Search results for " SOIL"
showing 10 items of 774 documents
Spatial microbial community structure and biodiversity analysis in "extreme" hypersaline soils of a semiarid Mediterranean area
2015
In recent years specific attention has been paid on the biotechnological potential of microorganisms in extreme soils, in particular in saline soils. Salinity is one of the most widespread soil degradation processes on the Earth, and saline soils can be defined as extreme soils or border line habitats in which several factors, as high salt content, may limit the growth of organisms. In this study, the physical, chemical and microbiological soil properties were investigated in the shallower horizon of natural saltaffected soils in Sicily (Italy). The main aim of the research was to evaluate the structure and diversity of bacterial and archaeal communities by terminal-restriction fragment len…
Assessment of soil suitability for improvement of soil factors and agricultural management
2019
The dramatic growth of the world&rsquo
The effect of alternating different water qualities on accumulation and leaching of solutes in a Mediterranean cracking soil
2002
The relevance of bypass flow on water flow, solute or pesticide transport is becoming increasingly recognized. Recent investigations proved that soil salinization may be influenced by bypass flow, i.e. the rapid transport of water and solutes via macropores and/or shrinkage cracks to subsoil and groundwater. This paper explores the role of bypass flow in the process of accumulation and leaching of solutes, as well as of sodium, in a Mediterranean cracking soil irrigated with saline/sodic waters. The results of bypass flow experiments performed on undisturbed soil cores showed that leaching of solutes occurred in concomitance with bypass fluxes when a low salinity solution was alternated wit…
Laboratory testing of Beerkan infiltration experiments for assessing the role of soil sealing on water infiltration
2018
Abstract Soil surface sealing is a major cause of decreased infiltration rates and increased surface runoff and erosion during a rainstorm. The objective of this paper is to quantify the effect of surface sealing on infiltration for 3 layered soils with different textures for the upper layer and investigate the capability of BEST procedure to catch the formation of the seal and related consequences on water infiltration. Rainfall experiments were carried out to induce the formation of the seal. Meanwhile, Beerkan infiltration runs were carried out pouring water at different distances from the soil surface (BEST-H versus BEST-L runs, with a High and Low water pouring heights, respectively) f…
Design Procedures for Soil-Lime Stabilization for Road and Railway Embankments. Part 1-Review of Design Methods
2012
AbstractWhen selecting the appropriate materials for constructing road infrastructures, an important way for minimizing both the economical and environmental impact is to make use of lime for treating soils that are not suitable for road or railways construction.Advances in lime stabilization technique allowed the successful use of this technique also for improving the bearing capacity of the subgrade, with noticeable savings on both aggregate and disposal charges.In this paper a review of internationally adopted design methods for soil-lime mixture is presented, in order to compare testing methods and requirements of the adopted criteria, as discussed in Part 2.
Assessing Field and Laboratory Calibration Protocols for the Diviner 2000 Probe in a Range of Soils with Different Textures
2016
Frequency domain reflectometry (FDR) downhole sensors have been increasingly used for soil moisture field monitoring because they allow measurement, even continuously, along a soil profile. Moreover, they can also be installed with minimal soil disturbance around the access tube. The objectives of the paper were to assess the field and laboratory calibration protocols for a FDR capacitance probe (Diviner 2000) for a range of soils characterized by different particle size distributions and shrink/swell potential and to propose a practical and effective protocol on the basis of undisturbed soil samples, accounting for soil shrinkage/swelling processes characterizing swelling clay soils. The e…
Spatial Distribution of Soil Hydrological Properties in the Kilombero Floodplain, Tanzania
2017
Analysis and interpretation of soil properties dynamics is a keystone in understanding the hydrologic responses and yield potential of floodplain wetlands. This study characterizes the distribution and spatial trends of selected soil physical properties in the Kilombero floodplain, Tanzania. A total of 76 composite soil samples were taken from 0 to 20 cm and 20 to 40 cm depth in a regular grid design across three hydrological zones, related to flooding intensity defined as fringe, middle, and riparian during the rainy season of 2015. The samples were analyzed for soil texture, bulk density, organic carbon, and saturated hydraulic conductivity. Seasonal soil moisture content was monitored at…
Impact of acidic volcanic emissions on ash leaching and on the bioavailability and mobility of trace metals in soils of Mt Etna
2021
We report on original geochemical data, which combine the rainfall trace metal contents from three different areas of Mt. Etna, variably fumigated by the volcanic plume, and those from soils, collected over the whole volcano. Trace element contents in rainfall appear mostly related to acidic ash leaching, while only for the most volatile elements (Cu, Zn, Cd, Pb, As, Sb, Tl, Se) we suggest a derivation from magmatic degassing. We analyzed separately the labile fraction of soil samples, considered the fraction bioavailable to plants and soil organisms living in. The complexing medium used to extract the bioavailable fraction simulates the growth environment of plant roots.The contents of tra…
Accelerated mineralisation of atrazine in maize rhizosphere soil
2002
International audience; The mineralisation rate of atrazine measured in soil pre-treated with this herbicide, was significantly higher in the maize rhizosphere than in bulk soil. Maize rhizosphere was also shown to significantly increase microbial biomass C as compared with bulk soil. Ribosomal intergenic spacer analysis conducted on nucleic acids extracted directly from soil samples revealed that the structure of microbial communities observed in the rhizosphere was slightly different from that of bulk soil. The quantification of the relative amount of the gene atzC, which encodes an enzyme involved in atrazine mineralisation, was carried out on soil nucleic acids by using quantitative-com…
Factors Influencing Point Measurement of Near-surface Saturated Soil Hydraulic Conductivity in a Small Sicilian Basin
2017
Hydraulic conductivity of saturated soil, Ks, controls many hydrological processes. Parameterization of basin hydrological models in terms of Ks is complicated and uncertain owing to the very high spatial variability of this soil property. A small Sicilian basin was intensively sampled by the simplified falling head technique to obtain spatially distributed Ks data, and an attempt to explain their spatial variability on the basis of soil physical characteristics, digital elevation model-derived topographic attributes and land cover was carried out. High Ks values were obtained when clay content was low and both elevation and mean slope were high. Moreover, differences in Ks among land cover…