In the past, several approaches (physical, chemical, and micro morphological) have been used to study sodic soils but the emphasis was to study the soil pore, crust, structure, root penetration, microbial activity and water infiltration in different soils (Naidu et al., 1995). However, the columnar structure formation and salt movement within the structure under sodic soils has never been discussed. Sodic soils are the soils with high exchangeable sodium percentage of greater than 15% (U.S. Salinity Laboratory Staff, 1954) and/or the soil with high sodium as compared to calcium and magnesium (Salcon, 1997). Excess exchangeable sodium (ESP) affects the physical and nutritional properties of the soil with reduction in crop growth. Several studies had reported in studying the change in soil chemistry under sodic soils (Aylmore and Quirk 1959; Quirk and Schofield 1955; McNeal and Coleman 1966; Gardner et al., 1959). To identify the sodic soils, several physical (soil texture, structure, and color) and chemical methods (pH, electrical conductivity, exchangeable sodium percentage, calcium carbonate, hydrolytic conductivity, and sodium absorption ratio) have been used but micromorphological methods are rarely practiced due to expensive methodology and labor intensive.
Physical methods generally practiced in the field to identify the soils physical parameter. For example, soil horizon, color, texture, structure, concretion, and salt accumulation. The vertical section from the surface were dig up to the parent material and designate them into different horizon on the basis of soils color, texture, structure etc. Sodic soils develop a dense prismatic or columnar structure below the surface horizon, which restrict the water/nutrient movemen...
... middle of paper ...
...raphical position of sodic soils were studied by micromorphological techniques (Pal et al., 2003) and indicated the soil stress in the thin section which is due to the Holocene tectonics and shows the variation of sodicity in different topographical position. Micromorphology is frequently been used to describe soil structure, normally by evaluating the sizes and shapes of soil pores (Norton and Schroeder, 1987).
Understanding the cause/process of formation of sodic soil will help in its management and reclamation. The thin section technique of micromorphology will help in better understanding for the identifications, distributions, and quantifications of sodic soils along with physical and chemical methods. There is a need to present a micro morphological data in clear, logical, and standardized manner for sodic soil and the salt/clay movement in column structure.
The central belt of the Franciscan Complex represents older and more metamorphosed units of rock best characterized as a melange. Blocks of graywacke, greenstone, chert, limestone, and blueschists are sheared and thrust upon one another in a choatic mix (Isozaki and Blake, 1994). In contrast to the coastal belt, metamorphism is higher in grade here and dominated by pumpellyite which formed within the matrix of graywacke (Hagstrum and Murchey, 1993). The mixing of these units makes a stratigraphic subdivision difficult but analysis of the graywacke slabs indicates that the depositional environment was also deep sea, near to the continent. Turbidity currents in this environment deposited much of the sediment in both the coastal and central belts.
The primary methods when comparing forensic soil samples employ the use of microscopes and manually examining the colour, texture, density gradient and mineralogical content. After a primary manual examination has been conducted x-ray diffraction along with another method such as x-ray fluorescence are used to discover the chemical composition of the sample. These methods are considered to be useful for discriminating between samples which have inorganic minerals, however Bommarito et al (2006) believe a different method is needed to discriminate between organic compounds, high performance liquid chromatography (HPLC) satisfies these requirements Ion chromatography is also investigated in their study as it has not been applied to forensic soil comparisons before. ...
Mississippi has a variety of different soils .The three general soils are 1) the river flood plain, known as the Delta, 2) a loess region, or bands of soils formed in windblown material that adjoins the Delta, and 3) Coastal Plain. The Mississippi Delta is better for growing row crop, while the loess and Coastal Plain region are better for animal production and forestry. The loess and Coastal Plain regions are divided based on similar soils, geology, climate, water resources, and land use called Major Land Resource Areas. The Mississippi Delta’s soil comes from sediments left by flooding various rivers in the region, rather than being a typical Delta formed by the mouth of a river. In the Delta most of the land is farmed, with three-fourths of the cropland to the north. Controlling surface water and drainage are major soil management issues. In the Delta soils are naturally diverse because of their alluvial origin. Particle sizes within the sediment decrease as distance from the originating stream increase. Another factor in Delta soil formation us surface water movement over time, because soils that formed under standing water have different properties than soils formed under moving water. Soils with large amounts of clay particles have unique features. When the soil is dry, small round aggregates form at the surface that look like shotgun buckshot, which is where the popular name for Delta clay soils “buckshot” came from. Soils with large clay content have very slow water filtration rates; this has led to significant aquaculture and rice production in the region. When floodwaters receded in the Delta, strong winds blew some of the dry sediment left by flooded river to the adjacent uplands to form the loess areas. Because of eas...
Palaeogeography deals with the reconstruction of physical geographical conditions for the eras of the Earth's history. The term comes from the Greek παλαιός (palaiós) meaning ‘old’ and γεωγραφία (geōgraphía) meaning ‘a description of the earth’ and seems to have been introduced in the Earth sciences vocabulary as ‘Palaeo-Geographie’ by Ami Boué (1794‒1881), a French‒Austrian geologist, in his publication Einiges zur palaeo-geologischen Geographie (Boué, 1875, p. 2). Palaeogeography focuses on the distribution of land and sea, the spread of mountains and volcanoes and the expansion of glaciations, among others. The results are presented in geographic depictions called palaeogeographic maps. A special kind of palaeogeograpahical map is palaeobiogeographical maps depicting the distribution of
As we have observed throughout the centuries, colonialism has immensely shaped the majority of countries of modern society. In the essay “The Impact of Colonization and Western Assimilation on Health and Wellbeing of Canadian Aboriginal People”, Cathy MacDonald & Audrey Steenbeek developed significant points that reflect as connections to the essay “Virgin Soils Revisited” emphasizing the devastating impact colonialism has had on the wellbeing and health initiatives imposed on the Native Americans and the Aboriginal people of Canada to this day. Both indigenous populations have endured the hardships of poor health, racial issues such as oppression, and cultural assimilations due to the long-lasting effects of colonialism.
To ensure validity, measure abiotic factors including soil temperature, light intensity, soil texture, and soil pH
Describe the types of farming that occur in the savannah biome in the Sahel region.
Africa has a regular coastline characterized by few indentations. Because of the smooth coastline, natural harbors were non-existent. Today, however, there are important coastal cities, such as Lagos and Dakar. With the exception of the Mediterranean coast, most of the coastline is low-lying , generally narrow and rising sharply to high elevations. The African climate and topography varies greatly. Although temperatures are usually high, due to being so close to the equator, rainfall, soil quality and elevations are of various degrees. Because most of the African continent has not been covered by water for millions of years, soils have developed according to their weathering e...
Zakharov, S. A. 1927. Achievements of Russian science in morphology of soils. Russian Pedological Investigations, Soviet Acad. Sci. (Leningrad), Chap. 2 (47 pp.).
Davis, J. G., R. M. Waskom, and T. A. Bauder. Managing Sodic Soils. Colorado State
Salt and the effects it has on plants in the germination of seeds has been studied for years. There are various factors involved in seed germination like water intake and salinity. Osmosis, "movement of a solvent (such as water) through a semipermeable membrane (as of a living cell) into a solution of higher solute concentration," has always been a significant process in the intake of water for plants. Without the process of osmosis, plants would have been extinct by now. Salt can be either beneficial or detrimental to seed
The most commonly encountered species of sorghum in Africa is Sorghum bicolor (Harland & de Wet, 1972; Norman, Pearson, Searle, 1995). It is a cereal grain plant of the family Gramineae. Historically, Sorghum bicolor is a grass species mainly cultivated for food to feed humans and animals and for producing ethanol (CAC, 2011). It originated in northern Africa, but now cultivated widely in tropical and subtropical regions. The crop although treated as an annual, is a perennial that is mostly found in the tropics and harvested many times (Stroade, Boland & Taylor, 2013). Most cultivated varieties of sorghum have their origin in Africa, where they grow on savannah lands and cultivated extensively
Soil salinity is said to be “bad” for plant growth but is this really true? Is it just a big misunderstanding? Is it really the salts 'fault'? Are there no solutions to fixing this problem? These are some of the questions many people should be asking before deciding if salt is a friend or foe. Instead of just following whatever others say, people should know exactly how soil salinity is affecting crops and why this is happening. To know our enemy, in this case 'the salt', experiments has to be done, results must be gathered and processed and there must be an explanation to understand the different outcomes and results. We decided to find out everything about soil salinity and how it affects plant growth because plants are a huge part of our life, we live and breathe because of them and we want them to flourish. First, these are some information and questions that will make it easier to understand the whole concept altogether.
When studying plant nutrition, it is important to analyze the sources of the nutrition. Plants absorb their nutrients using their roots in the soil, however soil is not a uniform nutritive source. The plant’s wellbeing depends greatly on the quality, composition, and thickness of the soil. To help categorize such a broad topic, scientists have implemented a naming scheme for the different levels of soil. The first layer is closest to ...