Noura Bakr

Influence of Ice on Soil Elemental Characterization via Portable X-Ray Fluorescence Spectrometry

Field portable X-ray fluorescence (PXRF) spectrometry has become an increasingly popular technique for in-situ elemental characterization of soils. The technique is fast, portable, and accurate, requiring minimal sample preparation and no consumables. However, soil moisture > 20% has been known to cause fluorescence denudation and error in elemental reporting and few studies have evaluated the presence of soil moisture in solid form as ice. Gelisols (USDA Soil Taxonomy), permafrost-affected soils, cover a large amount of the land surface in the northern and southern hemispheres. Thus, the applicability of PXRF in those areas requires further investigation. PXRF was used to scan the elemental composition (Ba, Ca, Cr, Fe, K, Mn, Pb, Rb, Sr, Ti, Zn, and Zr) of 13 pedons in central and northern Alaska, USA. Four types of scans were completed: 1) in-situ frozen soil, 2) re-frozen soil in the laboratory, 3) melted soil/water mixture in the laboratory, and 4) moisture-corrected soil. All were then compared to oven dry soil scans. Results showed that the majority of PXRF readings from in-situ, re-frozen, and melted samples were significantly underestimated, compared to the readings on oven dry samples, owing to the interference expected by moisture. However, when the moisture contents were divided into > 40% and < 40% groups, the PXRF readings under different scanning conditions performed better in the group with < 40% moisture contents. Most elements of the scans on the melted samples with < 40% moisture contents acceptably compared to those of the dry samples, with R 2 values ranging from 0.446 (Mn) to 0.930 (Sr). However, underestimation of the melted samples was still quite apparent. Moisture-corrected sample PXRF readings provided the best correlation to those of the dry, ground samples as indicated by higher R2 values, lower root mean square errors (RMSEs), and slopes closer to 1 in linear regression equations. However, the in-situ (frozen) sample scans did not differ appreciably from the melted sample scans in their correlations to dry sample scans in terms of R 2 values (0.81 vs. 0.88), RMSEs (1.06 vs. 0.85), and slopes (0.88 vs. 0.92). Notably, all of those relationships improved for

Characterization of placic horizons in ironstone soils of Louisiana, USA.

Placic horizons, defined as thin, wavy, hardened layers of iron and organic matter, are rare within the United States, occurring only in Washington, Alaska, and Hawaii. While ironstone is common in many soils of the southeastern United States, it is not known to contain appreciable organic matter. As a pilot study evaluating the justification for a larger study on ironstone in Louisiana, a 40 m lateral exposure with suspected placic horizons was evaluated in Vernon Parish, Louisiana. Results of laboratory analysis show elevated levels of iron and organic matter in the suspect horizons that meet the criteria of placic horizons as defined by the Soil Survey Staff. Based on the results of this study, additional evaluation of multiple pedons with similar features is warranted. Should additional pedons demonstrate similar properties, a new great group of ‘Petrudepts’ would be needed to describe both the placic horizons in the pedon and the udic moisture regime in which they occur.

Soil series and land use impacts on major soil properties: a quantitative comparison

Human-induced soil change is attracting increasing attention, yet how to quantitatively measure anthropogenic impact on changes in soil properties remains unclear. Eight selected soil properties—bulk density (BD), sand, silt, and clay content, pH, soil organic matter (SOM), total carbon (TC), and total nitrogen (TN)—at four soil depths (0–10, 10–20, 20–30, and 30–40 cm) were measured across three soil series (Gallion, Latanier and Sharkey) in south-central Louisiana, USA, to quantify changes in soil properties as a function of three contrasting land use types, i.e. forest, cropland, and Wetlands Reserve Program. Partial eta-squared values (η2) derived from two-way analysis of variance were used to quantitatively compare natural factors (soil series) and anthropogenic impact (land use) on these soil properties. Results showed that properties such as BD, pH, SOM, TC, and TN could be easily changed by anthropogenic disturbance, especially at 0–10 cm, while soil texture was mainly a natural factor. The anthropogenic factor accounted for 55.2%, 39.5%, 33.2%, and 36.0% of changes in the soil properties at 0–10, 10–20, 20–30, and 30–40 cm depth, respectively. These findings highlight the anthropogenic impact on selected soil properties.

Land Use/Land Cover and Vegetation Status

With an area around one million square kilometers, five land use/land cover (LULC) classes are distinguished in Egypt, namely, agricultural land, barren land, urban areas, natural vegetation (aquatic and terrestrial), and water bodies. In this chapter, each LULC class is discussed, and their changes are briefly introduced. The LULC in Egypt is not enormously varied as over 90% of Egypt soils are desert, and other economic activities and settlement existed in around 4 to 5%. Although the agricultural land represents around 4% of the total area, the agricultural sector is a crucial player in the Egyptian economy. The old cultivated land (Oldlands) are observed in the Nile Valley and Delta, whereas, the Newlands represent the horizontal expansion in the desert, mainly around the fringes of the Nile Delta. Wheat, rice, barley, and maize are the main cultivated cereal crops that are recognized in Egypt. Both cereal crops yield and their cultivation extend are almost doubled within the last five decades. Barren lands are observed in three locations, western desert, eastern desert, and the Sinai Peninsula. Egypt oases and depressions locate in the western desert, the Red Sea Mountains are in the eastern desert, and the highest spot in Egypt (St. Catherine Mountain) locates in the Sinai Peninsula. The urban sprawl is one of the main anthropogenic challenges that causes an observed change in LULC in Egypt. Thus, the government adopts several policies to relocate Egyptian outside the Nile Valley and Delta regions by constructing new communities in the desert and conserved the Oldlands from being lost due to the urban sprawl. Besides Nile River and its branches, other water bodies such as the five northern lakes, Nasser Lake, and Toshka depression are recognized. The northern lakes are subjected to change as a result of both environmental and anthropogenic impacts.

Egyptian Natural Resources

Abstract: The Arab Republic of Egypt is the main northeastern entrance of Africa continent. The total area of Egypt territory is around one million square kilometer and occupied by approximately 95 million inhabitants who live on about 4% of this area. This chapter presents an overview of the land, water, and human resources in Egypt. Egypt land is geographically divided into five sections: Western Desert, Eastern Desert, Sinai Peninsula, Nile Valley, and Nile Delta. These sections involve 33 soil units in which sandy areas and loamy sand/sandy loam soils cover over 57% of their surface. Despite that, agriculture is the fundamental economic activity in Egypt. The Egyptian agricultural lands could be classified as Oldlands and Newlands. The Oldlands are assigned for the fertile and intensively cultivated lands in Nile Valley and Delta that have been farmed since ancient time till now, whereas the newly reclaimed areas that have been cultivated relatively recently or in the process of reclamation now are known as Newlands. The natural water resources in Egypt are inadequate since the primary water source is the annually fixed share of Nile River of 55.5 BCM that is utilized for almost all human activities despite the high growth rate of population. The Egyptian government adopts strategies to utilize the non-conventional water resources (mainly recycled agricultural drainage, shallow groundwater, and treated wastewater) in irrigation as the agricultural sector consumes 80–85% of available freshwater in Egypt. At the administrative level, Egypt involves 27 governorates in which New Valley governorate represented 42% of total Egypt’s area and occupied with only 0.25% of the Egypt total population. Conversely, the Great Cairo (involves Cairo, Giza, and Kalyoubia governorates) occupied by around 25% of the total population. Agricultural sector supports the livelihood to approximately two-thirds of the Egyptians and considers the primary source of income to about 60% of Egyptians.