Formation Of Soil Layer Research Articles

Changes in soil physical properties under the effect of irrigation

The mechanical composition of soils in the middle reaches of the Zarafshan River (Jambay, Samarkand, Payarik, Ishtikhon, Kattakurgan and Narpay districts) and the processes of formation of soil layers under the influence of irrigation water of general physical properties were scientifically analyzed. In this case, the inflow of the Zarafshan River played an important role in the formation of light agroirrigation strata. An increase in nutrients and humus with an increase in the amount of physical sludge over a long period of time (35–40 years) is positively assessed for thickening of the soil layer, but leads to an increase in bulk mass of 0.15–0.3 g / cm3 and soil compaction.

Issues of Soil and Ecological Efficiency of Land Reclamation and Justification of the Possibility of Restoration of the Properties of Chernozems

Currently, much attention is paid to scientific and reasonable development of ecologically favorable environment. In relation to soil cover is getting a good yield, the creation of a special parks, landscaping, design and creation of soil structures for lawns, sports fields. For science-based establishment of soil structures, it is necessary to know the water-physical properties of the material, the laws of movement of moisture, formation of soil layers. Methods for the study of soil is intimately associated with the doctrine of V. V. Dokuchaev on the soil. As a result of interaction of soil formation factors soil acquires certain properties, with the change of soil-forming factors, these properties will naturally vary. In parallel with the comprehensive study of the factors of soil formation in the study area are studied in detail the soil — their outward signs, and most importantly, the chemical and physical properties.

Mineralogical and Geochemical Trends in the Residual Soils above Basement Rocks in Ore Area, Southwestern Nigeria

Residual clays and laterite of economic values often occur within weathering profiles above basement rocks in tropical regions due to supergene enrichment and leaching of liable components. Previous studies in Ore area mainly on geochemistry of the basement rocks with scanty information on the weathered profiles. This study was carried out to determine the compositional characteristics of the basement rocks, the geochemical trends within the profiles above the parent rocks and the evaluation of their economic potentials.Petrographic study was carried out on thin sections of the rock samples. Elemental compositions of the rocks, clay, laterite, and top-soil were determined using Inductively Coupled Plasma-Mass Spectrometer (ICP-MS). Clay mineralogy was determined using X-ray Diffraction (XRD) analysis. Chemical index of Alterations (CIA) was calculated from geochemical data.Weathering of granite and banded gneiss in Ore resulted in the formation of soil layer, which ranged 0-0.5m, laterite 1.2-3m and clayey zone 2.9-3.0m. Quartz, plagioclase feldspars, microcline, biotite and hornblende were the essential minerals in the parent rocks. Granite and banded gneiss is high SiO2 (>65%) but low in MgO (<2.0%) and CaO (<4.0%). Kaolinite (60-80%), goethite (3-12%) and microcline (4-10%) were the dominant minerals in the XRD of the weathering profiles. Traces of illite were present only in granite. The CIA was generally > 85 indicating advanced state of weathering producing lateritic soil. The lateritic profiles over granite and banded gneiss of Ore area varied with the composition of the parent rocks. The clay layer has economic potential for ceramics, fertilizer and structural wares.

Mineralogy and Geochemistry of the Weathering Profiles above the Basement Rocks in Idi- Ayunre and Akure Districts, Southwestern Nigeria

Idi-ayunre and Akure areas are part of the basement complex of southwestern Nigeria and are predominantly consisted of gneisses, granite and migmatite with some minor quartz veins and pegmatite. These rocks have been greatly weathered to form clay, laterite and soils.Chemical analysis were carried out on basement rocks and exposed profiles. The weathering profile was subjected to X ray diffraction (XRD) analysis to determine mineralogical compositions whereas Chemical Index of Alteration (CIA) was calculated from the elemental concentrated data.Weathering of basement rocks in Idi-Ayunre and Akure districts resulted in the formation of soil layer which ranged 0-0.4m, laterite layer 1.2-2.2m, and clayey zone 3.8-6.6m. Quartz, plagioclase, microcline, and biotite were the main minerals in parent rocks. Some of the primary minerals such as biotite and K-feldspar have been weathered to form kaolinite. Quartz, kaolinite and goethite formed the dominant minerals revealed by X-ray diffraction on decomposed granite sequences. The results from chemical analysis showed that Al and Fe have been enriched in weathering profiles of banded gneiss, migmatite gneiss and porphyritic granite whilst on the other hand Ca, Mg, Mn, Na, K, Ti were reported to be depleted.. Silica was relatively stable from basement to the topsoil in the profile. The CIA generally ranged between 80 - 99The lateritic profiles over banded gneiss, granite and porphyritic granite of Idi-Ayunre and Akure areas varied with the composition of the parent rocks. The thick clayey layers could be of great economic importance for the production of ceramics wares and for constructional purposes.

A Great Revolution of the Earth-Surface Environment: Linking the Bio-Invasion Onto the Land and the Ordovician Radiation of Marine Organisms

The strontium isotopic composition of the oceans changed markedly at the Cambrian-Ordovician transition, some 500 million years ago. This isotopic shift was greatly affected by the first bio-invasion of the land and the ensuing terrestrial-surface environments in a chain reaction that included: 1) an attenuation of weathering on land, 2) changes in the outflow patterns of fluvial floods and the circulation patterns of groundwater, 3) marked regional differentiation of coastal environments, 4) the formation of soil layers, and 5) the eutrophication of estuaries by nutrient salts of terrestrial-biosphere origin. A series of these environmental changes culminated in the marine Ordovician biodiversification, an explosive flourishing of the Paleozoic evolutionary fauna that is characterized by a variety of filter and suspension feeders. The bio-invasion onto land was one of the greatest geobiological events in the Earth's history.