilizes the metabolic pathways of 7 bacteria to form calcite precipitation throughout the soil matrix, leading to an increase 8 in soil strength and stiffness. This paper investigates...
Sedimentation is recognized as a major factor determining the ecosystem processes of lake beaches; however, the underlying mechanisms, especially in freshwater sand dunes, have been insufficiently studied. To this end, nine belt transects from nine freshwater sand dunes, classified into low (<23.7 m), medium (25.4-26.0 m), and high-elevation groups (>28.1 m) based on their elevations in 1972, w...
Manure-borne bacteria can be transported in runoff as free cells, cells attached to soil particles, and cells attached to manure particles. The objectives of this work were to compare the attachment of fecal coliforms (FC) to different soils and soil fractions and to assess the effect of bovine manure on FC attachment to soil and soil fractions. Three sand fractions of different sizes, the silt...
BACKGROUND AND AIMS Root soil penetration and path optimization are fundamental for root development in soil. We describe the influence of soil strength on root elongation rate and diameter, response to gravity, and root-structure tortuosity, estimated by average curvature of primary maize roots. METHODS Soils with different densities (1·5, 1·6, 1·7 g cm-3), particle sizes (sandy loam; coarse...
The effect of barriers of dry soil on the ability of Formosan subterranean termites, Coptotermes formosanus Shiraki (Isoptera: Rhinotermitidae), to construct tunnels and find food was evaluated. Termite movement and wood consumption in a three-chambered apparatus were compared between treatments with dry soil in the center container and treatments where the soil in the center container was mois...
Biological soil crusts (BSCs) are an important source of organic carbon, and affect a range of ecosystem functions in arid and semiarid environments. Yet the impact of grazing disturbance on crust properties and soil CO(2) efflux remain poorly studied, particularly in African ecosystems. The effects of burial under wind-blown sand, disaggregation and removal of BSCs on seasonal variations in so...
Application of bio-fertilizers and organic compounds is a way to reduce the use of chemical fertilizers. In order to study the effects of organic compounds and phosphate bio-fertilizer on some quantitative and qualitative attributes of ivy geranium (Pelargonium peltatum), a factorial experiment based on randomized complete blocks design (RCBD) was carried out using two factors including phospha...
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