A field study investigating the potential use of phosphorus combined with organic amendments on cadmium accumulation by wheat and subsequent rice

A field study was performed to determine the efficiency of diammonium phosphate (DAP) applied alone or combined with biochar, lignite, and farmyard manure (FYM) on growth and cadmium (Cd) accumulation in wheat and rice. Before crop sowing, different treatments were applied in the field such as a control (T₁), DAP alone (0.1%, T₂), DAP + lignite (0.05% each, T₃), DAP + FYM (0.05% each, T₄), and DAP + biochar (0.05% each, T₅). Afterwards, the wheat seeds were sown in the soil. At wheat postharvest, rice was sown without any further treatment. Raw effluent was applied as an irrigation source during the whole growth period of both crops since it is the common practice of the farmers of study area. It was revealed that the use of amendments enhanced the yield and photosynthesis but lowered the Cd contents in straw as well as grains of both crops. In both crops, the highest yield of straw and grain was found in DAP + FYM whereas the lowest Cd concentration was found in DAP alone. The ammonium bicarbonate-DTPA extractable Cd of post wheat and post rice soils were decreased while the soil pH and immobilization index were increased in all treatments as compared with the control. The present field study highlighted that the DAP + FYM can be effective in increasing yield with decreased Cd concentrations in crop grains.     

Gradient-based Pareto optimal history matching for noisy data of multiple types

The advantages of the simultaneous integration of production and time-lapse seismic data for history matching have been demonstrated in a number of previous studies. Production data provide accurate observations at particular spatial locations (wells), while seismic data enable global, though filtered/noisy, estimates of state variables. In this work, we present an efficient computational tool for bi-objective history matching, in which data misfits for both production and seismic measurements are minimized using an adjoint-gradient approach. This enables us to obtain a set of Pareto optimal solutions defining the optimal trade-off between production and seismic data misfits (which are, to some extent, conflicting). The impact of noise structure and noise level on Pareto optimal solutions is investigated in detail. We discuss the existence of the “best” trade-off solution, or least-conflicting posterior model, which corresponds to the history-matched model that is expected to provide the least-conflicting forecast of future reservoir performance. The overall framework is successfully applied in 2D and 3D compositional simulation problems to provide a single least-conflicting posterior model and, for the 2D case, multiple samples from the posterior distribution using the randomized maximum likelihood method.     

Spectral wave characteristics along the central coast of eastern Red Sea

The Jeddah coast lies in the central eastern Red Sea, which is characterized by the predominant northwest winds and the associated wind waves throughout the year. A detailed investigation on the spectral wave characteristics in the nearshore regions of the Jeddah coast has not been carried out yet, primarily due to the lack of data. In the present study, we have analyzed the available wave spectra measured at two nearshore locations along the Jeddah coast using wave gauges. The wave spectra were separated into wind sea and swell components using a frequency-based algorithm, and the integral wave parameters corresponding to each component were derived. Although the measurements were limited to the summer season, notable features such as the diurnal variability and the superimposition of wind seas and swells have been identified from the spectra. The superimposition is mainly due to the interaction of the young swells propagated from the northern Red Sea and the local breezes prevailing along the coast at certain periods in a diurnal cycle. Based on the wave speed calculations and the estimated time shifts between the wind and waves, the potential swell regions have been backtracked.     

Geological structure of the coastal aquifer in the southern part of the Gaza Strip,Palestine

The current study introduces the geological subsurface cross-sections in the southern part of the Gaza Strip to show the structure of the aquifer in the area. The cross-sections give evidence of four subaquifers of the coastal aquifer in the southern part of the Gaza Strip. These cross-sections give the natural reasons for the deterioration of the groundwater in the study area. The results show presence of clay lenses that prevent the replenishment processes of the aquifer of fresh water from the rainfall and returns flow from agricultural activities. Lithological formation was evident as one of the natural causes which accelerate destroying process of the coastal aquifer. The results also show that the structure of the aquifer causes the increase of the groundwater salinity in the Gaza Strip. The cross-sections had shown the shortage of storage capacity of high quantities of fresh water in the coastal aquifer in these areas. The role of lithological formation was evident as one of the natural causes to accelerate the process of destroying the coastal aquifer.     

Exploring the association between the occurrence of earthquakes and the geologic-tectonic variables in the Red Sea using logistic regression and GIS

Al-Ahmadi et al. (Arab J Geosci doi:10.1007/s12517-013-0974-6, 2013) applied spatial pattern analysis techniques to a seismic data catalogue of earthquakes beneath the Red Sea in order to explore and detect global and local spatial patterns in the occurrence of earthquakes over the years from 1900 to 2009 using a geographical information system (GIS). They found that the techniques of spatial pattern analysis that they applied could detect global and local clusters and broader spatial patterns in the occurrence of earthquakes and concluded that earthquakes with higher magnitudes were notably concentrated beneath the central and southern areas of the Red Sea, while earthquakes with low and moderate magnitudes were concentrated beneath the northern area of the Red Sea. The aim of this paper is to report on the application of logistic regression models to explore the associations between the likelihood of the occurrence of an earthquake beneath the Red Sea and four selected variables, namely: (1) proximity to the boundary of the African–Arabian plates, (2) proximity to transform faults, (3) proximity to the mid-Red Sea ridge and (4) the stage of rift evolution. The study was undertaken to evaluate the potential of logistic regression modelling for research exploring potential associations between earthquakes and geological and tectonic variables. The results revealed that none of the assumptions underpinning the logistic regression models had been violated for the three logistic regression models that were used in this research. The authors inferred that the occurrence of the earthquakes beneath the Red Sea was statistically significantly associated with the proximity to the African–Arabian plate boundary. We concluded that earthquakes of moderate magnitudes occurred in the zone which represents the late evolutionary stage of the Red Sea rift, including the transition zone beneath the central area and the late-stage continental rift zone beneath the northern area of the Red Sea. In contrast, earthquakes with high magnitudes tended to occur in close proximity to the mid-ridges of the Red Sea.     

Impact of the geomorphology and soil management on the development of waterlogging in closed drainage basins of Egypt and Saudi Arabia

This paper investigates the interplay of the catchment geomorphology, hydrology and soil properties on the development of waterlogging and land degradation within different dry land catchments in Egypt and Saudi Arabia. Multi-temporal remote sensing data of the Landsat Thematic Mapper and Enhanced Thematic Mapper were collected and processed to detect the land cover changes and development of cultivations within the two areas. The Shuttle Radar Topography Mission Digital Elevation Model were hydrologically processed to delineate the catchment morphometrical parameters and to examine the spatial distribution of cultivated fields and their relation to the extracted drainage networks. The fluvial channels of the Farafra Oasis have largely been obliterated by the prevailing aridity and often buried under aeolian deposits. The soil of these areas are mainly lithic with a high calcium carbonate content, thus limiting the downward percolation of excess irrigation water and therefore develop perched water table and seepage through the buried fluvial channels. On the other hand, the cultivations of Tabuk catchment (which has similar geomorphologic setting to the Farafra Oasis) have shown no signs for waterlogging. This situation is could be related to the different soil properties; the spatial distribution of cultivated areas and the adopted irrigation methods via pivots. The inactive alluvial channels, landforms and irrigation methods have to be considered when planning for a new cultivation in dry land catchments to better control waterlogging hazard. The ‘dry-drainage’ concept can be implemented as the drainage and seepage water, which can be conveyed into certain abandoned playas for evaporation.     

Air quality and elemental enrichment factors of aerosol particulate matter in Riyadh City, Saudi Arabia

Air particulate matter (PM) samples were collected from June 2006 to May 2007 for determination of chemical elements. PM samples were taken in two size fractions (PM_2.5 and PM₁₀) with MiniVolume air samplers on rooftops of various buildings (15–25 m above ground) in the city of Riyadh. The samples were subjected to X-ray fluorescence analysis to measure major (Na, Mg, Al, K, Ca, Si, P, S, and Fe) and trace elements (Mn, Ni, Cu, Zn, and Ba). The results showed that the PM concentrations were higher for PM₁₀ compared to PM_2.5, indicating that the major PM source was local dust. Also the spatial distribution with high PM concentrations was observed in the south and southeast of the city and the lowest levels were in the center and northeast of the city. This spatial distribution was attributed to different factors such as wind direction and velocity, emission from cement factories, and the presence of buildings, trees, and paved streets that reduce the amount of dust resuspended into the atmosphere. The air quality of the city was found to range from good to hazardous based on PM_2.5, and from good to very hazardous based on PM₁₀. The element-enrichment factors revealed two element groups according to their changing spatial behavior. The first group showed no significant spatial changes indicating they have the same common source. The second group (mainly S and Ni) exhibited significant changes as expected from anthropogenic inputs. The origin of S is possibly a combination of minerals (CaSO₄) and fossil fuel combustion. The source of Ni is probably from fossil fuel combustion.     

Integrated diagenesis and sequence stratigraphic study of tidal sandstones: the Adedia Formation (Cambro-Ordovician), Sinai, Egypt

This work examines the different effects meteoric versus marine diagenesis had on Cambro-Ordovician tidal sandstones during episodes of fluctuating sea level. The distribution of diagenetic fabrics was compared to a sequence stratigraphic framework. Initially, a rise in relative sea level (RSL) resulted in deposition of transgressive systems tract sands directly onto crystalline basement. These sandstones display evidence of limited cementation by marine, grain-fringing dogtooth-like and fibrous calcite. A fall in RSL resulted in the progradation of a tidal flat complex and deposition of highstand systems tract (HST) and lowstand systems tract (braided fluvial) sandstones. Contemporaneous meteoric-water flux into sands of all the systems tracts occurred. Sequence boundaries (SB) are marked by fluvial incision of tidal sands and by the development of palaeosols. Meteoric incursion during sea-level lowstands resulted in the dissolution and kaolinitization of feldspars, micas and mud intraclasts in all systems tracts, but is most extensive in HST sandstones below the SB. The effect of meteoric-water flux on the dissolution of marine calcite cements is poorly known. Mesogenetic alterations include intergranular pressure dissolution and formation of variable amounts of syntaxial quartz overgrowths in all systems tracts. Telogenetic alteration (i.e. weathering) in the sandstones includes the formation of goethite and calcite. Thus, the integration of diagenesis with sequence stratigraphy provides a useful tool with which to understand reservoir-quality distribution in sand-dominated, tidal sediments.     

GIS-based estimation of flood hazard impacts on road network in Makkah city, Saudi Arabia

Makkah city, Saudi Arabia, is periodically exposed to flash floods that result in major human and economical damages. That is due to several factors including its rugged topography and geological structures. Hence, precise assessment of floods becomes a more vital demand in development planning. A GIS-based methodology has been developed for quantifying and spatially mapping the flood characteristics. The core of this new approach is integrating several topographic, metrological, geological, and land use data sets in a geographic information system (GIS) environment that utilizes the curve number method of flood modelling for ungauged arid catchments. Based on the estimated flood volume of sub-basins, a hazard factor has been developed to quantify the expected hazard level for each road. Applying this proposed approach reveals that 21?% of the road network in Makkah city is subjected to low flood hazards, 29?% is facing medium hazards, and 50?% of roads are exposed to harsh flood impacts. The developed approach may be considered a digital precise method that can be easily re-run, in other situations or regions, to estimate flood hazards on roads.