Numerous Disciplines Provide Different Definitions of Soil - Assignment Example

Soils Numerous disciplines provide different definitions of soil. However, many people have confused its meaning and used mud and dirt to refer to it. Traditionally, soil has been defined as the material on the surface of the earth that nourishes and supports plant life. This definition includes the rocks, snow, water and air, all which can support plant life (Indiana University 1). For sure, soil cannot be classified as a rock; this is because soil is composed of particles, which are loosely held together. With this in mind, we can regard soil as a conglomeration of sediments with exceptional and distinctive attributes. In this regard, soil refers to an inert and loose weathering product of the primary rock found on the surface of the earth (Bryant-Mole & Watts 25). Weathering refers to the physical and biogeochemical processes that result to disintegration and decomposition of earth materials such as rocks and sentiments (Indiana University 2). Soils comprise of air, liquids, organic matter and minerals. Soils in Indiana have different attributes, which give them distinctiveness. They differ in texture, color, chemical and biological attributes and structure. These attributes determine the amount of water and air in and to be held in the soils (Burton 2) Soil texture is determined by the comparative fractions of sand, silt and clay (Brady & Weil 53). Soil texture refers to the sizes of the particles that constitute the soil. Sand, silt and clay are used in determining the sizes of soil particles (Bryant-Mole & Watts 37). The presence of sand particles in soils makes the soil be characterized by large soil particles which are gritty. On the other hand, the presence of silt particles in a soil makes the soil particles moderate in size and smooth while presence of clay characterizes a soil as of smaller particles and sticky. The way the soil particles are assembled determines the structure of the soils. Therefore, soil structure refers to the arrangement and aggregation of soil particles (Miller & Turk 72). Soil structure controls aeration and the amount of water in the soil. Soil particles are either conglomerated as a group of particles or as single grains of particles (Bryant-Mole & Watts 43). In sandy soils, the particles are single grained while in clay soils, the soil particles are aggregated. The single grain particles are solid while the aggregates are porous in character. Soils aggregate differently forming different soil structures. In describing the structure of soils in Indiana, soil scientists note the size, shape and development of aggregates. In Indiana, majority of the sub soil is typified by a sub-angular blocky structure and 0.5 to 2 mm in size (Indiana University 3). In addition, platy soil structures are present in Miami soils. Prismatic structure is also present in Miami. The cracks between the aggregates dictate the flow of water and plant roots in the soil (Burton 2). In the prismatic soil structures, the cracks are primarily vertical; this is the same direction that water and roots follow. Needless to say, the size of the aggregates among the Indiana soils establishes the distance between the natural cracks (Indiana University 3). For instance, soils with a prismatic structure such as Brookston have prism shaped aggregates and about 0.5 to 1 inch will have many cracks due to the small sized aggregates while soils with prism shaped aggregates and of about 4 inches across will have few cracks through which water and roots can penetrate. Soil color refers to how the soil appears in natural light. Classifications of soils in terms of color are aided by a standardized book of color. This book identifies the quantity of yellow, blue and green colors in the soil (Miller & Turk 82). Soil structure, color and texture form the basis through which geologists classify soils (Bryant-Mole & Watts 55). Soils in Indiana are classified according to the amount of silt, sand and clay particles present in the soil (Burton 2). Soils with a high number of sand particles are referred to as sandy soils; those with silt soils referred to as silty soils while those with a high number of clay particles are referred as muck soils. On the other hand, a mixture of the three different types of particles results to a soil referred to as loam soil. Soils form as a result of weathering processes. This process is influenced by the climatic condition of the region, the topography, parent material, time taken and biological processes. These factors are intertwined (Indiana University 4). For instance, topography determines the vegetation in the region, while the climatic condition dictates the type of vegetation on the surface. A change in any of these factors contributes to a different kind of soil. In this regard, the different factors have contributed to the different soil types in Indiana. Soil changes and develops with time. A soil that has continued to develop over time is finer due to the continued processes of weathering. The process of soil formation starts with accumulation of organic material on the surface, then dissolution of carbonate minerals, leaching of bases such as magnesium and calcium, movement of clay to lower layers of soils, and cementing or soil particles to each other which forms soil structure (Brady & Weil 76). In addition, these processes results to the formation of soil horizons. Soil horizons are layers with distinct properties. The properties, type and thickness of the horizons are determined by the soil forming processes (Burton 2). Soil horizon and layers make up the soil profile. A close observation of the soil profile of a hill at West Lafayette in Indiana shows that soil profile changes over short distances. The soil consists of five horizons, O, A, B, E, C. The table below indicates the soil profile of the region and its distinctive features. Horizon Color Features O Dark brown to black Made up of decomposing organic matter A Dark Brown to gray brown Little clay and iron oxides Contains high levels of organic matter B Red brown and yellow Contain little organic matter Rich in clay, calcium carbonate and irons E Light gray to white No clay, iron and organic material C Differs Parent rock Geologists and soil scientists have studied soil profiles and noted that they all fit into 12 soil orders. Some if these soil orders are founds in mountainous areas, tropical climatic and polar climatic regions. Among the twelve soil orders, Indiana is primarily covered by three soil orders. These include Mollisols, Alfisols and Entisols. These soil orders are still divided into smaller sub groupings of soil types (Indiana University 5). Works Cited Brady, N. C., and R. R. Weil. The nature and properties of soils: Texte imprimé. Upper Saddle River, N.J: Pearson Prentice Hall, 2008. Print. Bryant-Mole, K., and B. Watts. Soil. Austin, Tex: Raintree Steck-Vaughn, 1996. Print. Burton, T. "Indiana Soils:Evaluation and Conservation Online Manual." Purdue Agronomy. N.p., 2004. Web.  2013. . Indiana University. "G135 - Indiana Geology." IUPUI : Indiana University-Purdue University Indianapolis. N.p., 2007. Web.  2013. . Millar, C. E., and L. M. Turk. Fundamentals of Soil Science. Delhi: Biotech Books, 2001. Print. Read More